logging

Author: jacobtylerwalls

ChangeLog

@@ -15,6 +15,9 @@ Release date: TBA
 
   Closes #1512
 
+* Capture and log messages emitted by C extensions when importing them.
+  This prevents contaminating programmatic output, e.g. pylint's JSON reporter.
+
 * Pipe stdout to stderr when importing C modules. This prevents contaminating programmatic output,
   e.g. pylint's JSON reporter.
 

astroid/manager.py

@@ -10,9 +10,12 @@
 from __future__ import annotations
 
 import collections
+import io
+import logging
 import os
 import types
 import zipimport
+from contextlib import redirect_stderr, redirect_stdout
 from importlib.util import find_spec, module_from_spec
 from typing import TYPE_CHECKING, ClassVar
 
@@ -39,6 +42,9 @@
 ZIP_IMPORT_EXTS = (".zip", ".egg", ".whl", ".pyz", ".pyzw")
 
 
+logger = logging.getLogger(__name__)
+
+
 def safe_repr(obj):
     try:
         return repr(obj)
@@ -173,13 +179,27 @@ def ast_from_module_name(self, modname, context_file=None):
                 ):
                     return self._build_stub_module(modname)
                 try:
-                    module = load_module_from_name(modname)
+                    # Capture and log anything emitted during import to avoid
+                    # contaminating JSON reports in pylint
+                    with redirect_stderr(io.StringIO()) as stderr, redirect_stdout(
+                        io.StringIO()
+                    ) as stdout:
+                        module = load_module_from_name(modname)
                 except Exception as e:
                     raise AstroidImportError(
                         "Loading {modname} failed with:\n{error}",
                         modname=modname,
                         path=found_spec.location,
                     ) from e
+                if stderr.getvalue():
+                    logger.error(
+                        f"Captured stderr from importing {modname}:\n{stdout.getvalue()}"
+                    )
+                if stdout.getvalue():
+                    logger.info(
+                        f"Captured stdout from importing {modname}:\n{stdout.getvalue()}"
+                    )
+
                 return self.ast_from_module(module, modname)
 
             elif found_spec.type == spec.ModuleType.PY_COMPILED:

astroid/modutils.py

@@ -171,15 +171,7 @@ def load_module_from_name(dotted_name: str) -> types.ModuleType:
     except KeyError:
         pass
 
-    # Pipe stdout to stderr to avoid contaminating programmatic output,
-    # e.g. JSON reports in pylint
-    original_stdout = sys.stdout
-    sys.stdout = sys.stderr
-    try:
-        module = importlib.import_module(dotted_name)
-    finally:
-        sys.stdout = original_stdout
-    return module
+    return importlib.import_module(dotted_name)
 
 
 def load_module_from_modpath(parts):

requirements_test.txt

@@ -5,7 +5,6 @@ coveralls~=3.3
 coverage~=6.3.3
 pre-commit~=2.19
 pytest-cov~=3.0
-contributors-txt>=0.7.3
 tbump~=6.9.0
 types-typed-ast; implementation_name=="cpython" and python_version<"3.8"
 types-pkg_resources==0.1.3

tests/unittest_modutils.py

@@ -16,8 +16,6 @@
 from xml import etree
 from xml.etree import ElementTree
 
-from pytest import CaptureFixture
-
 import astroid
 from astroid import modutils
 from astroid.interpreter._import import spec
@@ -368,20 +366,6 @@ def test_load_module_set_attribute(self) -> None:
         self.assertTrue(m is xml.etree.ElementTree)
 
 
-def test_stdout_piped_to_stderr_during_c_module_import(capsys: CaptureFixture) -> None:
-    del xml.etree.ElementTree
-    del sys.modules["xml.etree.ElementTree"]
-
-    with unittest.mock.patch("importlib.import_module", side_effect=print):
-        # This string argument will also be sent to the print() side_effect
-        modutils.load_module_from_name("xml.etree.ElementTree")
-
-    outerr = capsys.readouterr()
-    assert outerr.out == ""
-    # Message is preserved in stderr in case useful
-    assert outerr.err.strip() == "xml.etree.ElementTree"
-
-
 class ExtensionPackageWhitelistTest(unittest.TestCase):
     def test_is_module_name_part_of_extension_package_whitelist_true(self) -> None:
         """Test that the is_module_name_part_of_extension_package_whitelist function returns True when needed"""