FEAT: enable disabling branch coverage

src/compwa_policy/__init__.py

@@ -34,6 +34,7 @@ class Arguments:
     allow_labels: bool
     allow_vscode_coverage_gutters: bool
     allowed_cell_metadata: str
+    branch_coverage: bool
     ci_skipped_tests: str
     dev_python_version: PythonVersion
     doc_apt_packages: str

src/compwa_policy/cli/_checks.py

@@ -191,7 +191,12 @@ def run_checks(  # noqa: C901, PLR0912, PLR0915
         do(mypy.main, "mypy" in args.type_checker, precommit_config)
         do(pyright.main, "pyright" in args.type_checker, precommit_config)
         do(ty.main, args.type_checker, args.keep_local_precommit, precommit_config)
-        do(pytest.main, args.allow_vscode_coverage_gutters, args.pytest_single_threaded)
+        do(
+            pytest.main,
+            args.allow_vscode_coverage_gutters,
+            args.pytest_single_threaded,
+            args.branch_coverage,
+        )
         do(pyupgrade.main, precommit_config, args.no_ruff)
         if not args.no_ruff:
             do(ruff.main, precommit_config, ctx.has_notebooks, args.imports_on_top)

src/compwa_policy/cli/_options.py

@@ -112,6 +112,13 @@ class TypeChecker(str, Enum):
     bool | None,
     typer.Option("--imports-on-top", help="Sort notebook imports on the top."),
 ]
+BranchCoverage = Annotated[
+    bool | None,
+    typer.Option(
+        "--branch-coverage/--no-branch-coverage",
+        help="Enable branch coverage in the Coverage.py pytest configuration.",
+    ),
+]
 TypeCheckerOption = Annotated[
     list[TypeChecker] | None,
     typer.Option(

src/compwa_policy/cli/_settings.py

@@ -65,6 +65,7 @@
 _SCOPED_OPTIONS: dict[str, frozenset[str]] = {
     "python": frozenset({
         "allow_vscode_coverage_gutters",
+        "branch_coverage",
         "excluded_python_versions",
         "imports_on_top",
         "keep_local_precommit",
@@ -185,6 +186,7 @@ class Settings(BaseSettings):
     excluded_python_versions: str = ""
     no_ruff: bool = False
     imports_on_top: bool = False
+    branch_coverage: bool = True
     type_checker: list[str] = []
     keep_local_precommit: bool = False
     pytest_single_threaded: bool = False

src/compwa_policy/cli/migrate.py

@@ -54,9 +54,11 @@
 GROUP_FLAGS: dict[str, tuple[str, ...]] = {
     "python": (
         "--allow-vscode-coverage-gutters",
+        "--branch-coverage",
         "--excluded-python-versions",
         "--imports-on-top",
         "--keep-local-precommit",
+        "--no-branch-coverage",
         "--no-ruff",
         "--pytest-single-threaded",
         "--type-checker",
@@ -213,6 +215,11 @@ def _build_policy(args: list[str]) -> dict[str, Any]:
         if flag in {"--python", "--no-python"}:
             policy["python"] = flag == "--python"
             continue
+        if flag in {"--branch-coverage", "--no-branch-coverage"}:
+            sub_table = policy_sub_table("branch_coverage")
+            target = policy if sub_table is None else policy.setdefault(sub_table, {})
+            target["branch-coverage"] = flag == "--branch-coverage"
+            continue
         field = _flag_to_field(flag)
         if field == "environment_variables":
             environment_variables.update(_get_environment_variables(raw_value))

src/compwa_policy/cli/python.py

@@ -5,6 +5,7 @@
 from compwa_policy.cli import _checks
 from compwa_policy.cli._options import (
     AllowVscodeCoverageGutters,
+    BranchCoverage,
     DevPythonVersion,
     ExcludedPythonVersions,
     ImportsOnTop,
@@ -24,6 +25,7 @@ def python(  # noqa: PLR0917
     type_checker: TypeCheckerOption = None,
     no_ruff: NoRuff = None,
     imports_on_top: ImportsOnTop = None,
+    branch_coverage: BranchCoverage = None,
     keep_local_precommit: KeepLocalPrecommit = None,
     pytest_single_threaded: PytestSingleThreaded = None,
     allow_vscode_coverage_gutters: AllowVscodeCoverageGutters = None,
@@ -36,6 +38,7 @@ def python(  # noqa: PLR0917
         type_checker=type_checker,
         no_ruff=no_ruff,
         imports_on_top=imports_on_top,
+        branch_coverage=branch_coverage,
         keep_local_precommit=keep_local_precommit,
         pytest_single_threaded=pytest_single_threaded,
         allow_vscode_coverage_gutters=allow_vscode_coverage_gutters,

src/compwa_policy/python/pytest.py

@@ -25,14 +25,16 @@
     from tomlkit.items import Array
 
 
-def main(coverage_gutters: bool, single_threaded: bool) -> None:
+def main(
+    coverage_gutters: bool, single_threaded: bool, branch_coverage: bool = True
+) -> None:
     with Executor() as do, ModifiablePyproject.load() as pyproject:
         if not has_dependency(pyproject, "pytest"):
             return
         do(_merge_coverage_into_pyproject, pyproject)
         do(_merge_pytest_into_pyproject, pyproject)
         do(_deny_ini_options, pyproject)
-        do(_update_codecov_settings, pyproject)
+        do(_update_codecov_settings, pyproject, branch_coverage)
         do(_update_settings, pyproject)
         do(_update_vscode_settings, pyproject, coverage_gutters, single_threaded)
         if single_threaded:
@@ -131,12 +133,14 @@ def __split_options(arg: str) -> list[str]:
     return options
 
 
-def _update_codecov_settings(pyproject: ModifiablePyproject) -> None:
+def _update_codecov_settings(
+    pyproject: ModifiablePyproject, branch_coverage: bool = True
+) -> None:
     if not has_dependency(pyproject, ("coverage", "pytest-cov")):
         return
     updated = __update_settings(
         config=pyproject.get_table("tool.coverage.run", create=True),
-        branch=True,
+        branch=branch_coverage,
         omit=[
             # https://github.com/microsoft/vscode-python/issues/24973#issuecomment-2886889888
             "benchmarks/**/*.py",

tests/python/test_pytest.py

@@ -1,4 +1,7 @@
-from compwa_policy.python.pytest import _deny_ini_options
+import pytest
+
+from compwa_policy.errors import PrecommitError
+from compwa_policy.python.pytest import _deny_ini_options, _update_codecov_settings
 from compwa_policy.utilities.pyproject import ModifiablePyproject
 
 
@@ -9,3 +12,19 @@ def test_deny_ini_options_ignores_missing_pytest_table():
     """) as pyproject:
         _deny_ini_options(pyproject)
         assert pyproject.changelog == []
+
+
+def test_update_codecov_settings_can_disable_branch_coverage():
+    with (
+        pytest.raises(PrecommitError, match=r"Updated pytest coverage settings"),
+        ModifiablePyproject.load("""
+            [project]
+            name = "x"
+
+            [dependency-groups]
+            test = ["pytest-cov"]
+        """) as pyproject,
+    ):
+        _update_codecov_settings(pyproject, branch_coverage=False)
+    coverage = pyproject.get_table("tool.coverage.run")
+    assert coverage["branch"] is False

tests/test_cli.py

@@ -31,6 +31,7 @@ def test_build_arguments_defaults() -> None:
     assert args.type_checker == set()
     assert args.excluded_python_versions == set()
     assert args.keep_workflow == set()
+    assert args.branch_coverage is True
     assert args.python is None
 
 
@@ -73,6 +74,7 @@ def test_flatten_nested_tables(
             package-manager = "pixi"
 
             [tool.compwa.policy.python]
+            branch-coverage = false
             imports-on-top = true
             type-checker = ["mypy", "pyright"]
 
@@ -90,6 +92,7 @@ def test_flatten_nested_tables(
         assert _read_policy_config() == {
             "dev_python_version": "3.12",
             "package_manager": "pixi",
+            "branch_coverage": False,
             "imports_on_top": True,
             "type_checker": ["mypy", "pyright"],
             "no_binder": True,
@@ -111,6 +114,7 @@ def test_pyproject_overrides_defaults(
             dev-python-version = "3.12"
 
             [tool.compwa.policy.python]
+            branch-coverage = false
             type-checker = ["mypy", "pyright"]
 
             [tool.compwa.policy.setup.env]
@@ -119,6 +123,7 @@ def test_pyproject_overrides_defaults(
         )
         args = build_arguments()
         assert args.dev_python_version == "3.12"
+        assert args.branch_coverage is False
         assert args.type_checker == {"mypy", "pyright"}
         assert args.environment_variables == "PYTHONHASHSEED=0"
 
@@ -136,6 +141,19 @@ def test_cli_overrides_pyproject(
         assert load_settings(dev_python_version="3.11").dev_python_version == "3.11"
         assert load_settings(dev_python_version=None).dev_python_version == "3.12"
 
+    def test_branch_coverage_cli_overrides_pyproject(
+        self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        _write_policy(
+            tmp_path,
+            monkeypatch,
+            """
+            [tool.compwa.policy.python]
+            branch-coverage = false
+            """,
+        )
+        assert load_settings(branch_coverage=True).branch_coverage is True
+
     def test_unknown_option_is_rejected(
         self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
     ) -> None:
@@ -165,6 +183,7 @@ class TestBuildPolicy:
     def test_groups_into_sub_tables(self) -> None:
         policy = _build_policy([
             "--allow-labels",
+            "--no-branch-coverage",
             "--keep-local-precommit",
             "--no-pypi",
             "--pytest-single-threaded",
@@ -174,7 +193,11 @@ def test_groups_into_sub_tables(self) -> None:
         ])
         assert policy == {
             "github": {"allow-labels": True, "no-pypi": True},
-            "python": {"keep-local-precommit": True, "type-checker": ["ty"]},
+            "python": {
+                "branch-coverage": False,
+                "keep-local-precommit": True,
+                "type-checker": ["ty"],
+            },
             "pytest-single-threaded": True,
             "repo-name": "policy",
             "repo-title": "ComPWA repository policy",