Caching clang-tidy results

cmake/clang_tidy.cmake

@@ -3,10 +3,20 @@ option (ENABLE_CLANG_TIDY "Use clang-tidy static analyzer" OFF)
 
 if (ENABLE_CLANG_TIDY)
 
-    find_program (CLANG_TIDY_PATH NAMES "clang-tidy" "clang-tidy-15" "clang-tidy-14" "clang-tidy-13" "clang-tidy-12")
+    find_program (CLANG_TIDY_CACHE_PATH NAMES "clang-tidy-cache")
+    if (CLANG_TIDY_CACHE_PATH)
+        find_program (_CLANG_TIDY_PATH NAMES "clang-tidy" "clang-tidy-15" "clang-tidy-14" "clang-tidy-13" "clang-tidy-12")
+
+        # Why do we use ';' here?
+        # It's a cmake black magic: https://cmake.org/cmake/help/latest/prop_tgt/LANG_CLANG_TIDY.html#prop_tgt:%3CLANG%3E_CLANG_TIDY
+        # The CLANG_TIDY_PATH is passed to CMAKE_CXX_CLANG_TIDY, which follows CXX_CLANG_TIDY syntax.
+        set (CLANG_TIDY_PATH "${CLANG_TIDY_CACHE_PATH};${_CLANG_TIDY_PATH}" CACHE STRING "A combined command to run clang-tidy with caching wrapper")
+    else ()
+        find_program (CLANG_TIDY_PATH NAMES "clang-tidy" "clang-tidy-15" "clang-tidy-14" "clang-tidy-13" "clang-tidy-12")
+    endif ()
 
     if (CLANG_TIDY_PATH)
-        message(STATUS
+        message (STATUS
             "Using clang-tidy: ${CLANG_TIDY_PATH}.
             The checks will be run during build process.
             See the .clang-tidy file at the root directory to configure the checks.")
@@ -15,11 +25,15 @@ if (ENABLE_CLANG_TIDY)
 
         # clang-tidy requires assertions to guide the analysis
         # Note that NDEBUG is set implicitly by CMake for non-debug builds
-        set(COMPILER_FLAGS "${COMPILER_FLAGS} -UNDEBUG")
+        set (COMPILER_FLAGS "${COMPILER_FLAGS} -UNDEBUG")
 
-        # The variable CMAKE_CXX_CLANG_TIDY will be set inside src and base directories with non third-party code.
+        # The variable CMAKE_CXX_CLANG_TIDY will be set inside the following directories with non third-party code.
+        # - base
+        # - programs
+        # - src
+        # - utils
         # set (CMAKE_CXX_CLANG_TIDY "${CLANG_TIDY_PATH}")
     else ()
-        message(${RECONFIGURE_MESSAGE_LEVEL} "clang-tidy is not found")
+        message (${RECONFIGURE_MESSAGE_LEVEL} "clang-tidy is not found")
     endif ()
 endif ()

docker/packager/binary/Dockerfile

@@ -91,6 +91,9 @@ ENV PATH="$PATH:/usr/local/go/bin"
 ENV GOPATH=/workdir/go
 ENV GOCACHE=/workdir/
 
+RUN curl https://raw.githubusercontent.com/matus-chochlik/ctcache/7fd516e91c17779cbc6fc18bd119313d9532dd90/clang-tidy-cache -Lo /usr/bin/clang-tidy-cache \
+  && chmod +x /usr/bin/clang-tidy-cache
+
 RUN mkdir /workdir && chmod 777 /workdir
 WORKDIR /workdir
 

docker/packager/packager

@@ -258,6 +258,10 @@ def parse_env_variables(
         if clang_tidy:
             # 15G is not enough for tidy build
             cache_maxsize = "25G"
+
+            # `CTCACHE_DIR` has the same purpose as the `CCACHE_DIR` above.
+            # It's there to have the clang-tidy cache embedded into our standard `CCACHE_DIR`
+            result.append("CTCACHE_DIR=/ccache/clang-tidy-cache")
         result.append(f"CCACHE_MAXSIZE={cache_maxsize}")
 
     if distcc_hosts:
@@ -282,9 +286,7 @@ def parse_env_variables(
         cmake_flags.append("-DENABLE_TESTS=1")
 
     if shared_libraries:
-        cmake_flags.append(
-            "-DUSE_STATIC_LIBRARIES=0 -DSPLIT_SHARED_LIBRARIES=1"
-        )
+        cmake_flags.append("-DUSE_STATIC_LIBRARIES=0 -DSPLIT_SHARED_LIBRARIES=1")
         # We can't always build utils because it requires too much space, but
         # we have to build them at least in some way in CI. The shared library
         # build is probably the least heavy disk-wise.