[libclang/python] Add LIBCLANG_LIBRARY_PATH and LIBCLANG_LIBRARY_FILE

clang/bindings/python/README.txt

@@ -4,12 +4,12 @@
 
 This directory implements Python bindings for Clang.
 
-You may need to set CLANG_LIBRARY_PATH so that the Clang library can be
+You may need to set LIBCLANG_LIBRARY_PATH so that the Clang library can be
 found. The unit tests are designed to be run with any standard test
 runner. For example:
 --
 $ env PYTHONPATH=$(echo ~/llvm/clang/bindings/python/) \
-      CLANG_LIBRARY_PATH=$(llvm-config --libdir) \
+      LIBCLANG_LIBRARY_PATH=$(llvm-config --libdir) \
   python3 -m unittest discover -v
 tests.cindex.test_index.test_create ... ok
 ...

clang/bindings/python/clang/cindex.py

@@ -4383,8 +4383,8 @@ def register(item: LibFunc) -> None:
 
 
 class Config:
-    library_path = None
-    library_file: str | None = None
+    library_path: str | None = os.environ.get("LIBCLANG_LIBRARY_PATH")
+    library_file: str | None = os.environ.get("LIBCLANG_LIBRARY_FILE")
     compatibility_check = True
     loaded = False
 
@@ -4468,10 +4468,11 @@ def get_cindex_library(self) -> CDLL:
         try:
             library = cdll.LoadLibrary(self.get_filename())
         except OSError as e:
-            msg = (
-                str(e) + ". To provide a path to libclang use "
-                "Config.set_library_path() or "
-                "Config.set_library_file()."
+            msg = str(e) + (
+                "To provide the path to libclang, you can use the environment variable "
+                "LIBCLANG_LIBRARY_PATH or call Config.set_library_path(). "
+                "Alternatively, you can specify the exact library file using "
+                "LIBCLANG_LIBRARY_FILE or Config.set_library_file()."
             )
             raise LibclangError(msg)
 

clang/bindings/python/tests/CMakeLists.txt

@@ -5,7 +5,7 @@
 add_custom_target(check-clang-python
     COMMAND ${CMAKE_COMMAND} -E env
             CLANG_NO_DEFAULT_CONFIG=1
-            CLANG_LIBRARY_PATH=$<TARGET_FILE_DIR:libclang>
+            LIBCLANG_LIBRARY_PATH=$<TARGET_FILE_DIR:libclang>
             "${Python3_EXECUTABLE}" -m unittest discover
     DEPENDS libclang
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/..)

clang/bindings/python/tests/cindex/test_access_specifiers.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import AccessSpecifier, Config
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_cdb.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import CompilationDatabase, CompilationDatabaseError, Config
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import gc
 import unittest

clang/bindings/python/tests/cindex/test_code_completion.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, TranslationUnit
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 from pathlib import Path

clang/bindings/python/tests/cindex/test_comment.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, TranslationUnit
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_cursor.py

@@ -15,8 +15,6 @@
     conf,
 )
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import gc
 import unittest

clang/bindings/python/tests/cindex/test_cursor_kind.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, CursorKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_cursor_language.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, LanguageKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_diagnostics.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, Diagnostic
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_environment_variable.py

@@ -0,0 +1,63 @@
+import unittest
+import unittest.mock
+import sys
+import os
+
+
+def reset_import_and_get_frech_config():
+    # Reloads the clang.cindex module to reset any class-level state in Config.
+    sys.modules.pop("clang.cindex", None)
+    sys.modules.pop("clang", None)
+    from clang.cindex import Config
+
+    return Config()
+
+
+class TestEnvironementVariable(unittest.TestCase):
+    def test_working_libclang_library_file(self):
+        ref_libclang_library_file = reset_import_and_get_frech_config().get_filename()
+        with unittest.mock.patch.dict(
+            os.environ, {"LIBCLANG_LIBRARY_FILE": ref_libclang_library_file}
+        ):
+            reset_import_and_get_frech_config().lib
+
+    @unittest.mock.patch.dict("os.environ", {"LIBCLANG_LIBRARY_FILE": "/dev/null"})
+    def test_non_working_libclang_library_file(self):
+        config = reset_import_and_get_frech_config()
+        import clang.cindex
+
+        with self.assertRaises(clang.cindex.LibclangError):
+            config.lib
+
+    def test_working_libclang_library_path(self):
+        # Get adequate libclang path
+        ref_libclang_library_file = reset_import_and_get_frech_config().get_filename()
+        ref_libclang_library_path, filename = os.path.split(ref_libclang_library_file)
+        filename_root, filename_ext = os.path.splitext(filename)
+
+        # Config only recognizes the default libclang filename.
+        # If LIBCLANG_LIBRARY_FILE points to a non-standard name, skip this test.
+
+        if not (
+            filename_root == "libclang" and filename_ext in (".so", ".dll", ".dylib")
+        ):
+            self.skipTest(f"Skipping because {filename} is not a default libclang name")
+
+        with unittest.mock.patch.dict(
+            os.environ, {"LIBCLANG_LIBRARY_PATH": ref_libclang_library_path}
+        ):
+            # Remove LIBCLANG_LIBRARY_FILE to avoid it taking precedence if set by the user
+            # Need to be in the mocked environement
+            os.environ.pop("LIBCLANG_LIBRARY_FILE", None)
+            reset_import_and_get_frech_config().lib
+
+    @unittest.mock.patch.dict("os.environ", {"LIBCLANG_LIBRARY_PATH": "not_a_real_dir"})
+    def test_non_working_libclang_library_path(self):
+        # Remove LIBCLANG_LIBRARY_FILE to avoid it taking precedence if set by the user
+        os.environ.pop("LIBCLANG_LIBRARY_FILE", None)
+
+        config = reset_import_and_get_frech_config()
+        import clang.cindex
+
+        with self.assertRaises(clang.cindex.LibclangError):
+            config.lib

clang/bindings/python/tests/cindex/test_exception_specification_kind.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, CursorKind, ExceptionSpecificationKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_file.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, File, Index, TranslationUnit
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_index.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, Index, TranslationUnit
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_lib.py

@@ -2,8 +2,6 @@
 
 import clang.cindex
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    clang.cindex.Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 import ast

clang/bindings/python/tests/cindex/test_linkage.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, LinkageKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_location.py

@@ -10,8 +10,6 @@
     TranslationUnit,
 )
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_source_range.py

@@ -3,8 +3,6 @@
 
 from clang.cindex import Config, SourceLocation, SourceRange, TranslationUnit
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_tls_kind.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, TLSKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_token_kind.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, TokenKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_tokens.py

@@ -2,8 +2,6 @@
 
 from clang.cindex import Config, CursorKind, SourceLocation, SourceRange, TokenKind
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import unittest
 

clang/bindings/python/tests/cindex/test_translation_unit.py

@@ -13,8 +13,6 @@
     TranslationUnitSaveError,
 )
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import gc
 import tempfile

clang/bindings/python/tests/cindex/test_type.py

@@ -10,8 +10,6 @@
     TypeKind,
 )
 
-if "CLANG_LIBRARY_PATH" in os.environ:
-    Config.set_library_path(os.environ["CLANG_LIBRARY_PATH"])
 
 import gc
 import unittest

clang/docs/ReleaseNotes.rst

@@ -170,6 +170,9 @@ Clang Python Bindings Potentially Breaking Changes
   ElaboratedTypes. The value becomes unused, and all the existing users should
   expect the former underlying type to be reported instead.
 - Remove ``AccessSpecifier.NONE`` kind. No libclang interfaces ever returned this kind.
+- Allow setting the path to the libclang library via environment variables: ``LIBCLANG_LIBRARY_PATH``
+  to specifiy the path to the folder, or ``LIBCLANG_LIBRARY_FILE`` to specify the path to
+  the library file
 
 What's New in Clang |release|?
 ==============================