Merge ff20316ec972fff47c63c7c1eba18d83a9655e55 into 7140cd416cecd7462a8aae488024abeee55598e4

PiperOrigin-RevId: 925686474
Change-Id: I7b5d7e82dc8618d6914844446fa260468b947ece

.github/workflows/lint_python.yml

@@ -0,0 +1,11 @@
+# https://docs.github.com/en/actions
+# https://docs.github.com/en/actions/use-cases-and-examples/building-and-testing/building-and-testing-python
+# https://docs.astral.sh/ruff
+name: lint_python
+on: [pull_request, push]
+jobs:
+  lint_python:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: astral-sh/ruff-action@v3

docs/gmock_cook_book.md

@@ -3386,30 +3386,6 @@ With this definition, the above assertion will give a better message:
     Actual: 27 (the remainder is 6)
 ```
 
-#### Using EXPECT_ Statements in Matchers
-
-You can also use `EXPECT_...` statements inside custom matcher definitions. In
-many cases, this allows you to write your matcher more concisely while still
-providing an informative error message. For example:
-
-```cpp
-MATCHER(IsDivisibleBy7, "") {
-  const auto remainder = arg % 7;
-  EXPECT_EQ(remainder, 0);
-  return true;
-}
-```
-
-If you write a test that includes the line `EXPECT_THAT(27, IsDivisibleBy7());`,
-you will get an error something like the following:
-
-```shell
-Expected equality of these values:
-  remainder
-    Which is: 6
-  0
-```
-
 #### `MatchAndExplain`
 
 You should let `MatchAndExplain()` print *any additional information* that can
@@ -3429,6 +3405,66 @@ the value of `(arg % 7) == 0` can be implicitly converted to a `bool`. In the
 `arg_type` will be `int`; if it takes an `unsigned long`, `arg_type` will be
 `unsigned long`; and so on.
 
+#### Anti-pattern: Using EXPECT_ Statements in Matchers
+
+Using `EXPECT_...` statements inside custom matcher definitions is an
+**anti-pattern** and should be avoided.
+
+While it might appear to write matchers more concisely and generate informative
+messages, this pattern has critical issues:
+
+1.  **Negation Breakage (`Not`):** If wrapped in `Not(IsDivisibleBy7())`,
+    evaluating it still triggers the internal `EXPECT_EQ`, registering a test
+    failure on the runner even when the overall assertion is expected to
+    succeed.
+2.  **Composition / Container Breakage (`AnyOf`, `AllOf`, `Contains`):** When
+    composed or used inside container matchers, elements that are expected
+    mismatches will trigger the internal `EXPECT_` and register spurious
+    failures.
+3.  **ASSERT_* compilation errors:** `ASSERT_*` macros use `return;` to abort
+    from a void function. Since matchers return `bool`, using `ASSERT_` inside
+    them triggers a compilation error.
+4.  **Purity Violations:** Matchers must be functionally pure (side-effect
+    free), whereas registering global failures is a major side effect.
+5.  **Line Number Confusion:** Failure reports point to the matcher's definition
+    line rather than the calling `EXPECT_THAT`
+    line.
+
+##### The Anti-Pattern
+
+```cpp
+// Anti-pattern: Do not do this!
+MATCHER(IsDivisibleBy7, "") {
+  const auto remainder = arg % 7;
+  EXPECT_EQ(remainder, 0);  // Spurious failures if negated/composed!
+  return true;
+}
+```
+
+##### The Correct Solution
+
+To write concise matchers that delegate to other matchers and safely propagate
+the mismatch explanation, use **`::testing::ExplainMatchResult`** instead,
+passing it the sub-matcher, the value to check, and the `result_listener`:
+
+```cpp
+MATCHER(IsDivisibleBy7, "") {
+  const auto remainder = arg % 7;
+  return ::testing::ExplainMatchResult(::testing::Eq(0), remainder,
+                                       result_listener);
+}
+```
+
+If you write a test that includes the line:
+
+```cpp
+EXPECT_THAT(28, Not(IsDivisibleBy7()));
+```
+
+it will correctly report the mismatch, properly point to the `EXPECT_THAT` line
+number, and support negation (`Not`) and composition (`AllOf`, `AnyOf`, etc.)
+without registering spurious failures.
+
 ### Writing New Parameterized Matchers Quickly
 
 Sometimes you'll want to define a matcher that has parameters. For that you can

googlemock/include/gmock/gmock-spec-builders.h

@@ -1957,6 +1957,11 @@ struct SignatureOf<R(Args...)> {
   using type = R(Args...);
 };
 
+template <typename R, typename... Args>
+struct SignatureOf<R(Args...) const> {
+  using type = R(Args...);
+};
+
 template <template <typename> class C, typename F>
 struct SignatureOf<C<F>,
                    typename std::enable_if<std::is_function<F>::value>::type>

googlemock/test/gmock-function-mocker_test.cc

@@ -942,6 +942,15 @@ static constexpr bool IsMockFunctionTemplateArgumentDeducedTo(
 
 }  // namespace
 
+// Like std::add_const, but for function types.
+template <typename F>
+struct AddConstToFunction;
+
+template <typename R, typename... Args>
+struct AddConstToFunction<R(Args...)> {
+  using type = R(Args...) const;
+};
+
 template <typename F>
 class MockMethodMockFunctionSignatureTest : public Test {};
 
@@ -953,27 +962,71 @@ TYPED_TEST_SUITE(MockMethodMockFunctionSignatureTest,
 
 TYPED_TEST(MockMethodMockFunctionSignatureTest,
            IsMockFunctionTemplateArgumentDeducedForRawSignature) {
+  // Non-const
+  {
     using Argument = TypeParam;
     MockFunction<Argument> foo;
     EXPECT_TRUE(IsMockFunctionTemplateArgumentDeducedTo<TypeParam>(foo));
   }
 
+  // Const
+  {
+    using Argument = typename AddConstToFunction<TypeParam>::type;
+    MockFunction<Argument> foo;
+    EXPECT_TRUE(IsMockFunctionTemplateArgumentDeducedTo<TypeParam>(foo));
+  }
+}
+
 TYPED_TEST(MockMethodMockFunctionSignatureTest,
            IsMockFunctionTemplateArgumentDeducedForStdFunction) {
+  // Non-const
+  {
     using Argument = std::function<TypeParam>;
     MockFunction<Argument> foo;
     EXPECT_TRUE(IsMockFunctionTemplateArgumentDeducedTo<TypeParam>(foo));
   }
 
+// As of 2026-05 MSVC doesn't know how to deal with this, providing pages of
+// inscrutable errors about std::_Get_function_impl. But this is fine, since
+// std::function<R(Args...) const> doesn't apply the const qualifier correctly
+// anyway.
+#if !defined(_MSC_VER)
+
+  // Const
+  {
+    using Argument =
+        std::function<typename AddConstToFunction<TypeParam>::type>;
+
+    MockFunction<Argument> foo;
+    EXPECT_TRUE(IsMockFunctionTemplateArgumentDeducedTo<TypeParam>(foo));
+  }
+
+#endif
+}
+
 TYPED_TEST(
     MockMethodMockFunctionSignatureTest,
     IsMockFunctionCallMethodSignatureTheSameForRawSignatureAndStdFunction) {
+  // Non-const
+  {
     using ForRawSignature = decltype(&MockFunction<TypeParam>::Call);
     using ForStdFunction =
         decltype(&MockFunction<std::function<TypeParam>>::Call);
     EXPECT_TRUE((std::is_same<ForRawSignature, ForStdFunction>::value));
   }
 
+  // Const
+  {
+    using ConstTypeParam = typename AddConstToFunction<TypeParam>::type;
+    using ForRawSignature = decltype(&MockFunction<ConstTypeParam>::Call);
+
+    using ForStdFunction =
+        decltype(&MockFunction<std::function<ConstTypeParam>>::Call);
+
+    EXPECT_TRUE((std::is_same<ForRawSignature, ForStdFunction>::value));
+  }
+}
+
 template <typename F>
 struct AlternateCallable {};
 

googletest/include/gtest/gtest-message.h

@@ -129,7 +129,7 @@ class GTEST_API_ Message {
                               int>::type = 0
 #endif  // GTEST_HAS_ABSL
       >
-  inline Message& operator<<(const T& val) {
+  Message& operator<<(const T& val) {
         // Some libraries overload << for STL containers.  These
     // overloads are defined in the global namespace instead of ::std.
     //
@@ -155,7 +155,7 @@ class GTEST_API_ Message {
   template <typename T,
             typename std::enable_if<absl::HasAbslStringify<T>::value,  // NOLINT
                                     int>::type = 0>
-  inline Message& operator<<(const T& val) {
+  Message& operator<<(const T& val) {
     // ::operator<< is needed here for a similar reason as with the non-Abseil
     // version above
     using ::operator<<;

googletest/include/gtest/internal/gtest-death-test-internal.h

@@ -229,7 +229,8 @@ GTEST_API_ bool ExitedUnsuccessfully(int exit_status);
       goto GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__);                        \
     }                                                                          \
     if (gtest_dt != nullptr) {                                                 \
-      std::unique_ptr< ::testing::internal::DeathTest> gtest_dt_ptr(gtest_dt); \
+      const std::unique_ptr< ::testing::internal::DeathTest> gtest_dt_ptr(     \
+          gtest_dt);                                                           \
       switch (gtest_dt->AssumeRole()) {                                        \
         case ::testing::internal::DeathTest::OVERSEE_TEST:                     \
           if (!gtest_dt->Passed(predicate(gtest_dt->Wait()))) {                \

googletest/test/googletest-filter-unittest.py

@@ -714,7 +714,7 @@ class GTestFilterUnitTest(gtest_test_utils.TestCase):
 
   def testDisabledBanner(self):
     """Tests that the disabled banner prints only tests that match filter."""
-    make_filter = lambda s: ['--%s=%s' % (FILTER_FLAG, s)]
+    make_filter = lambda s: ['--%s=%s' % (FILTER_FLAG, s)]  # noqa: E731
 
     banners = RunAndExtractDisabledBannerList(make_filter('*'))
     self.AssertSetEqual(

googletest/test/googletest-shuffle-test.py

@@ -119,7 +119,7 @@ def GetTestCases(tests):
   test_cases = []
   for test in tests:
     test_case = test.split('.')[0]
-    if not test_case in test_cases:
+    if test_case not in test_cases:
       test_cases.append(test_case)
 
   return test_cases

googletest/test/gtest_test_utils.py

@@ -31,20 +31,18 @@
 # Suppresses the 'Import not at the top of the file' lint complaint.
 # pylint: disable=g-import-not-at-top
 
+import atexit
 import os
+import shutil
 import subprocess
 import sys
+import tempfile
+import unittest as _test_module
 
 IS_WINDOWS = os.name == 'nt'
 IS_CYGWIN = os.name == 'posix' and 'CYGWIN' in os.uname()[0]
 IS_OS2 = os.name == 'os2'
 
-import atexit
-import shutil
-import tempfile
-import unittest as _test_module
-# pylint: enable=g-import-not-at-top
-
 GTEST_OUTPUT_VAR_NAME = 'GTEST_OUTPUT'
 
 # The environment variable for specifying the path to the premature-exit file.

googletest/test/gtest_xml_outfiles_test.py

@@ -32,7 +32,7 @@
 """Unit test for the gtest_xml_output module."""
 
 import os
-from xml.dom import minidom, Node
+from xml.dom import minidom
 from googletest.test import gtest_test_utils
 from googletest.test import gtest_xml_test_utils
 

googletest/test/gtest_xml_test_utils.py

@@ -30,7 +30,7 @@
 """Unit test utilities for gtest_xml_output"""
 
 import re
-from xml.dom import minidom, Node
+from xml.dom import Node
 from googletest.test import gtest_test_utils
 
 GTEST_DEFAULT_OUTPUT_FILE = 'test_detail.xml'