feat(ci): add --config option and MERGIFY_CONFIG_PATH envvar to git-refs and scopes

mergify_cli/ci/cli.py

@@ -218,7 +218,8 @@ def git_refs() -> None:
 @click.option(
     "--config",
     "config_path",
-    type=click.Path(),
+    type=click.Path(dir_okay=False),
+    envvar="MERGIFY_CONFIG_PATH",
     default=detector.get_mergify_config_path,
     help="Path to YAML config file.",
 )
@@ -242,11 +243,19 @@ def scopes(
     head: str | None = None,
     base: str | None = None,
 ) -> None:
+    # Empty envvar (MERGIFY_CONFIG_PATH="") should fall back to autodetect
+    if config_path is not None and not config_path:
+        config_path = detector.get_mergify_config_path()
+
     if config_path is None:
         locations = ", ".join(detector.MERGIFY_CONFIG_PATHS)
         msg = f"Mergify configuration file not found. Looked in: {locations}"
         raise click.ClickException(msg)
 
+    if not pathlib.Path(config_path).is_file():
+        msg = f"Config file '{config_path}' does not exist."
+        raise click.ClickException(msg)
+
     if base or head:
         ref = git_refs_detector.References(
             base=base,

mergify_cli/tests/ci/test_cli.py

@@ -490,6 +490,25 @@ def test_scopes_send(
     assert sorted(payload["scopes"]) == ["backend", "foobar", "frontend"]
 
 
+def test_scopes_empty_mergify_config_env_uses_autodetection(
+    tmp_path: pathlib.Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """When MERGIFY_CONFIG_PATH is set but empty, the config should be auto-detected."""
+    config_file = tmp_path / ".mergify.yml"
+    config_file.write_text("scopes:\n  source:\n    manual:\n")
+
+    monkeypatch.chdir(tmp_path)
+    monkeypatch.setenv("MERGIFY_CONFIG_PATH", "")
+
+    runner = testing.CliRunner()
+    result = runner.invoke(ci_cli.scopes, ["--base", "old", "--head", "new"])
+
+    # The command found the auto-detected config and ran (source is manual so exit 1)
+    assert result.exit_code == 1
+    assert "source `manual` has been set" in result.output
+
+
 def test_git_refs(
     tmp_path: pathlib.Path,
     monkeypatch: pytest.MonkeyPatch,