Add C++20 testing, remove C++14 testing.

Secondary changes:

* pybind11 needs to be pinned to a version right before pybind/pybind11#4786 was merged, to avoid `ctest` `permission denied` errors (to be debugged separately).

* `find_package(PythonLibs REQUIRED)` is removed. It is deprecated (https://github.com/pybind/pybind11/blob/master/docs/faq.rst) and evidently not needed.

* More complete logging.

PiperOrigin-RevId: 595435856

Author: rwgk

CMakeLists.txt

@@ -12,8 +12,6 @@ set(BUILD_TESTING OFF)
 set(CMAKE_POSITION_INDEPENDENT_CODE TRUE)
 set(CMAKE_INTERPROCEDURAL_OPTIMIZATION FALSE)
 
-find_package(PythonLibs REQUIRED)
-
 FetchContent_Declare(
   abseil-cpp
   URL https://github.com/abseil/abseil-cpp/archive/refs/tags/20230802.0.tar.gz
@@ -22,7 +20,7 @@ FetchContent_Declare(
 
 FetchContent_Declare(
   pybind11
-  URL https://github.com/pybind/pybind11/archive/refs/heads/master.tar.gz)
+  URL https://github.com/pybind/pybind11/archive/7d538a42750c8580eeaac10e505840a3694b04c8.tar.gz)
 
 FetchContent_MakeAvailable(abseil-cpp pybind11)
 

scripts/build_and_run_tests_bazel.sh

@@ -6,7 +6,7 @@
 # - builds and runs tests
 
 set -e  # exit when any command fails
-# set -x  # Prints all executed command
+set -x  # Prints all executed commands
 
 MYDIR="$(dirname "$(realpath "$0")")"
 
@@ -80,5 +80,5 @@ export PYTHON_LIB_PATH=`python3 -c "import sysconfig; print(sysconfig.get_path('
 echo "Using PYTHON_BIN_PATH: $PYTHON_BIN_PATH"
 echo "Using PYTHON_LIB_PATH: $PYTHON_LIB_PATH"
 
-BAZEL_CXXOPTS="-std=c++14" bazel test ... --test_output=errors "$@"
 BAZEL_CXXOPTS="-std=c++17" bazel test ... --test_output=errors "$@"
+BAZEL_CXXOPTS="-std=c++20" bazel test ... --test_output=errors "$@"

scripts/build_and_run_tests_cmake.sh

@@ -6,7 +6,7 @@
 # - builds and runs tests
 
 set -e  # exit when any command fails
-# set -x  # Prints all executed command
+set -x  # Prints all executed commands
 
 MYDIR="$(dirname "$(realpath "$0")")"
 
@@ -87,17 +87,17 @@ fi
 mkdir tmp_build
 cd tmp_build
 
-# C++14
-cmake ../ -DCMAKE_CXX_STANDARD=14 -DCMAKE_VERBOSE_MAKEFILE=ON
+# C++17
+cmake ../ -DCMAKE_CXX_STANDARD=17 -DCMAKE_VERBOSE_MAKEFILE=ON
 make "$@"
-ctest --output-on-failure
+ctest --output-on-failure --extra-verbose
 
 rm -r ./*
 
-# C++17
-cmake ../ -DCMAKE_CXX_STANDARD=17 -DCMAKE_VERBOSE_MAKEFILE=ON
+# C++20
+cmake ../ -DCMAKE_CXX_STANDARD=20 -DCMAKE_VERBOSE_MAKEFILE=ON
 make "$@"
-ctest --output-on-failure
+ctest --output-on-failure --extra-verbose
 
 cd ../
 rm -r tmp_build