After upgrading to ccache-4.0-1.fc33, I can't build WebKit anymore. Looking at my CMakeError.log, all of CMake's feature checks are failing like so: Source file was: int main() { return 0; } Performing C++ SOURCE FILE Test CXX_COMPILER_SUPPORTS_-Wno-suggest-attribute=format failed with the following output: Change Dir: /home/mcatanzaro/Projects/WebKit/WebKitBuild/GNOME/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/ninja-build cmTC_79f61 && [1/2] Building CXX object CMakeFiles/cmTC_79f61.dir/src.cxx.o <command-line>: warning: ISO C++11 requires whitespace after the macro name [2/2] Linking CXX executable cmTC_79f61 FAILED: cmTC_79f61 : && /usr/lib64/ccache/c++ -fcolor-diagnostics -Wextra -Wall -Wno-expansion-to-defined -Wno-noexcept-type -Wno-psabi -Wno-misleading-indentation -Wno-maybe-uninitialized -Wwrite-strings -Wundef -Wpointer-arith -Wmissing-format-attribute -Wformat-security -Wcast-align -Wno-tautological-compare -g -O0 -fno-strict-aliasing -fno-exceptions -fno-rtti -DCXX_COMPILER_SUPPORTS_-Wno-suggest-attribute=format -L/home/mcatanzaro/Projects/GNOME/install/lib -fuse-ld=gold -Wl,--disable-new-dtags CMakeFiles/cmTC_79f61.dir/src.cxx.o -o cmTC_79f61 && : c++: error: unrecognized command-line option '-fcolor-diagnostics' ninja: build stopped: subcommand failed. The problem is every check fails because CMake passes -fcolor-diagnostics, which is a clang flag. It is guaranteed to fail when passed to GCC. Why is CMake doing this? Looking at my build log, that happens because CMake's check_c_compiler_flag() and check_cxx_compiler_flag() succeed when passed -fcolor-diagonstics. They also fail when -fdiagnostics-color=always is passed. That is telling, because that is a GCC flag that would only fail if passed to clang. So somehow ccache has gone crazy and decided to use clang instead of GCC when performing some cmake feature tests, then switch back to GCC to perform others. That's wild and I haven't figured out why yet, but downgrading ccache fixes the issue. Something really weird is going on with ccache 4.0.
OK the problem is: https://github.com/ccache/ccache/issues/740. It is already fixed by upstream in ccache 4.2, which is now available. (I see there was an initial attempt to fix this in ccache 4.1, but the fix was insufficient). Only projects that perform feature tests to check for -fcolor-diagnostics or -fdiagnostics-color would be broken.
FEDORA-2021-7d5a49984e has been submitted as an update to Fedora 33. https://bodhi.fedoraproject.org/updates/FEDORA-2021-7d5a49984e
Thanks for the quick response!
FEDORA-2021-7d5a49984e has been pushed to the Fedora 33 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --advisory=FEDORA-2021-7d5a49984e` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2021-7d5a49984e See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2021-7d5a49984e has been pushed to the Fedora 33 stable repository. If problem still persists, please make note of it in this bug report.
Reopening this. It was fixed in ccache-4.2-1.fc33, and stayed fixed in F34, but the bug is back again in ccache-4.2.1-2.fc35: [32/5586] Building CXX object Source/bmalloc/CMakeFiles/bmalloc.dir/bmalloc/Deallocator.cpp.o FAILED: Source/bmalloc/CMakeFiles/bmalloc.dir/bmalloc/Deallocator.cpp.o /usr/lib64/ccache/c++ -DBUILDING_GTK__=1 -DBUILDING_WITH_CMAKE=1 -DBUILDING_bmalloc -DBWRAP_EXECUTABLE=\"/usr/bin/bwrap\" -DDBUS_PROXY_EXECUTABLE=\"/usr/bin/xdg-dbus-proxy\" -DGETTEXT_PACKAGE=\"WebKit2GTK-4.1\" -DHAVE_CONFIG_H=1 -DJSC_GLIB_API_ENABLED -DWEBKITGTK_API_VERSION_STRING=\"4.1\" -I/home/mcatanzaro/Projects/WebKit/Source/bmalloc -fcolor-diagnostics -Wextra -Wall -Wno-expansion-to-defined -Wno-nonnull -Wno-array-bounds -Wno-noexcept-type -Wno-psabi -Wno-misleading-indentation -Wno-maybe-uninitialized -Wwrite-strings -Wundef -Wpointer-arith -Wmissing-format-attribute -Wformat-security -Wcast-align -Wno-tautological-compare -g -O0 -fno-strict-aliasing -fno-exceptions -fno-rtti -O2 -g -DNDEBUG -fPIC -fvisibility=hidden -std=c++17 -MD -MT Source/bmalloc/CMakeFiles/bmalloc.dir/bmalloc/Deallocator.cpp.o -MF Source/bmalloc/CMakeFiles/bmalloc.dir/bmalloc/Deallocator.cpp.o.d -o Source/bmalloc/CMakeFiles/bmalloc.dir/bmalloc/Deallocator.cpp.o -c /home/mcatanzaro/Projects/WebKit/Source/bmalloc/bmalloc/Deallocator.cpp c++: error: unrecognized command-line option ‘-fcolor-diagnostics’ That is ccache trying to pass the clang-specific -fcolor-diagnostics flag to GCC. As a workaround, I have uninstalled ccache. My guess is that 4.2 is good and 4.2.1 is bad. Looking at suspicious commits between those ranges, I found this one: https://github.com/ccache/ccache/commit/97a40af49f56e4be2db5e4318d8131e937bd5598#diff-d294680506e79f67b7538b1eb162b58cf8f0c1a66f06d52db43179d69a995a42
Er, can't reproduce today after deleting ~/.ccache. My guess is that it is failing to handle upgrades gracefully. Probably not worth keeping this bug open if the fix is that simple.
I would file upstream if this remains a persistent issue.