fix coverage and integrate into codecov.io

.codecov.yml

@@ -22,13 +22,7 @@ ignore:
   - "build/_deps/**/*"
   - "test/**/*"
 
-# Strip the GitHub Actions container-mount prefix (/__w/<owner>/<repo>/)
-# from paths emitted by gcovr --root "$GITHUB_WORKSPACE".
-# Without this, Codecov cannot match coverage lines to repo files.
-fixes:
-  - "/__w/git-wip/git-wip/::"
-
 comment:
   layout: "reach,diff,flags,files,footer"
   behavior: default
-  require_changes: no
+  require_changes: no

.github/workflows/ci.yml

@@ -192,7 +192,7 @@ jobs:
           retention-days: 7
 
   coverage:
-    name: Coverage (debian:stable / clang / Debug)
+    name: Coverage (debian:stable / gcc / Debug)
 
     runs-on: ubuntu-latest
 
@@ -206,7 +206,7 @@ jobs:
       - name: Install dependencies
         env:
           DEBIAN_FRONTEND: noninteractive
-        run: bash dependencies.sh --compiler=clang
+        run: bash dependencies.sh --compiler=gcc --coverage
 
       - name: Cache CMake FetchContent (spdlog, clipp, fmt)
         uses: actions/cache@v5
@@ -222,39 +222,19 @@ jobs:
           git config --global user.name  "GitHub Actions"
           git config --global init.defaultBranch master
 
-      - name: Build with coverage
+      - name: Build, test, and collect coverage
         env:
-          CC:  clang
-          CXX: clang++
+          CC:  gcc
+          CXX: g++
           CI:  "1"
-          COVERAGE: "1"
-        run: make TYPE=Debug test
-
-      - name: Collect coverage data
-        run: |
-          gcovr --cobertura coverage.xml \
-            --gcov-executable 'llvm-cov gcov' \
-            --gcov-ignore-errors=no_working_dir_found \
-            --exclude 'build/_deps/' \
-            --exclude 'test/' \
-            --root "$GITHUB_WORKSPACE"
-
-      - name: Verify coverage file
-        run: |
-          ls -la coverage.xml
-          head -50 coverage.xml
-
-      - name: Install codecov dependencies
-        env:
-          DEBIAN_FRONTEND: noninteractive
-        run: apt-get update && apt-get install -y curl gpg
+        run: make CC=gcc CXX=g++ TYPE=Debug coverage REBUILD=1
 
       - name: Upload to Codecov
         uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          files: ./coverage.xml
+          files: ./coverage.info
           flags: unittests
-          name: debian-stable-clang-debug
+          name: debian-stable-gcc-debug
           verbose: true
           fail_ci_if_error: true

.gitignore

@@ -6,6 +6,7 @@ build/
 
 coverage-report/
 coverage.xml
+coverage.info
 
 ### C++
 # Prerequisites

CMakeLists.txt

@@ -8,12 +8,7 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 # Enable generation of compile_commands.json
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-# Code coverage options
 option(WIP_COVERAGE "Enable code coverage instrumentation" OFF)
-if(WIP_COVERAGE)
-    add_compile_options(-fprofile-arcs -ftest-coverage)
-    add_link_options(-fprofile-arcs -ftest-coverage)
-endif()
 
 include(FetchContent)
 include(CheckCXXSourceCompiles)
@@ -26,6 +21,15 @@ FetchContent_Declare(
 
 FetchContent_MakeAvailable(spdlog)
 
+# Code coverage options — applied AFTER FetchContent so that third-party
+# dependencies (spdlog, fmt, …) are NOT instrumented.  Mixing gcov versions
+# between the host compiler and a pre-built dep causes "version mismatch"
+# errors at runtime that pollute test output.
+if(WIP_COVERAGE)
+    add_compile_options(-fprofile-arcs -ftest-coverage)
+    add_link_options(-fprofile-arcs -ftest-coverage)
+endif()
+
 # Detect whether the compiler's standard library ships <print> (C++23 P2093).
 # GCC < 14 and some older clangs lack it even with -std=c++23.
 check_cxx_source_compiles("

Makefile

@@ -32,6 +32,12 @@ NPROC ?= $(shell nproc || echo 1)
 CC ?= $(shell which clang gcc cc | head -n1)
 CXX ?= $(shell which clang g++ c++ | head -n1)
 COVERAGE ?= false
+# Locate the right gcov-compatible tool to match the compiler:
+# - if CC is clang, use llvm-cov (prefer plain symlink, fall back to versioned)
+# - otherwise use plain gcov
+# Use = (recursive) not := (immediate) so CC override on the command line is respected.
+_IS_CLANG = $(shell $(CC) --version 2>/dev/null | grep -c clang)
+GCOV_TOOL = $(if $(filter 1,$(_IS_CLANG)),$(shell which llvm-cov 2>/dev/null || ls /usr/bin/llvm-cov-* 2>/dev/null | sort -V | tail -1) gcov,gcov)
 $(info ## TYPE=${TYPE} CC=${CC} CXX=${CXX} COVERAGE=${COVERAGE})
 
 # Coverage flag for CMake
@@ -61,13 +67,34 @@ test: ## run unit tests (with ctest, uses REBUILD={true,false}, COVERAGE={true,f
 	${Q}cd "${BUILD}"/ && ctest -C "${TYPE}" $(if ${CI},--output-on-failure -VV)
 	${Q}echo " ✅ Unit tests complete."
 
-coverage: ## check code coverage (with gcovr, uses REBUILD={true,false})
+coverage: ## check code coverage (with lcov, uses REBUILD={true,false})
 	${Q}$(if $(filter 1 yes true YES TRUE,${REBUILD}),rm -rf "${BUILD}"/)
-	${Q}${CMAKE} -G ${GENERATOR} -S. -B${BUILD} -DCMAKE_INSTALL_PREFIX="$(PREFIX)" -DCMAKE_BUILD_TYPE="${TYPE}" -DWIP_COVERAGE=ON
+	${Q}${CMAKE} -G ${GENERATOR} -S. -B${BUILD} -DCMAKE_INSTALL_PREFIX="$(PREFIX)" -DCMAKE_BUILD_TYPE="${TYPE}" -DWIP_COVERAGE=ON -DCMAKE_C_COMPILER="${CC}" -DCMAKE_CXX_COMPILER="${CXX}"
 	${Q}${CMAKE} --build "${BUILD}" --config "${TYPE}" --parallel "${NPROC}"
-	${Q}cd "${BUILD}"/ && ctest -C "${TYPE}" -VV
+	${Q}cd "${BUILD}"/ && ctest -C "${TYPE}" $(if ${CI},--output-on-failure -VV)
+	${Q}printf '#!/bin/sh\nexec $(GCOV_TOOL) "$$@"\n' > "${BUILD}/gcov-tool.sh" && chmod +x "${BUILD}/gcov-tool.sh"
+	${Q}lcov --capture --directory "${BUILD}/src" \
+		             --directory "${BUILD}/test" \
+		--gcov-tool "${BUILD}/gcov-tool.sh" \
+		--ignore-errors inconsistent \
+		--ignore-errors inconsistent \
+		--ignore-errors format \
+		--ignore-errors unsupported \
+		--output-file coverage.info
+	${Q}lcov --remove coverage.info '/usr/*' '*/test/*' \
+		--ignore-errors inconsistent \
+		--ignore-errors inconsistent \
+		--ignore-errors format \
+		--ignore-errors unsupported \
+		--ignore-errors corrupt \
+		--output-file coverage.info
 	${Q}mkdir -p coverage-report
-	${Q}gcovr --html coverage-report/index.html --root . "${BUILD}"
+	${Q}genhtml coverage.info --output-directory coverage-report \
+		--ignore-errors inconsistent \
+		--ignore-errors inconsistent \
+		--ignore-errors corrupt \
+		--ignore-errors unsupported \
+		--ignore-errors category
 	${Q}echo " ✅ Coverage report generated in coverage-report/"
 
 install: ## install the package (to the `PREFIX`, uses REBUILD={true,false})

dependencies.sh

@@ -113,6 +113,7 @@ function want_one_of() {
 # ---------------------------------------------------------------------------
 
 compiler=""   # empty → auto-select via must_have_one_of
+coverage=0    # --coverage → install lcov, curl, gpg
 
 for arg in "$@" ; do
     case "$arg" in
@@ -122,9 +123,11 @@ for arg in "$@" ; do
         --compiler=clang) compiler=clang ;;
         --compiler=*)
             die "unknown --compiler value '${arg#--compiler=}' (expected gcc or clang)" ;;
+        --coverage)
+            coverage=1 ;;
         -h|--help)
             cat <<'EOF'
-Usage: dependencies.sh [--compiler=<gcc|clang>] [-h|--help]
+Usage: dependencies.sh [--compiler=<gcc|clang>] [--coverage] [-h|--help]
 
 Install build dependencies for git-wip.
 
@@ -133,6 +136,8 @@ Options:
   --compiler=clang  Install clang
   (no flag)         Install whichever of clang/gcc is available (auto-select)
 
+  --coverage        Also install coverage tools (lcov, curl, gpg)
+
   -h, --help        Show this help and exit
 EOF
             exit 0
@@ -205,22 +210,19 @@ case "$pkg_mgr" in
             libgmock-dev
             libgtest-dev
             libgit2-dev
-            gcovr
         )
         ;;
     dnf)
         packages+=(
             gtest-devel
             gmock-devel
             libgit2-devel
-            gcovr
         )
         ;;
     pacman)
         # Arch uses different package names
         packages+=(
             libgit2
-            gcovr
         )
         # Replace base packages with Arch equivalents
         packages=( "${packages[@]/ninja-build/ninja}" )
@@ -233,6 +235,21 @@ case "$pkg_mgr" in
         ;;
 esac
 
+# Coverage tools (only when --coverage is requested)
+if [ "$coverage" = 1 ]; then
+    case "$pkg_mgr" in
+        apt)
+            packages+=( lcov curl gpg )
+            ;;
+        dnf)
+            packages+=( lcov curl gnupg2 )
+            ;;
+        pacman)
+            packages+=( lcov curl gnupg )
+            ;;
+    esac
+fi
+
 set -e -x
 
 case "$pkg_mgr" in