py: resolve module paths without executing modules

Signed-off-by: Filipe Laíns <[email protected]

pyproject.toml

@@ -109,6 +109,9 @@ extend-select = [
 lines-after-imports = 2
 lines-between-types = 1
 
+[tool.ruff.lint.per-file-ignores]
+'tests/packages/error-on-import/**' = ['TRY002', 'TRY003', 'EM101']
+
 [tool.coverage.run]
 source = [
   'pkgconf',

src/pkgconf/__init__.py

@@ -1,4 +1,4 @@
-import importlib
+import importlib.util
 import itertools
 import logging
 import operator
@@ -8,6 +8,8 @@
 import subprocess
 import sys
 import sysconfig
+import types
+import unittest.mock
 import warnings
 
 from typing import Any, Optional
@@ -67,9 +69,36 @@ def get_executable() -> pathlib.Path:
     raise RuntimeError(msg)
 
 
+def _import_module_no_exec(name: str) -> types.ModuleType:
+    """Return a module object with all the module attributes set, but without executing it."""
+    if name in sys.modules:
+        return sys.modules[name]
+    # Import parent
+    if parent := name.rpartition('.')[0]:
+        _import_module_no_exec(parent)
+    # Find spec
+    spec = importlib.util.find_spec(name)
+    if not spec:
+        msg = f'No module named {name!r}'
+        raise ModuleNotFoundError(msg)
+    # Create module object without executing
+    module = importlib.util.module_from_spec(spec)
+    # Save to sys/modules
+    sys.modules[name] = module
+    return module
+
+
 def _get_module_paths(name: str) -> Sequence[str]:
-    module = importlib.import_module(name)
-    return list(module.__path__)
+    try:
+        with unittest.mock.patch.dict('sys.modules', sys.modules.copy()):
+            module = _import_module_no_exec(name)
+            if not hasattr(module, '__path__'):
+                warnings.warn(f"{module} isn't a package, it won't be added to PKG_CONFIG_PATH", stacklevel=2)
+                return []
+            return list(module.__path__)
+    except Exception:
+        _LOGGER.exception(f'Failed to find paths for module {name!r}')
+        return []
 
 
 def get_pkg_config_path() -> Sequence[str]:

tests/packages/error-on-import/foo/__init__.py

@@ -0,0 +1 @@
+raise Exception('Error during import :(')

tests/packages/error-on-import/foo/bar/__init__.py

@@ -0,0 +1 @@
+raise Exception('Error during import :(')

tests/packages/error-on-import/meson.build

@@ -0,0 +1,5 @@
+project('error-on-import', 'c', version: '1.0.0')
+
+py = import('python').find_installation()
+py.install_sources('foo/__init__.py', subdir: 'foo')
+py.install_sources('foo/bar/__init__.py', subdir: 'foo/bar')

tests/packages/error-on-import/pyproject.toml

@@ -0,0 +1,11 @@
+[build-system]
+build-backend = 'mesonpy'
+requires = ['meson-python']
+
+[project]
+name = 'error-on-import'
+version = '1.0.0'
+
+[project.entry-points.pkg_config]
+error-on-import-foo = 'foo'
+error-on-import-bar = 'foo.bar'

tests/test_python_module.py

@@ -38,6 +38,17 @@ def test_pkg_config_path_namespace(env, packages):
     assert path == [pathlib.Path(env.scheme['purelib'], 'namespace')]
 
 
+def test_pkg_config_path_error_on_import(env, packages):
+    path = list(env.introspectable.call('pkgconf.get_pkg_config_path'))
+    assert len(path) == 0
+
+    env.install_from_path(packages / 'error-on-import', from_sdist=False)
+    env_site_dir = pathlib.Path(env.scheme['purelib'])
+
+    path = set(map(pathlib.Path, env.introspectable.call('pkgconf.get_pkg_config_path')))
+    assert path == {env_site_dir / 'foo', env_site_dir / 'foo' / 'bar'}
+
+
 def test_run_pkgconfig(env):
     output = env.introspectable.call('pkgconf.run_pkgconf', '--help', capture_output=True)
     assert output.stdout.decode().startswith('usage: pkgconf')