Simplify code coverage builds (PyVRP#557)

* Simplify code coverage builds

* Try clang, using Meson's coverage-xml target

* Add gcovr configuration

* Exclude throw branches

Author: N-Wouda

.github/workflows/CI.yml

@@ -89,16 +89,16 @@ jobs:
         run: |
           poetry install --only-root
           poetry run python build_extensions.py --build_type debug --clean
-      - name: Run tests
-        run: poetry run pytest
-      - if: matrix.compiler == 'gcc'
-        # Clang does not generate accurate coverage reports, so there is no
-        # point in uploading those.
-        uses: codecov/codecov-action@v4
+      - name: Run tests and generate coverage reports
+        run: |
+          poetry run pytest
+          poetry run ninja coverage-xml -C build
+      - uses: codecov/codecov-action@v4
         with:
           fail_ci_if_error: true
           token: ${{ secrets.CODECOV_TOKEN }}
-          plugins: gcov, pycoverage
+          plugins: pycoverage
+          files: build/meson-logs/coverage.xml
       - if: matrix.compiler == 'gcc'
         name: Install Valgrind
         run: sudo apt install valgrind

build_extensions.py

@@ -93,6 +93,7 @@ def configure(
         f"-Dpython.platlibdir={cwd.absolute()}",
         f"-Dproblem={problem}",
         f"-Dstrip={'true' if build_type == 'release' else 'false'}",
+        f"-Db_coverage={'true' if build_type != 'release' else 'false'}",
         *additional,
         # fmt: on
     ]

gcovr.cfg

@@ -0,0 +1,3 @@
+exclude-unreachable-branches = yes
+exclude-throw-branches = yes
+filter = pyvrp/

meson.build

@@ -11,19 +11,6 @@ project(
     ]
 )
 
-if get_option('buildtype') == 'debug'
-    compiler = meson.get_compiler('cpp')
-
-    if compiler.has_argument('-fprofile-abs-path')
-        # clang does not have this particular flag, so we only add it when
-        # compiling with gcc. It's helpful in determining code coverage.
-        add_project_arguments('-fprofile-abs-path', language: 'cpp')
-    endif
-
-    add_project_arguments('--coverage', language: 'cpp')
-    add_project_link_arguments('--coverage', language: 'cpp')
-endif
-
 if get_option('problem') == 'cvrp'
     # CVRP does not have time windows, so we set a flag that compiles time 
     # window stuff out of the extension modules.

pyproject.toml

@@ -88,9 +88,11 @@ pytest-cov = ">=2.6.1"
 codecov = "*"
 
 # These are used in the build script: for compiling the library (meson, ninja)
-# and for generating doc or type stubs (docblock, mypy).
+# and for generating docs (docblock), type stubs (mypy), and coverage reports
+# (gcovr).
 meson = "^1.0.0"
 ninja = "^1.11.1"
+gcovr = "^7.2"
 mypy = "^0.991"
 docblock = "^0.1.5"
 

pyvrp/cpp/search/SwapTails.cpp

@@ -20,10 +20,10 @@ pyvrp::Cost SwapTails::evaluate(Route::Node *U,
 
     // We're going to incur fixed cost if a route is currently empty but
     // becomes non-empty due to the proposed move.
-    if (uRoute->empty() && U->isDepot() && !n(V)->isDepot())
+    if (uRoute->empty() && !n(V)->isDepot())
         deltaCost += uRoute->fixedVehicleCost();
 
-    if (vRoute->empty() && V->isDepot() && !n(U)->isDepot())
+    if (vRoute->empty() && !n(U)->isDepot())
         deltaCost += vRoute->fixedVehicleCost();
 
     // We lose fixed cost if a route becomes empty due to the proposed move.