GoogleTest: Rename TIMEOUT parameter to avoid clash

In gtest_discover_tests(), the TIMEOUT keyword was making it
impossible to set the TIMEOUT test property via the PROPERTIES
keyword. This would be a frequent case, but it doesn't complain
and instead silently does something different to what would
normally be expected. The TIMEOUT keyword has been renamed
to DISCOVERY_TIMEOUT, thereby removing the clash.

This is a breaking change. 3.10.1 and 3.10.2 were the only versions
that supported the TIMEOUT keyword and uses of it were likely
not working as intended.

Fixes: #17801

Help/release/3.10.rst

@@ -139,7 +139,8 @@ Modules
   This is robust against unusual ways of labeling tests, provides much better
   support for advanced features such as parameterized tests, and does not
   require re-running CMake to discover added or removed tests within a test
-  executable.
+  executable.  Note that a breaking change was made in CMake 3.10.3 to address
+  an ambiguity of the ``TIMEOUT`` keyword (see :ref:`Release Notes 3.10.3`).
 
 * The :module:`InstallRequiredSystemLibraries` module gained support
   for installing Intel compiler runtimes.
@@ -267,3 +268,17 @@ Changes made since CMake 3.10.0 include the following.
 * The :manual:`cmake-server(7)` ``codemodel`` response ``crossReferences``
   field added by 3.10.0 has been dropped due to excessive memory usage.
   Another approach will be needed to provide backtrace information.
+
+.. _`Release Notes 3.10.3`:
+
+3.10.3
+------
+
+* CMake 3.10.1 added a ``TIMEOUT`` option to :command:`gtest_discover_tests`
+  from the :module:`GoogleTest` module.  That keyword clashed with the
+  ``TIMEOUT`` test property, which is one of the common properties that
+  would be set with the command's ``PROPERTIES`` keyword, usually leading
+  to legal but unintended behavior.  The keyword was changed to
+  ``DISCOVERY_TIMEOUT`` in CMake 3.10.3 to address this problem.  The
+  ambiguous behavior of the :command:`gtest_discover_tests` command's
+  ``TIMEOUT`` keyword in 3.10.1 and 3.10.2 has not been preserved.

Modules/GoogleTest.cmake

@@ -150,6 +150,7 @@ same as the Google Test name (i.e. ``suite.testcase``); see also
                          [NO_PRETTY_TYPES] [NO_PRETTY_VALUES]
                          [PROPERTIES name1 value1...]
                          [TEST_LIST var]
+                         [DISCOVERY_TIMEOUT seconds]
     )
 
   ``gtest_discover_tests`` sets up a post-build command on the test executable
@@ -217,7 +218,7 @@ same as the Google Test name (i.e. ``suite.testcase``); see also
     executable is being used in multiple calls to ``gtest_discover_tests()``.
     Note that this variable is only available in CTest.
 
-  ``TIMEOUT num``
+  ``DISCOVERY_TIMEOUT num``
     Specifies how long (in seconds) CMake will wait for the test to enumerate
     available tests.  If the test takes longer than this, discovery (and your
     build) will fail.  Most test executables will enumerate their tests very
@@ -225,6 +226,16 @@ same as the Google Test name (i.e. ``suite.testcase``); see also
     longer timeout.  The default is 5.  See also the ``TIMEOUT`` option of
     :command:`execute_process`.
 
+    .. note::
+
+      In CMake versions 3.10.1 and 3.10.2, this option was called ``TIMEOUT``.
+      This clashed with the ``TIMEOUT`` test property, which is one of the
+      common properties that would be set with the ``PROPERTIES`` keyword,
+      usually leading to legal but unintended behavior.  The keyword was
+      changed to ``DISCOVERY_TIMEOUT`` in CMake 3.10.3 to address this
+      problem.  The ambiguous behavior of the ``TIMEOUT`` keyword in 3.10.1
+      and 3.10.2 has not been preserved.
+
 #]=======================================================================]
 
 #------------------------------------------------------------------------------
@@ -357,7 +368,7 @@ function(gtest_discover_tests TARGET)
   cmake_parse_arguments(
     ""
     "NO_PRETTY_TYPES;NO_PRETTY_VALUES"
-    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST;TIMEOUT"
+    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST;DISCOVERY_TIMEOUT"
     "EXTRA_ARGS;PROPERTIES"
     ${ARGN}
   )
@@ -368,8 +379,8 @@ function(gtest_discover_tests TARGET)
   if(NOT _TEST_LIST)
     set(_TEST_LIST ${TARGET}_TESTS)
   endif()
-  if(NOT _TIMEOUT)
-    set(_TIMEOUT 5)
+  if(NOT _DISCOVERY_TIMEOUT)
+    set(_DISCOVERY_TIMEOUT 5)
   endif()
 
   get_property(
@@ -418,7 +429,7 @@ function(gtest_discover_tests TARGET)
             -D "NO_PRETTY_VALUES=${_NO_PRETTY_VALUES}"
             -D "TEST_LIST=${_TEST_LIST}"
             -D "CTEST_FILE=${ctest_tests_file}"
-            -D "TEST_DISCOVERY_TIMEOUT=${_TIMEOUT}"
+            -D "TEST_DISCOVERY_TIMEOUT=${_DISCOVERY_TIMEOUT}"
             -P "${_GOOGLETEST_DISCOVER_TESTS_SCRIPT}"
     VERBATIM
   )

Tests/RunCMake/GoogleTest/GoogleTest-discovery-timeout-stdout.txt

@@ -1,7 +1,7 @@
 ( *|[0-9]+>)CMake Error at .*GoogleTestAddTests.cmake:[0-9]+ \(message\):
 ( *|[0-9]+>)  Error running test executable.
 ?( *|[0-9]+>)
-( *|[0-9]+>)    Path: '.*timeout_test(\.exe)?'
+( *|[0-9]+>)    Path: '.*discovery_timeout_test(\.exe)?'
 ( *|[0-9]+>)    Result: Process terminated due to timeout
 ( *|[0-9]+>)    Output:
 ( *|[0-9]+>)     +

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout1-result.txt

@@ -0,0 +1 @@
+[^0]

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout1-stderr.txt

@@ -0,0 +1 @@
+Errors while running CTest

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout1-stdout.txt

@@ -0,0 +1,10 @@
+Test project .*GoogleTest-build
+[ \t]*Start [0-9]+: property_timeout.case_no_discovery
+[^\n]+property_timeout.case_no_discovery +\.+\*\*\*Timeout +[0-9.]+ sec
++
+0% tests passed, 1 tests failed out of 1
++
+Total Test time \(real\) = +[0-9.]+ sec
++
+The following tests FAILED:
+[^\n]*property_timeout.case_no_discovery \(Timeout\)

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout2-result.txt

@@ -0,0 +1 @@
+[^0]

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout2-stderr.txt

@@ -0,0 +1 @@
+Errors while running CTest

Tests/RunCMake/GoogleTest/GoogleTest-property-timeout2-stdout.txt

@@ -0,0 +1,10 @@
+Test project .*GoogleTest-build
+[ \t]*Start [0-9]+: property_timeout.case_with_discovery
+[^\n]+property_timeout.case_with_discovery +\.+\*\*\*Timeout +[0-9.]+ sec
++
+0% tests passed, 1 tests failed out of 1
++
+Total Test time \(real\) = +[0-9.]+ sec
++
+The following tests FAILED:
+[^\n]*property_timeout.case_with_discovery \(Timeout\)

Tests/RunCMake/GoogleTest/GoogleTest-test-missing-stderr.txt

@@ -1,2 +1,2 @@
-Unable to find executable: timeout_test_NOT_BUILT
+Unable to find executable: no_tests_defined_NOT_BUILT
 Errors while running CTest

Tests/RunCMake/GoogleTest/GoogleTest.cmake

@@ -22,8 +22,38 @@ gtest_discover_tests(
   PROPERTIES LABELS TEST2
 )
 
-add_executable(timeout_test timeout_test.cpp)
+add_executable(no_tests_defined no_tests_defined.cpp)
 
 gtest_discover_tests(
-  timeout_test
+  no_tests_defined
+)
+
+# Note change in behavior of TIMEOUT keyword in 3.10.3
+# where it was renamed to DISCOVERY_TIMEOUT to prevent it
+# from shadowing the TIMEOUT test property. Verify the
+# 3.10.3 and later behavior, old behavior added in 3.10.1
+# is not supported.
+add_executable(property_timeout_test timeout_test.cpp)
+target_compile_definitions(property_timeout_test PRIVATE sleepSec=10)
+
+gtest_discover_tests(
+  property_timeout_test
+  TEST_PREFIX property_
+  TEST_SUFFIX _no_discovery
+  PROPERTIES TIMEOUT 2
+)
+gtest_discover_tests(
+  property_timeout_test
+  TEST_PREFIX property_
+  TEST_SUFFIX _with_discovery
+  DISCOVERY_TIMEOUT 20
+  PROPERTIES TIMEOUT 2
+)
+
+add_executable(discovery_timeout_test timeout_test.cpp)
+target_compile_definitions(discovery_timeout_test PRIVATE discoverySleepSec=10)
+gtest_discover_tests(
+  discovery_timeout_test
+  TEST_PREFIX discovery_
+  DISCOVERY_TIMEOUT 2
 )

Tests/RunCMake/GoogleTest/RunCMakeTest.cmake

@@ -19,12 +19,19 @@ function(run_GoogleTest)
     --target fake_gtest
   )
 
-  set(RunCMake_TEST_OUTPUT_MERGE 1)
-  run_cmake_command(GoogleTest-timeout
+  run_cmake_command(GoogleTest-property-timeout-exe
     ${CMAKE_COMMAND}
     --build .
     --config Debug
-    --target timeout_test
+    --target property_timeout_test
+  )
+
+  set(RunCMake_TEST_OUTPUT_MERGE 1)
+  run_cmake_command(GoogleTest-discovery-timeout
+    ${CMAKE_COMMAND}
+    --build .
+    --config Debug
+    --target discovery_timeout_test
   )
   set(RunCMake_TEST_OUTPUT_MERGE 0)
 
@@ -45,7 +52,21 @@ function(run_GoogleTest)
   run_cmake_command(GoogleTest-test-missing
     ${CMAKE_CTEST_COMMAND}
     -C Debug
-    -R timeout
+    -R no_tests_defined
+    --no-label-summary
+  )
+
+  run_cmake_command(GoogleTest-property-timeout1
+    ${CMAKE_CTEST_COMMAND}
+    -C Debug
+    -R property_timeout\\.case_no_discovery
+    --no-label-summary
+  )
+
+  run_cmake_command(GoogleTest-property-timeout2
+    ${CMAKE_CTEST_COMMAND}
+    -C Debug
+    -R property_timeout\\.case_with_discovery
     --no-label-summary
   )
 endfunction()

Tests/RunCMake/GoogleTest/no_tests_defined.cpp

@@ -0,0 +1,4 @@
+int main()
+{
+  return 0;
+}

Tests/RunCMake/GoogleTest/timeout_test.cpp

@@ -4,12 +4,36 @@
 #include <unistd.h>
 #endif
 
-int main()
+#include <iostream>
+#include <string>
+
+void sleepFor(unsigned seconds)
 {
 #if defined(_WIN32)
-  Sleep(10000);
+  Sleep(seconds * 1000);
 #else
-  sleep(10);
+  sleep(seconds);
 #endif
+}
+
+int main(int argc, char** argv)
+{
+  // Note: GoogleTest.cmake doesn't actually depend on Google Test as such;
+  // it only requires that we produce output in the expected format when
+  // invoked with --gtest_list_tests. Thus, we fake that here. This allows us
+  // to test the module without actually needing Google Test.
+  if (argc > 1 && std::string(argv[1]) == "--gtest_list_tests") {
+    std::cout << "timeout." << std::endl;
+    std::cout << "  case" << std::endl;
+#ifdef discoverySleepSec
+    sleepFor(discoverySleepSec);
+#endif
+    return 0;
+  }
+
+#ifdef sleepSec
+  sleepFor(sleepSec);
+#endif
+
   return 0;
 }