diff --git a/conftest.py b/conftest.py
index 5307d7f6233..a42ac87c67d 100644
--- a/conftest.py
+++ b/conftest.py
@@ -32,7 +32,6 @@
 )
 from sage.doctest.parsing import SageDocTestParser, SageOutputChecker
 
-
 class SageDoctestModule(DoctestModule):
     """
     This is essentially a copy of `DoctestModule` from
@@ -125,15 +124,26 @@ def _find(
             checker=SageOutputChecker(),
             continue_on_failure=_get_continue_on_failure(self.config),
         )
+        # Monkey patch exception reporting to ignore FeatureNotPresentError
+        old_report_unexpected_exception = runner.report_unexpected_exception
+        def _report_unexpected_exception(self, test, example, exc_info):
+            if isinstance(exc_info[1], FeatureNotPresentError):
+                # Ignore FeatureNotPresentError
+                # (it's not an error in the doctest)
+                return
+            return old_report_unexpected_exception(self, test, example, exc_info)
+        runner.report_unexpected_exception = _report_unexpected_exception
         try:
+            print(f"Collecting doctests from { self.path }: { module }")
             for test in finder.find(module, module.__name__):
+                print(test)
                 if test.examples:  # skip empty doctests
                     yield DoctestItem.from_parent(
                         self, name=test.name, runner=runner, dtest=test
                     )
         except FeatureNotPresentError as exception:
             pytest.skip(
-                f"unable to import module { self.path } due to missing feature { exception.feature.name }"
+                f"unable to import module { self.path } due to { exception }"
             )
         except ModuleNotFoundError as exception:
             # TODO: Remove this once all optional things are using Features
@@ -175,6 +185,7 @@ def pytest_collect_file(
         # We don't allow pytests to be defined in Cython files.
         # Normally, Cython files are filtered out already by pytest and we only
         # hit this here if someone explicitly runs `pytest some_file.pyx`.
+        #return SageDoctestModule.from_parent(parent, path=file_path)
         return IgnoreCollector.from_parent(parent)
     elif file_path.suffix == ".py":
         if parent.config.option.doctest:
diff --git a/src/sage/algebras/fusion_rings/meson.build b/src/sage/algebras/fusion_rings/meson.build
index 221cce6146e..692e046cf71 100644
--- a/src/sage/algebras/fusion_rings/meson.build
+++ b/src/sage/algebras/fusion_rings/meson.build
@@ -35,6 +35,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gmp, singular]
   py.extension_module(
     name,
     sources: pyx,
@@ -42,7 +43,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ntl, inc_numpy, inc_rings],
-    dependencies: [py_dep, cysignals, gmp, singular],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'algebras/fusion_rings',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/algebras/letterplace/meson.build b/src/sage/algebras/letterplace/meson.build
index 3e429eb420a..8f3cef0ffbc 100644
--- a/src/sage/algebras/letterplace/meson.build
+++ b/src/sage/algebras/letterplace/meson.build
@@ -15,6 +15,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, gmp, singular]
   py.extension_module(
     name,
     sources: pyx,
@@ -22,7 +23,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, gmp, singular],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'algebras/letterplace',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/algebras/quatalg/meson.build b/src/sage/algebras/quatalg/meson.build
index 25c4adfc46c..37627e67218 100644
--- a/src/sage/algebras/quatalg/meson.build
+++ b/src/sage/algebras/quatalg/meson.build
@@ -12,6 +12,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, flint, gmp, m, ntl]
   py.extension_module(
     name,
     sources: pyx,
@@ -19,7 +20,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_ntl, inc_rings],
-    dependencies: [py_dep, flint, gmp, m, ntl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'algebras/quatalg',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/calculus/meson.build b/src/sage/calculus/meson.build
index 3bedeb2220a..36f021ec132 100644
--- a/src/sage/calculus/meson.build
+++ b/src/sage/calculus/meson.build
@@ -25,14 +25,33 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gsl, interpreters_dep]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/calculus',
     install: true,
     include_directories: [inc_numpy],
-    dependencies: [py_dep, cysignals, gmp, gsl, interpreters_dep],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'calculus',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 subdir('transforms')
diff --git a/src/sage/calculus/transforms/meson.build b/src/sage/calculus/transforms/meson.build
index 11ffa9f8ec1..3a6147bc0c4 100644
--- a/src/sage/calculus/transforms/meson.build
+++ b/src/sage/calculus/transforms/meson.build
@@ -10,13 +10,32 @@ py.install_sources(
 extension_data = {'dwt' : files('dwt.pyx'), 'fft' : files('fft.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gsl]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/calculus/transforms',
     install: true,
     include_directories: [inc_gsl],
-    dependencies: [py_dep, cysignals, gmp, gsl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'calculus/transforms',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/coding/codecan/meson.build b/src/sage/coding/codecan/meson.build
index 1ccaca09b2a..c67b2710a4c 100644
--- a/src/sage/coding/codecan/meson.build
+++ b/src/sage/coding/codecan/meson.build
@@ -11,6 +11,7 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gap, gmp]
   py.extension_module(
     name,
     sources: pyx,
@@ -22,7 +23,25 @@ foreach name, pyx : extension_data
       inc_partn_ref2,
       inc_rings,
     ],
-    dependencies: [py_dep, cysignals, gap, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'coding/codecan',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/combinat/meson.build b/src/sage/combinat/meson.build
index 441caadca17..3a652716463 100644
--- a/src/sage/combinat/meson.build
+++ b/src/sage/combinat/meson.build
@@ -159,6 +159,24 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_data_structures, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'combinat',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('chas', install_dir: sage_install_dir / 'combinat')
diff --git a/src/sage/combinat/posets/meson.build b/src/sage/combinat/posets/meson.build
index 9832967b4ff..29d705208df 100644
--- a/src/sage/combinat/posets/meson.build
+++ b/src/sage/combinat/posets/meson.build
@@ -23,13 +23,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/combinat/posets',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_rings],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'combinat/posets',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/combinat/root_system/meson.build b/src/sage/combinat/root_system/meson.build
index 629c67bcdd6..e85d343c0e8 100644
--- a/src/sage/combinat/root_system/meson.build
+++ b/src/sage/combinat/root_system/meson.build
@@ -78,5 +78,23 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'combinat/root_system',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/data_structures/meson.build b/src/sage/data_structures/meson.build
index 8c100328378..58eba2a47c5 100644
--- a/src/sage/data_structures/meson.build
+++ b/src/sage/data_structures/meson.build
@@ -27,6 +27,7 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
@@ -38,13 +39,28 @@ foreach name, pyx : extension_data
       inc_flint,
       inc_rings,
     ],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'data_structures',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
-extension_data_cpp = {
-  'pairing_heap' : files('pairing_heap.pyx'),
-}
+extension_data_cpp = {'pairing_heap' : files('pairing_heap.pyx')}
 
 foreach name, pyx : extension_data_cpp
   py.extension_module(
diff --git a/src/sage/features/__init__.py b/src/sage/features/__init__.py
index ac4a0bcd97f..e7ed24dd619 100644
--- a/src/sage/features/__init__.py
+++ b/src/sage/features/__init__.py
@@ -435,7 +435,7 @@ class FeatureNotPresentError(RuntimeError):
         ...
         FeatureNotPresentError: missing is not available.
     """
-    def __init__(self, feature, reason=None, resolution=None):
+    def __init__(self, feature: Feature | None = None, reason: str | None=None, resolution: str | None =None):
         self.feature = feature
         self.reason = reason
         self._resolution = resolution
@@ -459,12 +459,13 @@ def __str__(self):
             FeatureNotPresentError: gap_package_gapZuHoh8Uu is not available.
             `LoadPackage("gapZuHoh8Uu")` evaluated to `fail` in GAP.
         """
-        lines = ["{feature} is not available.".format(feature=self.feature.name)]
+        lines = []
+        if self.feature:
+            lines.append(f"{self.feature.name} is not available.")
         if self.reason:
             lines.append(self.reason)
-        resolution = self.resolution
-        if resolution:
-            lines.append(str(resolution))
+        if self._resolution:
+            lines.append(str(self._resolution))
         return "\n".join(lines)
 
 
@@ -963,8 +964,8 @@ def __init__(self, name, **kwds):
 
     def _is_present(self):
         r"""
-        Return whether the module can be imported. This is determined by
-        actually importing it.
+        Return whether the module can be found. It is not tested whether the
+        module can be imported or otherwise is functional.
 
         EXAMPLES::
 
@@ -974,9 +975,9 @@ def _is_present(self):
             sage: PythonModule("_no_such_module_").is_present()
             FeatureTestResult('_no_such_module_', False)
         """
-        import importlib
+        import importlib.util
         try:
-            importlib.import_module(self.name)
+            importlib.util.find_spec(self.name)
         except ImportError as exception:
-            return FeatureTestResult(self, False, reason=f"Failed to import `{self.name}`: {exception}")
+            return FeatureTestResult(self, False, reason=f"Failed to find `{self.name}`: {exception}")
         return FeatureTestResult(self, True, reason=f"Successfully imported `{self.name}`.")
diff --git a/src/sage/features/mock.py b/src/sage/features/mock.py
new file mode 100644
index 00000000000..dcd682c37bd
--- /dev/null
+++ b/src/sage/features/mock.py
@@ -0,0 +1,220 @@
+from collections.abc import Iterable
+from typing import Any
+
+from sage.features import FeatureNotPresentError
+
+class MockConstructor(type):
+    _name: str
+
+    def __new__(cls, name: str, bases: tuple[type, ...], attrs: dict[str, Any], module: str | None = None):
+        print(f"Constructor: __new__")
+        attrs["_name"] = name
+        attrs["_module"] = module
+        return super().__new__(cls, name, bases, attrs)
+
+        # if len(args) == 3 and isinstance(args[1], tuple):
+        #     super().__new__(cls, *args)
+        # return cls
+    
+    # def __init__(self, *args, name: str, **kwargs):
+    #     self._name = name
+
+    # def __getattr__(self, attr: str) -> Any:
+    #     # For debugging:
+    #     print(f"__getattr__ {attr}")
+    #     return mock(f"{self._name}.{attr}")
+
+class MockInstance:#(metaclass=Mock):
+    _name: str
+    _module: str
+    #__pyx_vtable__ = 1
+
+    def __getattr__(self, attr: str) -> Any:
+        # For debugging:
+        print(f"__getattr__ instance {attr}")
+        if attr in ("_name", "_module"):
+            raise NotImplementedError(attr)
+        # if attr == '__pyx_vtable__':
+        #     return 1
+
+        return mock(self._module, f"{self._name}.{attr}")
+
+# class Wrapper(type):
+#     _key: str
+
+#     def __new__(cls, *args, **kwargs):
+#         # For debugging:
+#         print(f"__new__ {len(args)}")
+#     #    return super().__new__(cls)
+#         if len(args) == 3 and isinstance(args[1], tuple):
+#             super().__new__(cls, *args)
+#             #superclass = args[1][-1].__class__
+#             #print(f"__new__ {args[0], superclass.__display_name__}")
+#             #if superclass is cls:
+#             #    return super().__new__(
+#             #        args[0],
+#             #        superclass.__display_name__,
+#             #        superclass=superclass,
+#             #        attributes=args[2])
+#         #cls._key = args[0]
+#         return cls
+#         #raise FeatureNotPresentError(
+#         #    reason=f"A dependency of the package {__name__} is not available, trying to access {args[0]}"
+#         #)
+
+#     def __init__(self, *args, **kwargs):
+#         print(f"__init__")
+#         #self._key = name
+
+#     def raise_error(self):
+#         raise FeatureNotPresentError(
+#             reason=f"A dependency of the package {__name__} is not available, trying to access {self._key}"
+#         )
+
+#     def __basicsize__(self):
+#         print(f"__basicsize__")
+#         self.raise_error()
+
+    def __call__(self, *args, **kwargs):
+        # For debugging:
+        print(f"__call__{self._name}")
+        #for arg in args:
+        #   for subarg in arg:
+        #       print(type(subarg))
+        self.raise_error()
+
+    # def __mro_entries__(self, bases):
+    #     """
+    #     In case someone tries to inherit from this class, we substitute the bases with 
+    #     a Wrapper.
+    #     See https://docs.python.org/3/reference/datamodel.html#object.__mro_entries__
+    #     """
+    #     return (self.__class__, )
+
+#     def __getattribute__(self, attr: str) -> Any:
+#         if attr in ('_key', 'raise_error'):
+#             return super().__getattribute__(attr)
+#         # For debugging:
+#         print(f"__getattr__ {attr}")
+#         return self
+
+    def __repr__(self):
+        print(f"__repr__")
+        return f"<Mock name='{self._name}' module='{self._module}'>"
+        #return super().__repr__()
+        #self.raise_error()
+
+#     def __eq__(self, value: object) -> bool:
+#         print(f"__eq__ {value}")
+#         return super().__eq__(value)
+    
+#     def __subclasscheck__(self, subclass: type) -> bool:
+#         print(f"__subclasscheck__ {subclass}")
+#         return True
+    
+#     def __instancecheck__(self, instance: object) -> bool:
+#         print(f"__instancecheck__ {instance}")
+#         return True
+
+#     @classmethod
+#     def __subclasshook__(cls, subclass: type) -> bool:
+#         print(f"__subclasshook__ {subclass}")
+#         return True
+
+#     def __init_subclass__(cls, **kwargs):
+#         print(f"__init_subclass__ {kwargs}")
+#         return super().__init_subclass__(**kwargs)
+
+
+# class Mock:#(metaclass=Wrapper):
+#     _key: str
+
+#     def __init__(self, *args, **kwargs):
+#         print(f"__init__")
+#         self._key = args[0]
+
+    def raise_error(self):
+        raise FeatureNotPresentError(
+            reason=f"A dependency of the package '{self._module}' is not available, trying to access '{self._name}'"
+        )
+
+#     def __basicsize__(self):
+#         print(f"__basicsize__")
+#         self.raise_error()
+
+#     def __call__(self, *args, **kwargs):
+#         # For debugging:
+#         print(f"__call__{self._key}")
+#         for arg in args:
+#            for subarg in arg:
+#                print(type(subarg))
+#         self.raise_error()
+
+    def __mro_entries__(self, bases):
+        """
+        In case someone tries to inherit from this class, we substitute the bases with 
+        a Wrapper.
+        See https://docs.python.org/3/reference/datamodel.html#object.__mro_entries__
+        """
+        print(f"__mro_entries__ {bases}")
+        #MockCls = MockConstructor(self._name, (MockInstance, ), {}, module=self._module)
+        #return (MockCls, )
+        MockCls = self.__class__
+        MockCls._module = self._module
+        MockCls._name = self._name
+        return (MockCls, )
+
+#     def __getattribute__(self, attr: str) -> Any:
+#         if attr in ('_key', 'raise_error'):
+#             return super().__getattribute__(attr)
+#         # For debugging:
+#         print(f"__getattr__ {attr}")
+#         return self
+
+#     def __repr__(self):
+#         print(f"__repr__")
+#         return self._key
+#         #return super().__repr__()
+#         #self.raise_error()
+
+#     def __eq__(self, value: object) -> bool:
+#         print(f"__eq__ {value}")
+#         return super().__eq__(value)
+    
+#     def __subclasscheck__(self, subclass: type) -> bool:
+#         print(f"__subclasscheck__ {subclass}")
+#         return True
+    
+#     def __instancecheck__(self, instance: object) -> bool:
+#         print(f"__instancecheck__ {instance}")
+#         return True
+
+#     @classmethod
+#     def __subclasshook__(cls, subclass: type) -> bool:
+#         print(f"__subclasshook__ {subclass}")
+#         return True
+
+#     def __init_subclass__(cls, **kwargs):
+#         print(f"__init_subclass__ {kwargs}")
+#         return super().__init_subclass__(**kwargs)
+
+
+def mock(module: str, name: str) -> MockInstance:
+    r"""
+    Return a mock object.
+
+    EXAMPLES::
+
+        sage: from sage.features.mock import mock
+        sage: mock('foo')
+        <Mock name='foo'>
+    """
+    print(f"mock {module}.{name}")
+    mock = MockInstance()
+    mock._module = module
+    mock._name = name
+    return mock
+    #MockCls = MockConstructor(name, (MockInstance, ), {}, module=module)
+    #return MockCls()
+    #return #MockInstance(module, name)
+    #return Mock.__new__(MockInstance, (), {})
diff --git a/src/sage/features/mock_test.py b/src/sage/features/mock_test.py
new file mode 100644
index 00000000000..40f99ec7903
--- /dev/null
+++ b/src/sage/features/mock_test.py
@@ -0,0 +1,68 @@
+import pytest
+
+from sage.features import FeatureNotPresentError
+from sage.features.mock import MockInstance, mock
+
+
+def test_mock_creation():
+    m = mock('module', 'foo')
+    assert isinstance(m, MockInstance)
+    assert m._name == 'foo'
+    assert m._module == 'module'
+
+def test_mock_repr_returns_name():
+    m = mock('module', 'foo')
+    assert repr(m) == "<Mock name='foo' module='module'>"
+
+def test_mock_call_raises_exception():
+    m = mock('module', 'foo')
+    with pytest.raises(FeatureNotPresentError):
+        m()
+
+def test_mock_call_function_raises_exception():
+    m = mock('module', 'foo')
+    with pytest.raises(FeatureNotPresentError):
+        m.function() # type: ignore
+
+def test_mock_get_attribute_returns_another_mock():
+    m = mock('module', 'foo')
+    attribute = m.bar # type: ignore
+    assert isinstance(attribute, MockInstance)
+    assert attribute._name == 'foo.bar'
+    assert attribute._module == 'module'
+
+def test_can_inherit_from_mock_without_raising_exception():
+    m = mock('module', 'foo')
+    class MyMock(m): # type: ignore
+        pass
+    with pytest.raises(FeatureNotPresentError):
+        MyMock().bar()
+
+def test_can_inherit_from_mock_with_other_bases():
+    m = mock('module', 'foo')
+    class Bar:
+        pass
+    class MyMock(m, Bar): # type: ignore
+        pass
+    with pytest.raises(FeatureNotPresentError):
+        MyMock().bar()
+
+def test_can_inherit_from_mock_with_other_metaclass():
+    m = mock('module', 'foo')
+    class MyMeta(type):
+        def __new__(cls, name, bases, dct):
+            return super().__new__(cls, name, bases, dct)
+    class Bar(metaclass=MyMeta):
+        pass
+    class MyMock(m, Bar): # type: ignore
+        pass
+    with pytest.raises(FeatureNotPresentError):
+        MyMock().bar()
+
+# def test_can_inherit_from_mock_and_algebra_element():
+#     m = mock('module', 'foo')
+#     from sage.structure.element import AlgebraElement
+#     class MyMock(m, AlgebraElement):
+#         pass
+#     with pytest.raises(FeatureNotPresentError):
+#         MyMock()
diff --git a/src/sage/features/not_available.py.in b/src/sage/features/not_available.py.in
new file mode 100644
index 00000000000..37313a6dcab
--- /dev/null
+++ b/src/sage/features/not_available.py.in
@@ -0,0 +1,14 @@
+# This file will be installed whenever the corresponding Cython extension module
+# cannot be built due to missing dependencies. It provides a mock object that allows to import
+# arbitrary attributes without raising an ImportError. However, when actually invoking
+# any function on the mock a FeatureNotPresentError is raised.
+
+from sage.features.mock import mock
+
+def __getattr__(key: str):
+    if key == '__path__':
+        # This is a special attribute that Python looks for when importing a package.
+        # We raise AttributeError to prevent Python from querying every attribute twice.
+        # https://stackoverflow.com/questions/56786604/import-modules-that-dont-exist-yet
+        raise AttributeError
+    return mock(__name__, key)
diff --git a/src/sage/geometry/meson.build b/src/sage/geometry/meson.build
index 3b48404564d..7bb9ae89a8b 100644
--- a/src/sage/geometry/meson.build
+++ b/src/sage/geometry/meson.build
@@ -46,6 +46,24 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'geometry',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('hyperbolic_space', install_dir: sage_install_dir / 'geometry')
diff --git a/src/sage/graphs/graph_decompositions/meson.build b/src/sage/graphs/graph_decompositions/meson.build
index 913c682ebac..3324c751476 100644
--- a/src/sage/graphs/graph_decompositions/meson.build
+++ b/src/sage/graphs/graph_decompositions/meson.build
@@ -31,14 +31,33 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, rw]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/graphs/graph_decompositions',
     install: true,
     include_directories: [inc_cpython, inc_data_structures],
-    dependencies: [py_dep, cysignals, gmp, rw],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'graphs/graph_decompositions',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -48,6 +67,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gmp, rw]
   py.extension_module(
     name,
     sources: pyx,
@@ -55,10 +75,29 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_data_structures],
-    dependencies: [py_dep, cysignals, gmp, rw],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'graphs/graph_decompositions',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
+deps = [py_dep, cysignals, tdlib]
 py.extension_module(
   'tdlib',
   sources: 'tdlib.pyx',
@@ -66,6 +105,22 @@ py.extension_module(
   install: true,
   override_options: ['cython_language=cpp'],
   include_directories: [inc_cpython, inc_data_structures],
-  dependencies: [py_dep, cysignals, tdlib],
+  dependencies: deps,
 )
-
+all_deps_found = true
+foreach dep : deps
+  if not dep.found()
+    all_deps_found = false
+    break
+  endif
+endforeach
+if not all_deps_found
+  configure_file(
+    input: not_available,
+    output: name + '.py',
+    install_tag: 'python-runtime',
+    install_dir: sage_install_dir / 'graphs/graph_decompositions',
+    install: true,
+    copy: true,
+  )
+endif
diff --git a/src/sage/graphs/meson.build b/src/sage/graphs/meson.build
index 842501734e5..82528608e6c 100644
--- a/src/sage/graphs/meson.build
+++ b/src/sage/graphs/meson.build
@@ -81,6 +81,7 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, cliquer, flint, gmp, planarity]
   py.extension_module(
     name,
     sources: pyx,
@@ -92,8 +93,26 @@ foreach name, pyx : extension_data
       inc_flint,
       inc_rings,
     ],
-    dependencies: [py_dep, cysignals, cliquer, flint, gmp, planarity],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'graphs',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -104,6 +123,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, flint, gmp, planarity]
   py.extension_module(
     name,
     sources: pyx,
@@ -116,10 +136,29 @@ foreach name, pyx : extension_data_cpp
       inc_flint,
       inc_rings,
     ],
-    dependencies: [py_dep, cysignals, flint, gmp, planarity],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'graphs',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
+deps = [py_dep, cysignals, bliss]
 py.extension_module(
   'bliss',
   sources: files('bliss.pyx'),
@@ -127,9 +166,27 @@ py.extension_module(
   install: true,
   override_options: ['cython_language=cpp'],
   include_directories: [inc_cpython, inc_data_structures, inc_flint, inc_rings],
-  dependencies: [py_dep, cysignals, bliss],
+  dependencies: deps,
 )
+all_deps_found = true
+foreach dep : deps
+  if not dep.found()
+    all_deps_found = false
+    break
+  endif
+endforeach
+if not all_deps_found
+  configure_file(
+    input: not_available,
+    output: 'bliss.py',
+    install_tag: 'python-runtime',
+    install_dir: sage_install_dir / 'graphs',
+    install: true,
+    copy: true,
+  )
+endif
 
+deps = [py_dep, cysignals, mcqd]
 py.extension_module(
   'mcqd',
   sources: files('mcqd.pyx'),
@@ -137,8 +194,25 @@ py.extension_module(
   install: true,
   override_options: ['cython_language=cpp'],
   include_directories: [inc_cpython, inc_data_structures, inc_flint, inc_rings],
-  dependencies: [py_dep, cysignals, mcqd],
+  dependencies: deps,
 )
+all_deps_found = true
+foreach dep : deps
+  if not dep.found()
+    all_deps_found = false
+    break
+  endif
+endforeach
+if not all_deps_found
+  configure_file(
+    input: not_available,
+    output: 'mcqd.py',
+    install_tag: 'python-runtime',
+    install_dir: sage_install_dir / 'graphs',
+    install: true,
+    copy: true,
+  )
+endif
 
 subdir('base')
 subdir('generators')
diff --git a/src/sage/groups/matrix_gps/meson.build b/src/sage/groups/matrix_gps/meson.build
index 77c70adf7fa..6c5734bb0d6 100644
--- a/src/sage/groups/matrix_gps/meson.build
+++ b/src/sage/groups/matrix_gps/meson.build
@@ -47,5 +47,23 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'groups/matrix_gps',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/groups/meson.build b/src/sage/groups/meson.build
index 37ba1028d5e..a80c70bd605 100644
--- a/src/sage/groups/meson.build
+++ b/src/sage/groups/meson.build
@@ -50,6 +50,24 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'groups',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('abelian_gps', install_dir: sage_install_dir / 'groups')
diff --git a/src/sage/groups/perm_gps/meson.build b/src/sage/groups/perm_gps/meson.build
index 6ad30d99fe2..8dedf696286 100644
--- a/src/sage/groups/perm_gps/meson.build
+++ b/src/sage/groups/perm_gps/meson.build
@@ -15,14 +15,33 @@ py.install_sources(
 extension_data = {'permgroup_element' : files('permgroup_element.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gap, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/groups/perm_gps',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_rings],
-    dependencies: [py_dep, cysignals, gap, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'groups/perm_gps',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 subdir('partn_ref')
diff --git a/src/sage/groups/perm_gps/partn_ref2/meson.build b/src/sage/groups/perm_gps/partn_ref2/meson.build
index 69b9bee042d..5578bf3fc09 100644
--- a/src/sage/groups/perm_gps/partn_ref2/meson.build
+++ b/src/sage/groups/perm_gps/partn_ref2/meson.build
@@ -8,13 +8,32 @@ py.install_sources(
 extension_data = {'refinement_generic' : files('refinement_generic.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gap]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/groups/perm_gps/partn_ref2',
     install: true,
     include_directories: [inc_cpython, inc_data_structures, inc_partn_ref2],
-    dependencies: [py_dep, cysignals, gmp, gap],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'groups/perm_gps/partn_ref2',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/interfaces/singular.py b/src/sage/interfaces/singular.py
index 59d01f4493d..bf9b3b76856 100644
--- a/src/sage/interfaces/singular.py
+++ b/src/sage/interfaces/singular.py
@@ -342,6 +342,8 @@
 import shlex
 import time
 
+from sage.features import FeatureNotPresentError
+
 from .expect import Expect, ExpectElement, FunctionElement, ExpectFunction
 
 import sage.interfaces.abc
@@ -2450,7 +2452,10 @@ def get_docstring(name, prefix=False, code=False):
     return result
 
 
-singular = Singular()
+try:
+    singular = Singular()
+except FeatureNotPresentError:
+    singular = None
 
 
 def reduce_load_Singular():
diff --git a/src/sage/lfunctions/meson.build b/src/sage/lfunctions/meson.build
index 24e2f156f5e..3c89af63989 100644
--- a/src/sage/lfunctions/meson.build
+++ b/src/sage/lfunctions/meson.build
@@ -11,13 +11,32 @@ py.install_sources(
 extension_data = {'zero_sums' : files('zero_sums.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/lfunctions',
     install: true,
     include_directories: [inc_flint],
-    dependencies: [py_dep, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'lfunctions',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/arb/meson.build b/src/sage/libs/arb/meson.build
index aa98fb8ff3a..5714eec75e4 100644
--- a/src/sage/libs/arb/meson.build
+++ b/src/sage/libs/arb/meson.build
@@ -21,13 +21,32 @@ py.install_sources(
 extension_data = {'arith' : files('arith.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, flint, gmp, mpfr]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/arb',
     install: true,
     include_directories: [inc_cpython, inc_flint, inc_rings],
-    dependencies: [py_dep, flint, gmp, mpfr],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/arb',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/coxeter3/meson.build b/src/sage/libs/coxeter3/meson.build
index ee51998f27d..8ae975f159c 100644
--- a/src/sage/libs/coxeter3/meson.build
+++ b/src/sage/libs/coxeter3/meson.build
@@ -11,6 +11,7 @@ py.install_sources(
 extension_data_cpp = {'coxeter': files('coxeter.pyx')}
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, coxeter3]
   py.extension_module(
     name,
     sources: pyx,
@@ -18,6 +19,24 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython],
-    dependencies: [py_dep, cysignals, coxeter3],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/coxeter3',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
diff --git a/src/sage/libs/eclib/meson.build b/src/sage/libs/eclib/meson.build
index dd6ecc3f581..7db45ac9018 100644
--- a/src/sage/libs/eclib/meson.build
+++ b/src/sage/libs/eclib/meson.build
@@ -18,6 +18,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, ec, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
@@ -25,7 +26,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_ntl, inc_rings],
-    dependencies: [py_dep, cysignals, ec, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/eclib',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/flint/meson.build b/src/sage/libs/flint/meson.build
index fe12b28b5f7..dcc74ce2b36 100644
--- a/src/sage/libs/flint/meson.build
+++ b/src/sage/libs/flint/meson.build
@@ -165,13 +165,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp, mpfr]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/flint',
     install: true,
     include_directories: [inc_cpython, inc_flint, inc_rings],
-    dependencies: [py_dep, cysignals, flint, gmp, mpfr],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/flint',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/gap/meson.build b/src/sage/libs/gap/meson.build
index def07898f4c..b92336fd09c 100644
--- a/src/sage/libs/gap/meson.build
+++ b/src/sage/libs/gap/meson.build
@@ -27,13 +27,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gap, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/gap',
     install: true,
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, cysignals, gap, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/gap',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/giac/meson.build b/src/sage/libs/giac/meson.build
index 6dda5a6c8a7..f519c968cc1 100644
--- a/src/sage/libs/giac/meson.build
+++ b/src/sage/libs/giac/meson.build
@@ -5,6 +5,7 @@ py.install_sources('__init__.py', 'giac.pxd', 'misc.h', subdir: 'sage/libs/giac'
 extension_data_cpp = {'giac': files('giac.pyx')}
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, giac, gmp]
   py.extension_module(
     name,
     sources: pyx,
@@ -12,6 +13,24 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_rings],
-    dependencies: [py_dep, cysignals, giac, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/giac',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
diff --git a/src/sage/libs/gsl/meson.build b/src/sage/libs/gsl/meson.build
index ea5eac5e93a..75fa59cfc61 100644
--- a/src/sage/libs/gsl/meson.build
+++ b/src/sage/libs/gsl/meson.build
@@ -70,13 +70,32 @@ py.install_sources(
 extension_data = {'array' : files('array.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gsl]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/gsl',
     install: true,
     include_directories: [inc_gsl],
-    dependencies: [py_dep, cysignals, gmp, gsl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/gsl',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/lcalc/meson.build b/src/sage/libs/lcalc/meson.build
index aa6d9296948..a6ad2db95e1 100644
--- a/src/sage/libs/lcalc/meson.build
+++ b/src/sage/libs/lcalc/meson.build
@@ -10,6 +10,7 @@ py.install_sources(
 extension_data_cpp = {'lcalc_Lfunction': files('lcalc_Lfunction.pyx')}
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cypari2, cysignals, gmp, lcalc, m, mpfr, ntl]
   py.extension_module(
     name,
     sources: pyx,
@@ -17,7 +18,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, cypari2, cysignals, gmp, lcalc, m, mpfr, ntl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/lcalc',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/linbox/meson.build b/src/sage/libs/linbox/meson.build
index 252a6ae0f9e..45569638d99 100644
--- a/src/sage/libs/linbox/meson.build
+++ b/src/sage/libs/linbox/meson.build
@@ -13,6 +13,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, blas, flint, fplll, givaro, gmp, gmpxx, linbox]
   py.extension_module(
     name,
     sources: pyx,
@@ -20,7 +21,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_flint],
-    dependencies: [py_dep, blas, flint, fplll, givaro, gmp, gmpxx, linbox],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/linbox',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/meson.build b/src/sage/libs/meson.build
index 53470399d46..eb5f9e527b6 100644
--- a/src/sage/libs/meson.build
+++ b/src/sage/libs/meson.build
@@ -52,11 +52,30 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {'braiding': files('braiding.pyx')}
 
 foreach name, pyx : extension_data_cpp
+  deps = dependencies
   py.extension_module(
     name,
     sources: pyx,
@@ -66,6 +85,24 @@ foreach name, pyx : extension_data_cpp
     include_directories: [inc_cpython, inc_rings],
     dependencies: dependencies,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 subdir('arb')
diff --git a/src/sage/libs/mpmath/meson.build b/src/sage/libs/mpmath/meson.build
index a197516f9f1..ba295ed00cd 100644
--- a/src/sage/libs/mpmath/meson.build
+++ b/src/sage/libs/mpmath/meson.build
@@ -15,13 +15,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, mpfr]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/mpmath',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_rings],
-    dependencies: [py_dep, cysignals, gmp, mpfr],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/mpmath',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/ntl/__init__.py b/src/sage/libs/ntl/__init__.py
index 0ab0a2c43e7..0dfd674687a 100644
--- a/src/sage/libs/ntl/__init__.py
+++ b/src/sage/libs/ntl/__init__.py
@@ -1,3 +1,7 @@
+from sage.features import FeatureNotPresentError
 from sage.libs.ntl.error import setup_NTL_error_callback
 
-setup_NTL_error_callback()
+try:
+    setup_NTL_error_callback()
+except FeatureNotPresentError:
+    pass
diff --git a/src/sage/libs/ntl/meson.build b/src/sage/libs/ntl/meson.build
index 7f78db280fe..14f05f9e00e 100644
--- a/src/sage/libs/ntl/meson.build
+++ b/src/sage/libs/ntl/meson.build
@@ -71,6 +71,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gmp, m, ntl]
   py.extension_module(
     name,
     sources: pyx,
@@ -84,7 +85,25 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [py_dep, cysignals, gmp, m, ntl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/ntl',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/pari/meson.build b/src/sage/libs/pari/meson.build
index 5952060267c..1ad7d210553 100644
--- a/src/sage/libs/pari/meson.build
+++ b/src/sage/libs/pari/meson.build
@@ -24,13 +24,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cypari2, cysignals, flint, gmp, gsl, mpfr, pari]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/pari',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_gsl, inc_rings],
-    dependencies: [py_dep, cypari2, cysignals, flint, gmp, gsl, mpfr, pari],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/pari',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/singular/meson.build b/src/sage/libs/singular/meson.build
index 52ece586caa..264fd9f5470 100644
--- a/src/sage/libs/singular/meson.build
+++ b/src/sage/libs/singular/meson.build
@@ -21,6 +21,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, givaro, gmp, singular]
   py.extension_module(
     name,
     sources: pyx,
@@ -28,7 +29,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ntl, inc_rings, inc_rings_finite],
-    dependencies: [py_dep, cysignals, givaro, gmp, singular],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/singular',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/libs/symmetrica/all.py b/src/sage/libs/symmetrica/all.py
index f69490654af..bc36f1d841c 100644
--- a/src/sage/libs/symmetrica/all.py
+++ b/src/sage/libs/symmetrica/all.py
@@ -1,4 +1,5 @@
 # from symmetrica import *
+from sage.features import FeatureNotPresentError
 
 from sage.libs.symmetrica.symmetrica import start
 
@@ -97,4 +98,8 @@
 from sage.libs.symmetrica.symmetrica import scalarproduct_schubert_symmetrica as scalarproduct_schubert
 from sage.libs.symmetrica.symmetrica import divdiff_schubert_symmetrica as divdiff_schubert
 
-start()
+try:
+    start()
+except FeatureNotPresentError:
+    # Symmetrica is not available, so we do nothing
+    pass
diff --git a/src/sage/libs/symmetrica/meson.build b/src/sage/libs/symmetrica/meson.build
index 9294ebe3b03..d7eed7eef6e 100644
--- a/src/sage/libs/symmetrica/meson.build
+++ b/src/sage/libs/symmetrica/meson.build
@@ -6,13 +6,31 @@ py.install_sources('__init__.py', 'all.py', subdir: 'sage/libs/symmetrica')
 extension_data = {'symmetrica' : files('symmetrica.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, symmetrica]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/libs/symmetrica',
     install: true,
     include_directories: [],
-    dependencies: [py_dep, cysignals, gmp, symmetrica],
+    dependencies: deps,
   )
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'libs/symmetrica',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/matrix/meson.build b/src/sage/matrix/meson.build
index 0e51c764de7..b80c0f58143 100644
--- a/src/sage/matrix/meson.build
+++ b/src/sage/matrix/meson.build
@@ -126,6 +126,24 @@ foreach name, pyx : extension_data
     ],
     dependencies: dependencies,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'matrix',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -142,6 +160,30 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [
+    py_dep,
+    blas,
+    cypari2,
+    cysignals,
+    fflas,
+    flint,
+    gd,
+    givaro,
+    gmp,
+    gmpxx,
+    iml,
+    linbox,
+    m,
+    m4ri,
+    m4rie,
+    mpfi,
+    mpfr,
+    ntl,
+    pari,
+    png,
+    singular,
+    zlib,
+  ]
   py.extension_module(
     name,
     sources: pyx,
@@ -157,30 +199,25 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [
-      py_dep,
-      blas,
-      cypari2,
-      cysignals,
-      fflas,
-      flint,
-      gd,
-      givaro,
-      gmp,
-      gmpxx,
-      iml,
-      linbox,
-      m,
-      m4ri,
-      m4rie,
-      mpfi,
-      mpfr,
-      ntl,
-      pari,
-      png,
-      singular,
-      zlib,
-    ],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'matrix',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/meson.build b/src/sage/meson.build
index d0cf55161b9..2f83dc2e27e 100644
--- a/src/sage/meson.build
+++ b/src/sage/meson.build
@@ -63,6 +63,8 @@ config_file = configure_file(
   configuration: conf_data,
 )
 
+not_available = files('features/not_available.py.in')
+
 # Packages that need no processing and can be installed directly
 no_processing = [
   'databases',
diff --git a/src/sage/misc/meson.build b/src/sage/misc/meson.build
index 97d4bf9e6a1..7aa87d54f2a 100644
--- a/src/sage/misc/meson.build
+++ b/src/sage/misc/meson.build
@@ -138,5 +138,23 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'misc',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/modular/arithgroup/meson.build b/src/sage/modular/arithgroup/meson.build
index 52475097b34..d088d1b45f2 100644
--- a/src/sage/modular/arithgroup/meson.build
+++ b/src/sage/modular/arithgroup/meson.build
@@ -19,14 +19,33 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/modular/arithgroup',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_rings],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modular/arithgroup',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 # Manually create header file, which otherwise is not found
@@ -53,6 +72,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, flint, gmp, gmpxx]
   py.extension_module(
     name,
     sources: pyx,
@@ -60,7 +80,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_rings, inc_src],
-    dependencies: [py_dep, cysignals, flint, gmp, gmpxx],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modular/arithgroup',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/modular/modform/meson.build b/src/sage/modular/modform/meson.build
index 541227d9511..de2d7543096 100644
--- a/src/sage/modular/modform/meson.build
+++ b/src/sage/modular/modform/meson.build
@@ -36,13 +36,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/modular/modform',
     install: true,
     include_directories: [inc_cpython, inc_flint, inc_rings],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modular/modform',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/modular/modsym/meson.build b/src/sage/modular/modsym/meson.build
index 15851710402..b343290ef6a 100644
--- a/src/sage/modular/modsym/meson.build
+++ b/src/sage/modular/modsym/meson.build
@@ -30,13 +30,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/modular/modsym',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_rings],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modular/modsym',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/modules/meson.build b/src/sage/modules/meson.build
index a5c78e98633..13b7ed9688d 100644
--- a/src/sage/modules/meson.build
+++ b/src/sage/modules/meson.build
@@ -62,6 +62,7 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp]
   py.extension_module(
     name,
     sources: pyx,
@@ -74,7 +75,7 @@ foreach name, pyx : extension_data
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [py_dep, cysignals, gd, gmp, m4ri, png],
+    dependencies: deps,
   )
 endforeach
 
@@ -84,6 +85,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gd, gmp, m4ri, png]
   py.extension_module(
     name,
     sources: pyx,
@@ -97,8 +99,26 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [py_dep, cysignals, gd, gmp, m4ri, png],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modules',
+      install: true,
+      copy: true,
+  )
+  endif
 endforeach
 
 install_subdir('fg_pid', install_dir: sage_install_dir / 'modules')
diff --git a/src/sage/modules/with_basis/meson.build b/src/sage/modules/with_basis/meson.build
index 7dc1dda551b..ff977fe782d 100644
--- a/src/sage/modules/with_basis/meson.build
+++ b/src/sage/modules/with_basis/meson.build
@@ -13,13 +13,32 @@ py.install_sources(
 extension_data = {'indexed_element' : files('indexed_element.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/modules/with_basis',
     install: true,
     include_directories: [inc_cpython, inc_data_structures],
-    dependencies: [py_dep, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'modules/with_basis',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/numerical/backends/meson.build b/src/sage/numerical/backends/meson.build
index 57eeaeb10b0..37b214431b4 100644
--- a/src/sage/numerical/backends/meson.build
+++ b/src/sage/numerical/backends/meson.build
@@ -41,14 +41,33 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, glpk, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/numerical/backends',
     install: true,
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, cysignals, glpk, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'numerical/backends',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {'scip_backend': files('scip_backend.pyx')}
diff --git a/src/sage/numerical/meson.build b/src/sage/numerical/meson.build
index 91257af0880..be252b148a3 100644
--- a/src/sage/numerical/meson.build
+++ b/src/sage/numerical/meson.build
@@ -23,14 +23,33 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cypari2, gmp, mpfr]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/numerical',
     install: true,
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, cypari2, gmp, mpfr],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'numerical',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 subdir('backends')
diff --git a/src/sage/plot/meson.build b/src/sage/plot/meson.build
index 8cb44114959..39fe4b25b13 100644
--- a/src/sage/plot/meson.build
+++ b/src/sage/plot/meson.build
@@ -36,14 +36,33 @@ py.install_sources(
 extension_data = {'complex_plot' : files('complex_plot.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gsl]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/plot',
     install: true,
     include_directories: [inc_cpython, inc_gsl, inc_numpy, inc_rings],
-    dependencies: [py_dep, cysignals, gmp, gsl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'plot',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 subdir('plot3d')
diff --git a/src/sage/plot/plot3d/meson.build b/src/sage/plot/plot3d/meson.build
index ae1dd2a6b41..41a93123b2a 100644
--- a/src/sage/plot/plot3d/meson.build
+++ b/src/sage/plot/plot3d/meson.build
@@ -31,9 +31,9 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
-  dependencies = [py_dep, cysignals, gmp]
+  deps = [py_dep, cysignals, gmp]
   if name == 'parametric_surface'
-    dependencies += [interpreters_dep]
+    deps += [interpreters_dep]
   endif
   py.extension_module(
     name,
@@ -41,6 +41,24 @@ foreach name, pyx : extension_data
     subdir: 'sage/plot/plot3d',
     install: true,
     include_directories: [inc_cpython, inc_ext, inc_numpy],
-    dependencies: dependencies,
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'plot/plot3d',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
diff --git a/src/sage/probability/meson.build b/src/sage/probability/meson.build
index 2981a7496c4..61dd82d20fb 100644
--- a/src/sage/probability/meson.build
+++ b/src/sage/probability/meson.build
@@ -10,13 +10,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, gmp, gsl]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/probability',
     install: true,
     include_directories: [],
-    dependencies: [py_dep, cysignals, gmp, gsl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'probability',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/convert/meson.build b/src/sage/rings/convert/meson.build
index 04b9e285593..a0750d2cc91 100644
--- a/src/sage/rings/convert/meson.build
+++ b/src/sage/rings/convert/meson.build
@@ -8,13 +8,32 @@ py.install_sources(
 extension_data = {'mpfi' : files('mpfi.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, gmp, gsl, mpfi, mpfr]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/rings/convert',
     install: true,
     include_directories: [inc_cpython, inc_rings],
-    dependencies: [py_dep, cypari2, gmp, gsl, mpfi, mpfr, pari],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/convert',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/finite_rings/meson.build b/src/sage/rings/finite_rings/meson.build
index 7e6c338636f..eda5754c4a8 100644
--- a/src/sage/rings/finite_rings/meson.build
+++ b/src/sage/rings/finite_rings/meson.build
@@ -63,6 +63,24 @@ foreach name, pyx : extension_data
     ],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/finite_rings',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -72,6 +90,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cypari2, cysignals, givaro, gmp, m, ntl, pari]
   py.extension_module(
     name,
     sources: pyx,
@@ -85,7 +104,25 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [py_dep, cypari2, cysignals, givaro, gmp, m, ntl, pari],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/finite_rings',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/imaginary_unit.py b/src/sage/rings/imaginary_unit.py
index ae78b38d6c8..d4790178848 100644
--- a/src/sage/rings/imaginary_unit.py
+++ b/src/sage/rings/imaginary_unit.py
@@ -1,4 +1,8 @@
 
+from sage.features import FeatureNotPresentError
 from sage.rings.number_field.number_field import GaussianField
 
-I = GaussianField().gen()
+try:
+    I = GaussianField().gen()
+except FeatureNotPresentError:
+    I = None # Needs NTL
diff --git a/src/sage/rings/meson.build b/src/sage/rings/meson.build
index 5f4dafdf7c2..4b2846aa463 100644
--- a/src/sage/rings/meson.build
+++ b/src/sage/rings/meson.build
@@ -176,6 +176,23 @@ foreach name, pyx : extension_data
     ],
     dependencies: deps,
   )
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -220,6 +237,23 @@ foreach name, pyx : extension_data_cpp
     ],
     dependencies: deps,
   )
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('asymptotic', install_dir: sage_install_dir / 'rings')
diff --git a/src/sage/rings/number_field/meson.build b/src/sage/rings/number_field/meson.build
index 5b612679d40..16c0d8fc15d 100644
--- a/src/sage/rings/number_field/meson.build
+++ b/src/sage/rings/number_field/meson.build
@@ -51,6 +51,24 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_ntl, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/number_field',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -59,6 +77,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cypari2, cysignals, flint, gmp, mpfi, mpfr, ntl]
   py.extension_module(
     name,
     sources: pyx,
@@ -66,7 +85,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_flint, inc_ntl, inc_rings],
-    dependencies: [py_dep, cypari2, cysignals, flint, gmp, mpfi, mpfr, ntl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/number_field',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/number_field/totallyreal_data.pyx b/src/sage/rings/number_field/totallyreal_data.pyx
index 694e96235bc..67727a078b4 100644
--- a/src/sage/rings/number_field/totallyreal_data.pyx
+++ b/src/sage/rings/number_field/totallyreal_data.pyx
@@ -30,9 +30,13 @@ from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing
 from sage.rings.real_mpfr import RealField
 from sage.rings.integer_ring import ZZ
 from sage.rings.integer cimport Integer
+from sage.features import FeatureNotPresentError
 
 # Other global variables
-ZZx = PolynomialRing(ZZ, 'x')
+try:
+    ZZx = PolynomialRing(ZZ, 'x')
+except FeatureNotPresentError:
+    ZZx = None
 
 from libc.math cimport lrint, floor, ceil, fabs, round
 
diff --git a/src/sage/rings/padics/meson.build b/src/sage/rings/padics/meson.build
index f589881042e..9430f5a68fc 100644
--- a/src/sage/rings/padics/meson.build
+++ b/src/sage/rings/padics/meson.build
@@ -88,6 +88,24 @@ foreach name, pyx : extension_data
     ],
     dependencies: [py_dep, cypari2, cysignals, flint, gmp, m, ntl],
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/padics',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -120,5 +138,23 @@ foreach name, pyx : extension_data_cpp
     ],
     dependencies: [py_dep, cypari2, cysignals, flint, gmp, m, ntl],
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/padics',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/polynomial/meson.build b/src/sage/rings/polynomial/meson.build
index a74efed061a..4c4b7905c09 100644
--- a/src/sage/rings/polynomial/meson.build
+++ b/src/sage/rings/polynomial/meson.build
@@ -123,6 +123,24 @@ foreach name, pyx : extension_data
     ],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/polynomial',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 extension_data_cpp = {
@@ -157,20 +175,26 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       inc_rings_finite,
     ],
-    dependencies: [
-      py_dep,
-      cypari2,
-      cysignals,
-      flint,
-      givaro,
-      gmp,
-      mpfi,
-      mpfr,
-      ntl,
-      pari,
-      singular,
-    ],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/polynomial',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('padics', install_dir: sage_install_dir / 'rings/polynomial')
diff --git a/src/sage/rings/polynomial/pbori/meson.build b/src/sage/rings/polynomial/pbori/meson.build
index c7541ae492d..891ca95967d 100644
--- a/src/sage/rings/polynomial/pbori/meson.build
+++ b/src/sage/rings/polynomial/pbori/meson.build
@@ -29,6 +29,7 @@ py.install_sources(
 extension_data_cpp = {'pbori': files('pbori.pyx')}
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, brial, brial_groebner, cysignals, gmp, m4ri, png]
   py.extension_module(
     name,
     sources: pyx,
@@ -36,7 +37,25 @@ foreach name, pyx : extension_data_cpp
     install: true,
     override_options: ['cython_language=cpp'],
     include_directories: [inc_cpython, inc_ext, inc_rings, inc_src],
-    dependencies: [py_dep, brial, brial_groebner, cysignals, gmp, m4ri, png],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/polynomial/pbori',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/polynomial/polynomial_ring.py b/src/sage/rings/polynomial/polynomial_ring.py
index 82d8eae3361..60e770146f8 100644
--- a/src/sage/rings/polynomial/polynomial_ring.py
+++ b/src/sage/rings/polynomial/polynomial_ring.py
@@ -141,6 +141,7 @@
 
 import sys
 
+from sage.features.mock import MockInstance
 from sage.misc.superseded import deprecation
 from sage.structure.element import Element
 from sage.structure.category_object import check_default_category
@@ -2192,11 +2193,9 @@ def _element_class():
                 from sage.rings.polynomial.polynomial_element_generic import Polynomial_generic_sparse_field
                 return Polynomial_generic_sparse_field
             if isinstance(base_ring, rational_field.RationalField):
-                try:
-                    from sage.rings.polynomial.polynomial_rational_flint import Polynomial_rational_flint
+                from sage.rings.polynomial.polynomial_rational_flint import Polynomial_rational_flint
+                if not isinstance(Polynomial_rational_flint, MockInstance):
                     return Polynomial_rational_flint
-                except ImportError:
-                    pass
             elif isinstance(base_ring, NumberField):
                 if base_ring.is_absolute():
                     from sage.rings.polynomial.polynomial_number_field import Polynomial_absolute_number_field_dense
@@ -2205,17 +2204,13 @@ def _element_class():
                     from sage.rings.polynomial.polynomial_number_field import Polynomial_relative_number_field_dense
                     return Polynomial_relative_number_field_dense
             elif isinstance(base_ring, sage.rings.abc.RealField):
-                try:
-                    from .polynomial_real_mpfr_dense import PolynomialRealDense
+                from sage.rings.polynomial.polynomial_real_mpfr_dense import PolynomialRealDense
+                if not isinstance(PolynomialRealDense, MockInstance):
                     return PolynomialRealDense
-                except ImportError:
-                    pass
             elif isinstance(base_ring, sage.rings.abc.ComplexBallField):
-                try:
-                    from sage.rings.polynomial.polynomial_complex_arb import Polynomial_complex_arb
+                from sage.rings.polynomial.polynomial_complex_arb import Polynomial_complex_arb
+                if not isinstance(Polynomial_complex_arb, MockInstance):
                     return Polynomial_complex_arb
-                except ImportError:
-                    pass
             from sage.rings.polynomial.polynomial_element_generic import Polynomial_generic_dense_field
             return Polynomial_generic_dense_field
 
diff --git a/src/sage/rings/polynomial/polynomial_ring_constructor.py b/src/sage/rings/polynomial/polynomial_ring_constructor.py
index 78074c8a1d2..89082198702 100644
--- a/src/sage/rings/polynomial/polynomial_ring_constructor.py
+++ b/src/sage/rings/polynomial/polynomial_ring_constructor.py
@@ -21,6 +21,7 @@
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
 
+from sage.features import FeatureNotPresentError
 from sage.structure.category_object import normalize_names
 
 try:
@@ -852,7 +853,7 @@ def _multi_variate(base_ring, names, sparse=None, order='degrevlex', implementat
         try:
             from sage.rings.polynomial.multi_polynomial_libsingular import MPolynomialRing_libsingular
             R = MPolynomialRing_libsingular(base_ring, n, names, order)
-        except (ImportError, TypeError, NotImplementedError):
+        except FeatureNotPresentError:
             if implementation is not None:
                 raise
         else:
diff --git a/src/sage/rings/polynomial/weil/meson.build b/src/sage/rings/polynomial/weil/meson.build
index 77432ffef30..aa0e3ce2aaa 100644
--- a/src/sage/rings/polynomial/weil/meson.build
+++ b/src/sage/rings/polynomial/weil/meson.build
@@ -8,13 +8,32 @@ py.install_sources(
 extension_data = {'weil_polynomials' : files('weil_polynomials.pyx')}
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cysignals, flint, gmp]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/rings/polynomial/weil',
     install: true,
     include_directories: [inc_cpython, inc_flint, inc_rings, inc_src],
-    dependencies: [py_dep, cysignals, flint, gmp],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'rings/polynomial/weil',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/rings/real_double.pyx b/src/sage/rings/real_double.pyx
index 5efa0c87b65..1468bca3c3a 100644
--- a/src/sage/rings/real_double.pyx
+++ b/src/sage/rings/real_double.pyx
@@ -54,6 +54,7 @@ import sage.arith.misc
 import sage.rings.integer
 import sage.rings.rational
 
+from sage.features import FeatureNotPresentError
 from sage.rings.integer cimport Integer
 from sage.rings.integer_ring import ZZ
 
@@ -2080,10 +2081,9 @@ cdef RealDoubleElement global_dummy_element
 
 try:
     from sage.rings.real_double_element_gsl import RealDoubleElement_gsl
-except ImportError:
-    global_dummy_element = RealDoubleElement(0)
-else:
     global_dummy_element = RealDoubleElement_gsl(0)
+except FeatureNotPresentError:
+    global_dummy_element = RealDoubleElement(0)
 
 # A global pool for performance when elements are rapidly created and destroyed.
 # It operates on the following principles:
diff --git a/src/sage/rings/species.py b/src/sage/rings/species.py
index 494e7020331..abe832d0f16 100644
--- a/src/sage/rings/species.py
+++ b/src/sage/rings/species.py
@@ -44,6 +44,7 @@
 from sage.combinat.integer_vector import IntegerVectors
 from sage.combinat.partition import Partitions, _Partitions
 from sage.combinat.sf.sf import SymmetricFunctions
+from sage.features import FeatureNotPresentError
 from sage.groups.perm_gps.constructor import PermutationGroupElement
 from sage.groups.perm_gps.permgroup import PermutationGroup, PermutationGroup_generic
 from sage.groups.perm_gps.permgroup_named import SymmetricGroup
@@ -66,8 +67,10 @@
 from sage.structure.unique_representation import (UniqueRepresentation,
                                                   WithPicklingByInitArgs)
 
-GAP_FAIL = libgap.eval('fail')
-
+try:
+    GAP_FAIL = libgap.eval('fail')
+except FeatureNotPresentError:
+    GAP_FAIL = None
 
 class AtomicSpeciesElement(WithEqualityById,
                            Element,
diff --git a/src/sage/schemes/elliptic_curves/meson.build b/src/sage/schemes/elliptic_curves/meson.build
index b2a3dda08c9..314107fdd4d 100644
--- a/src/sage/schemes/elliptic_curves/meson.build
+++ b/src/sage/schemes/elliptic_curves/meson.build
@@ -61,13 +61,32 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cypari2, cysignals, flint, gmp, mpfr, pari]
   py.extension_module(
     name,
     sources: pyx,
     subdir: 'sage/schemes/elliptic_curves',
     install: true,
     include_directories: [inc_cpython, inc_flint, inc_numpy, inc_rings],
-    dependencies: [py_dep, cypari2, cysignals, flint, gmp, mpfr, pari],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'schemes/elliptic_curves',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/schemes/hyperelliptic_curves/meson.build b/src/sage/schemes/hyperelliptic_curves/meson.build
index 170d08baaca..161682369b5 100644
--- a/src/sage/schemes/hyperelliptic_curves/meson.build
+++ b/src/sage/schemes/hyperelliptic_curves/meson.build
@@ -29,6 +29,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gmp, ntl]
   py.extension_module(
     name,
     sources: pyx,
@@ -43,7 +44,25 @@ foreach name, pyx : extension_data_cpp
       inc_rings_finite,
       inc_hypellfrob,
     ],
-    dependencies: [py_dep, cysignals, gmp, ntl],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'schemes/hyperelliptic_curves',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/stats/distributions/meson.build b/src/sage/stats/distributions/meson.build
index db152755b95..9cca09e04e0 100644
--- a/src/sage/stats/distributions/meson.build
+++ b/src/sage/stats/distributions/meson.build
@@ -19,6 +19,7 @@ extension_data = {
 }
 
 foreach name, pyx : extension_data
+  deps = [py_dep, cypari2, cysignals, gmp, mpfr]
   py.extension_module(
     name,
     sources: pyx,
@@ -26,7 +27,25 @@ foreach name, pyx : extension_data
     subdir: 'sage/stats/distributions',
     install: true,
     include_directories: [inc_cpython, inc_rings, inc_src],
-    dependencies: [py_dep, cypari2, cysignals, gmp, mpfr],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'stats/distributions',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
diff --git a/src/sage/structure/meson.build b/src/sage/structure/meson.build
index 9d0076ef53d..a9df9bca996 100644
--- a/src/sage/structure/meson.build
+++ b/src/sage/structure/meson.build
@@ -73,6 +73,24 @@ foreach name, pyx : extension_data
     include_directories: [inc_cpython, inc_ext, inc_rings],
     dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'structure',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('proof', install_dir: sage_install_dir / 'structure')
diff --git a/src/sage/structure/parent.pyx b/src/sage/structure/parent.pyx
index 1dd2ae070ca..6aebc84093a 100644
--- a/src/sage/structure/parent.pyx
+++ b/src/sage/structure/parent.pyx
@@ -127,6 +127,7 @@ from sage.structure.coerce_exceptions import CoercionException
 from sage.structure.coerce_maps cimport (NamedConvertMap, DefaultConvertMap,
                            DefaultConvertMap_unique, CallableConvertMap)
 from sage.structure.element cimport parent
+from sage.features.mock import MockInstance
 
 
 cdef _record_exception():
@@ -569,7 +570,10 @@ cdef class Parent(sage.structure.category_object.CategoryObject):
         inheritance from categories.
         """
         if not isinstance(cls, type):
-            raise TypeError(f"element class {cls!r} should be a type")
+            if isinstance(cls, MockInstance):
+                cls.raise_error()
+            else:
+                raise TypeError(f"element class {cls!r} should be a type")
         if inherit is None:
             inherit = (cls.__dictoffset__ != 0)
         if inherit:
diff --git a/src/sage/symbolic/meson.build b/src/sage/symbolic/meson.build
index fc1f2a806e3..b4d90ef43e0 100644
--- a/src/sage/symbolic/meson.build
+++ b/src/sage/symbolic/meson.build
@@ -109,6 +109,7 @@ extension_data_cpp = {
 }
 
 foreach name, pyx : extension_data_cpp
+  deps = [py_dep, cysignals, gmp, gsl, flint, singular_factory]
   py.extension_module(
     name,
     sources: pyx,
@@ -125,8 +126,26 @@ foreach name, pyx : extension_data_cpp
       inc_rings,
       include_directories('../libs/gmp'),
     ],
-    dependencies: [py_dep, cysignals, gmp, gsl, singular],
+    dependencies: deps,
   )
+
+  all_deps_found = true
+  foreach dep : deps
+    if not dep.found()
+      all_deps_found = false
+      break
+    endif
+  endforeach
+  if not all_deps_found
+    configure_file(
+      input: not_available,
+      output: name + '.py',
+      install_tag: 'python-runtime',
+      install_dir: sage_install_dir / 'symbolic',
+      install: true,
+      copy: true,
+    )
+  endif
 endforeach
 
 install_subdir('integration', install_dir: sage_install_dir / 'symbolic')