arch: fix compiler sniff error handling

Fixed compiler version sniff and test

Added more information for failed MPI import

Carry mpi4py import error in dummy MPI class

Raised RuntimeError for missing compiler instead of sys.exit()

Fixed flake8 errors

Moved test to test_arch.py

benchmarks/user/benchmark.py

@@ -407,7 +407,7 @@ def test(problem, **kwargs):
                     "DEVITO_MPI is unset. Setting `DEVITO_MPI=basic`..."
                     % MPI.COMM_WORLD.size)
             configuration['mpi'] = 'basic'
-    except TypeError:
+    except (TypeError, ModuleNotFoundError):
         # MPI not available
         pass
 

devito/arch/compiler.py

@@ -6,7 +6,6 @@
                         check_call, run)
 import platform
 import warnings
-import sys
 import time
 
 import numpy.ctypeslib as npct
@@ -18,7 +17,7 @@
                          IntelDevice, get_nvidia_cc, check_cuda_runtime,
                          get_m1_llvm_path)
 from devito.exceptions import CompilationError
-from devito.logger import debug, warning, error
+from devito.logger import debug, warning
 from devito.parameters import configuration
 from devito.tools import (as_list, change_directory, filter_ordered,
                           memoized_func, make_tempdir)
@@ -42,12 +41,11 @@ def sniff_compiler_version(cc, allow_fail=False):
             return Version("0")
     except UnicodeDecodeError:
         return Version("0")
-    except FileNotFoundError:
+    except OSError:
         if allow_fail:
             return Version("0")
         else:
-            error("The `%s` compiler isn't available on this system" % cc)
-            sys.exit(1)
+            raise RuntimeError("The `%s` compiler isn't available on this system" % cc)
 
     if ver.startswith("gcc"):
         compiler = "gcc"

devito/mpi/distributed.py

@@ -42,13 +42,19 @@ def cleanup():
         if init_by_devito and MPI.Is_initialized() and not MPI.Is_finalized():
             MPI.Finalize()
     atexit.register(cleanup)
-except ImportError:
+except ImportError as e:
     # Dummy fallback in case mpi4py/MPI aren't available
     class NoneMetaclass(type):
         def __getattr__(self, name):
             return None
 
     class MPI(object, metaclass=NoneMetaclass):
+        init_error = e
+
+        @classmethod
+        def Init(cls):
+            raise cls.init_error
+
         @classmethod
         def Is_initialized(cls):
             return False

tests/test_arch.py

@@ -0,0 +1,12 @@
+import pytest
+
+from devito.arch.compiler import sniff_compiler_version
+
+
+@pytest.mark.parametrize("cc", [
+    "doesn'texist",
+    "/root/doesn'texist",
+])
+def test_sniff_compiler_version(cc):
+    with pytest.raises(RuntimeError, match=cc):
+        sniff_compiler_version(cc)