Change Bazel XML support to depend upon BAZEL_TEST

docs/configuration.md

@@ -98,11 +98,13 @@ is equivalent with the out-of-the-box experience.
 
 
 ## Bazel support
-When `CATCH_CONFIG_BAZEL_SUPPORT` is defined, Catch2 will register a `JUnit`
-reporter writing to a path pointed by `XML_OUTPUT_FILE` provided by Bazel.
+When `CATCH_CONFIG_BAZEL_SUPPORT` is defined or when `BAZEL_TEST=1` (which is set by the Bazel inside of a test environment), 
+Catch2 will register a `JUnit` reporter writing to a path pointed by `XML_OUTPUT_FILE` provided by Bazel.
 
 > `CATCH_CONFIG_BAZEL_SUPPORT` was [introduced](https://github.com/catchorg/Catch2/pull/2399) in Catch2 3.0.1.
 
+> `CATCH_CONFIG_BAZEL_SUPPORT` was [deprecated](https://github.com/catchorg/Catch2/pull/2459) in Catch2 X.Y.Z.
+
 ## C++11 toggles
 
     CATCH_CONFIG_CPP11_TO_STRING // Use `std::to_string`

docs/deprecations.md

@@ -17,6 +17,15 @@ as it can be replaced by `Catch.cmake` that provides the function
 command line interface instead of parsing C++ code with regular expressions.
 
 
+### `CATCH_CONFIG_BAZEL_SUPPORT`
+
+Catch2 supports writing the Bazel JUnit XML output file when it is aware
+that is within a bazel testing environment. Originally there was no way
+to accurately probe the environment for this information so the flag
+`CATCH_CONFIG_BAZEL_SUPPORT` was added. This now deprecated. Bazel has now had a change
+where it will export `BAZEL_TEST=1` for purposes like the above. Catch2
+will now instead inspect the environment instead of relying on build configuration.
+
 ---
 
 [Home](Readme.md#top)

src/catch2/catch_config.cpp

@@ -15,6 +15,9 @@
 
 namespace Catch {
 
+    // Requires declaration for -Wmissing-declarations.
+    bool provideBazelReporterOutput();
+
     bool operator==( ProcessedReporterSpec const& lhs,
                      ProcessedReporterSpec const& rhs ) {
         return lhs.name == rhs.name &&
@@ -59,27 +62,27 @@ namespace Catch {
             } );
         }
 
-#if defined( CATCH_CONFIG_BAZEL_SUPPORT )
-        // Register a JUnit reporter for Bazel. Bazel sets an environment
-        // variable with the path to XML output. If this file is written to
-        // during test, Bazel will not generate a default XML output.
-        // This allows the XML output file to contain higher level of detail
-        // than what is possible otherwise.
+    if(provideBazelReporterOutput()){
+            // Register a JUnit reporter for Bazel. Bazel sets an environment
+            // variable with the path to XML output. If this file is written to
+            // during test, Bazel will not generate a default XML output.
+            // This allows the XML output file to contain higher level of detail
+            // than what is possible otherwise.
 #    if defined( _MSC_VER )
-        // On Windows getenv throws a warning as there is no input validation,
-        // since the key is hardcoded, this should not be an issue.
-#        pragma warning( push )
-#        pragma warning( disable : 4996 )
+            // On Windows getenv throws a warning as there is no input validation,
+            // since the key is hardcoded, this should not be an issue.
+#           pragma warning( push )
+#           pragma warning( disable : 4996 )
 #    endif
-        const auto bazelOutputFilePtr = std::getenv( "XML_OUTPUT_FILE" );
+            const auto bazelOutputFilePtr = std::getenv( "XML_OUTPUT_FILE" );
 #    if defined( _MSC_VER )
 #        pragma warning( pop )
 #    endif
-        if ( bazelOutputFilePtr != nullptr ) {
-            m_data.reporterSpecifications.push_back(
-                { "junit", std::string( bazelOutputFilePtr ), {}, {} } );
-        }
-#endif
+            if ( bazelOutputFilePtr != nullptr ) {
+                m_data.reporterSpecifications.push_back(
+                    { "junit", std::string( bazelOutputFilePtr ), {}, {} } );
+            }
+    }
 
 
         // We now fixup the reporter specs to handle default output spec,
@@ -113,6 +116,26 @@ namespace Catch {
     bool Config::listReporters() const      { return m_data.listReporters; }
     bool Config::listListeners() const      { return m_data.listListeners; }
 
+    bool provideBazelReporterOutput() {
+#ifdef CATCH_CONFIG_BAZEL_SUPPORT
+        return true;
+#else
+
+#    if defined( _MSC_VER )
+        // On Windows getenv throws a warning as there is no input validation,
+        // since the switch is hardcoded, this should not be an issue.
+#        pragma warning( push )
+#       pragma warning( disable : 4996 )
+#    endif
+
+    return std::getenv("BAZEL_TEST") != nullptr;
+
+#    if defined( _MSC_VER )
+#        pragma warning( pop )
+#    endif
+#endif
+    }
+
     std::vector<std::string> const& Config::getTestsOrTags() const { return m_data.testsOrTags; }
     std::vector<std::string> const& Config::getSectionsToRun() const { return m_data.sectionsToRun; }
 

tests/ExtraTests/CMakeLists.txt

@@ -137,6 +137,18 @@ set_tests_properties(CATCH_CONFIG_BAZEL_REPORTER-1
     LABELS "uses-python"
 )
 
+# We must now test this works without the build flag.
+add_executable( BazelReporterNoCatchConfig ${TESTS_DIR}/X30-BazelReporter.cpp )
+target_link_libraries(BazelReporterNoCatchConfig Catch2WithMain)
+add_test(NAME NO_CATCH_CONFIG_BAZEL_REPORTER-1
+  COMMAND
+  "${PYTHON_EXECUTABLE}" "${CATCH_DIR}/tests/TestScripts/testBazelReporter.py" $<TARGET_FILE:BazelReporterNoCatchConfig> "${CMAKE_CURRENT_BINARY_DIR}"
+)
+set_tests_properties(NO_CATCH_CONFIG_BAZEL_REPORTER-1
+  PROPERTIES
+    LABELS "uses-python"
+    ENVIRONMENT "BAZEL_TEST=1"
+)
 
 # The default handler on Windows leads to the just-in-time debugger firing,
 # which makes this test unsuitable for CI and headless runs, as it opens