Fix for UnboundLocalError in ensure_python SESSION_IS_INTERACTIVE=False (#6389)

* Fix for UnboundLocalError in ensure_python SESSION_IS_INTERACTIVE=False, using pyenv, and python version in Pipfile not available

* Add tests

* Add news

Author: matteius

news/6389.bugfix.rst

@@ -0,0 +1 @@
+Fix for ``UnboundLocalError`` in ``ensure_python`` when ``SESSION_IS_INTERACTIVE=False``, using pyenv, and python version in Pipfile not available.

pipenv/utils/virtualenv.py

@@ -306,21 +306,25 @@ def abort(msg=""):
             else:
                 abort("Neither 'pyenv' nor 'asdf' could be found to install Python.")
         else:
-            if environments.SESSION_IS_INTERACTIVE or project.s.PIPENV_YES:
-                try:
-                    version = installer.find_version_to_install(python)
-                except ValueError:
-                    abort()
-                except InstallerError as e:
-                    abort(f"Something went wrong while installing Python:\n{e.err}")
-                s = (
-                    "Would you like us to install ",
-                    f"[green]CPython {version}[/green] ",
-                    f"with {installer}?",
-                )
+            try:
+                version = installer.find_version_to_install(python)
+            except ValueError:
+                abort()
+            except InstallerError as e:
+                abort(f"Something went wrong while installing Python:\n{e.err}")
+
+            s = (
+                "Would you like us to install ",
+                f"[green]CPython {version}[/green] ",
+                f"with {installer}?",
+            )
 
             # Prompt the user to continue...
-            if not (project.s.PIPENV_YES or Confirm.ask("".join(s), default=True)):
+            if environments.SESSION_IS_INTERACTIVE:
+                if not (project.s.PIPENV_YES or Confirm.ask("".join(s), default=True)):
+                    abort()
+            elif not project.s.PIPENV_YES:
+                # Non-interactive session without PIPENV_YES, proceed with installation
                 abort()
             else:
                 # Tell the user we're installing Python.

tests/integration/test_python_version_mismatch.py

@@ -0,0 +1,103 @@
+import pytest
+
+from pipenv.utils.virtualenv import ensure_python
+
+
+def test_ensure_python_non_interactive_no_yes(monkeypatch, project):
+    """Test ensure_python when SESSION_IS_INTERACTIVE=False and PIPENV_YES=False."""
+    # Mock the environments.SESSION_IS_INTERACTIVE to be False
+    monkeypatch.setattr("pipenv.environments.SESSION_IS_INTERACTIVE", False)
+
+    # Mock project.s.PIPENV_YES to be False
+    monkeypatch.setattr(project.s, "PIPENV_YES", False)
+
+    # Mock find_version_to_install to return a version
+    class MockInstaller:
+        def __init__(self, *args, **kwargs):
+            self.cmd = "mock_installer"
+
+        def find_version_to_install(self, *args, **kwargs):
+            return "3.11.0"
+
+    monkeypatch.setattr("pipenv.installers.Pyenv", MockInstaller)
+
+    # Mock find_a_system_python to return None (Python not found)
+    monkeypatch.setattr("pipenv.utils.virtualenv.find_a_system_python", lambda x: None)
+
+    # Mock os.name to not be 'nt' to skip Windows-specific code
+    monkeypatch.setattr("os.name", "posix")
+
+    # Mock project.s.PIPENV_DONT_USE_PYENV to be False
+    monkeypatch.setattr(project.s, "PIPENV_DONT_USE_PYENV", False)
+
+    # The function should call sys.exit(1) when SESSION_IS_INTERACTIVE=False and PIPENV_YES=False
+    # We'll catch this with pytest.raises
+    with pytest.raises(SystemExit) as excinfo:
+        ensure_python(project, python="3.11.0")
+
+    # Verify that sys.exit was called with code 1
+    assert excinfo.value.code == 1
+
+
+def test_ensure_python_non_interactive_with_yes(monkeypatch, project):
+    """Test ensure_python when SESSION_IS_INTERACTIVE=False but PIPENV_YES=True."""
+    # Mock the environments.SESSION_IS_INTERACTIVE to be False
+    monkeypatch.setattr("pipenv.environments.SESSION_IS_INTERACTIVE", False)
+
+    # Mock project.s.PIPENV_YES to be True
+    monkeypatch.setattr(project.s, "PIPENV_YES", True)
+
+    # Mock find_version_to_install to return a version
+    class MockInstaller:
+        def __init__(self, *args, **kwargs):
+            self.cmd = "mock_installer"
+
+        def find_version_to_install(self, *args, **kwargs):
+            return "3.11.0"
+
+        def install(self, *args, **kwargs):
+            class Result:
+                stdout = "Installed successfully"
+            return Result()
+
+    monkeypatch.setattr("pipenv.installers.Pyenv", MockInstaller)
+
+    # Mock find_a_system_python to return None initially (Python not found)
+    # and then return a path after "installation"
+    find_python_calls = [None]
+
+    def mock_find_python(version):
+        if len(find_python_calls) == 1:
+            find_python_calls.append("/mock/path/to/python")
+            return find_python_calls[-1]
+        return find_python_calls[-1]
+
+    monkeypatch.setattr("pipenv.utils.virtualenv.find_a_system_python", mock_find_python)
+
+    # Mock python_version to return the expected version
+    monkeypatch.setattr("pipenv.utils.dependencies.python_version", lambda x: "3.11.0")
+
+    # Mock os.name to not be 'nt' to skip Windows-specific code
+    monkeypatch.setattr("os.name", "posix")
+
+    # Mock project.s.PIPENV_DONT_USE_PYENV to be False
+    monkeypatch.setattr(project.s, "PIPENV_DONT_USE_PYENV", False)
+
+    # Mock console.status to do nothing
+    def mock_status(*args, **kwargs):
+        class MockContextManager:
+            def __enter__(self):
+                return None
+
+            def __exit__(self, *args):
+                pass
+
+        return MockContextManager()
+
+    monkeypatch.setattr("pipenv.utils.console.status", mock_status)
+
+    # The function should proceed with installation when PIPENV_YES=True
+    result = ensure_python(project, python="3.11.0")
+
+    # Verify that the function returned the path to Python
+    assert result == "/mock/path/to/python"