feat(config): discover .github/poutine.yml as a config path (#424)

---------

Signed-off-by: graelo <graelo@graelo.cc>

Author: graelo

README.md

@@ -111,7 +111,7 @@ poutine analyze_org my-org/project --token "$GL_TOKEN" --scm gitlab --scm-base-u
 --scm                SCM platform (default: github, gitlab)
 --scm-base-url       Base URI of the self-hosted SCM instance
 --threads            Number of threads to use (default: 2)
---config             Path to the configuration file (default: .poutine.yml)
+--config             Path to the configuration file (default: .poutine.yml in the working directory, or .github/poutine.yml)
 --skip               Add rules to the skip list for the current run (can be specified multiple times)
 --verbose            Enable debug logging
 --fail-on-violation  Exit with a non-zero code (10) when violations are found
@@ -125,7 +125,7 @@ See [.poutine.sample.yml](.poutine.sample.yml) for an example configuration file
 
 #### Configuration
 
-Create a `.poutine.yml` configuration file in your current working directory, or use a custom path with the `--config` flag:
+Create a `.poutine.yml` configuration file in your current working directory, or keep it alongside your other GitHub metadata at `.github/poutine.yml` — both are auto-discovered. When both exist, `.poutine.yml` at the repo root wins. To use a custom path, pass the `--config` flag (which takes precedence over both):
 
 ```bash
 poutine analyze_local . --config my-config.yml

cmd/config_discovery_test.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFindDefaultConfigFile_NoConfig(t *testing.T) {
+	dir := t.TempDir()
+	assert.Empty(t, findDefaultConfigFile(dir))
+}
+
+func TestFindDefaultConfigFile_RootYml(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, ".poutine.yml")
+	require.NoError(t, os.WriteFile(path, []byte("ignoreForks: true\n"), 0o644))
+
+	assert.Equal(t, path, findDefaultConfigFile(dir))
+}
+
+func TestFindDefaultConfigFile_RootYaml(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, ".poutine.yaml")
+	require.NoError(t, os.WriteFile(path, []byte("ignoreForks: true\n"), 0o644))
+
+	assert.Equal(t, path, findDefaultConfigFile(dir))
+}
+
+func TestFindDefaultConfigFile_GithubDir(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.Mkdir(filepath.Join(dir, ".github"), 0o755))
+	path := filepath.Join(dir, ".github", "poutine.yml")
+	require.NoError(t, os.WriteFile(path, []byte("ignoreForks: true\n"), 0o644))
+
+	assert.Equal(t, path, findDefaultConfigFile(dir))
+}
+
+func TestFindDefaultConfigFile_RootTakesPrecedence(t *testing.T) {
+	dir := t.TempDir()
+	rootPath := filepath.Join(dir, ".poutine.yml")
+	require.NoError(t, os.WriteFile(rootPath, []byte("ignoreForks: true\n"), 0o644))
+
+	require.NoError(t, os.Mkdir(filepath.Join(dir, ".github"), 0o755))
+	ghPath := filepath.Join(dir, ".github", "poutine.yml")
+	require.NoError(t, os.WriteFile(ghPath, []byte("ignoreForks: false\n"), 0o644))
+
+	assert.Equal(t, rootPath, findDefaultConfigFile(dir),
+		"`.poutine.yml` at repo root must take precedence over `.github/poutine.yml`")
+}
+
+// TestFindDefaultConfigFile_IgnoresDirectoryNamedLikeConfig ensures that a
+// directory (rather than a file) at a candidate path is skipped — otherwise
+// a stray `.poutine.yml/` dir would be wrongly reported as the config file.
+func TestFindDefaultConfigFile_IgnoresDirectoryNamedLikeConfig(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.Mkdir(filepath.Join(dir, ".poutine.yml"), 0o755))
+
+	require.NoError(t, os.Mkdir(filepath.Join(dir, ".github"), 0o755))
+	ghPath := filepath.Join(dir, ".github", "poutine.yml")
+	require.NoError(t, os.WriteFile(ghPath, []byte("ignoreForks: true\n"), 0o644))
+
+	assert.Equal(t, ghPath, findDefaultConfigFile(dir))
+}

cmd/root.go

@@ -138,7 +138,7 @@ func init() {
 		}
 	}
 
-	RootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is .poutine.yml in the current directory)")
+	RootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is .poutine.yml in the current directory or .github/poutine.yml)")
 	RootCmd.PersistentFlags().StringVarP(&Format, "format", "f", "pretty", "Output format (pretty, json, sarif)")
 	RootCmd.PersistentFlags().BoolVarP(&Verbose, "verbose", "v", false, "Enable verbose logging")
 	RootCmd.PersistentFlags().StringVarP(&ScmProvider, "scm", "s", "github", "SCM platform (github, gitlab)")
@@ -153,20 +153,20 @@ func init() {
 
 func initConfig() {
 	viper.AutomaticEnv()
-	if cfgFile != "" {
-		viper.SetConfigFile(cfgFile)
-	} else {
-		viper.AddConfigPath(".")
-		viper.SetConfigName(".poutine")
+
+	configPath := cfgFile
+	if configPath == "" {
+		configPath = findDefaultConfigFile(".")
+	}
+
+	if configPath == "" {
+		return
 	}
 
+	viper.SetConfigFile(configPath)
 	if err := viper.ReadInConfig(); err != nil {
-		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
-			return
-		} else {
-			log.Error().Err(err).Msg("Can't read config")
-			os.Exit(1)
-		}
+		log.Error().Err(err).Msg("Can't read config")
+		os.Exit(1)
 	}
 
 	if err := viper.Unmarshal(&config); err != nil {
@@ -175,6 +175,31 @@ func initConfig() {
 	}
 }
 
+// findDefaultConfigFile returns the path of the first default config file
+// found under baseDir, in order of precedence:
+//  1. <baseDir>/.poutine.<ext>        (working directory)
+//  2. <baseDir>/.github/poutine.<ext> (GitHub convention — no leading dot)
+//
+// Extensions are those supported by viper (yml, yaml, json, toml, ...).
+// Returns "" if no default config file is found.
+func findDefaultConfigFile(baseDir string) string {
+	candidates := []struct {
+		dir, name string
+	}{
+		{baseDir, ".poutine"},
+		{filepath.Join(baseDir, ".github"), "poutine"},
+	}
+	for _, c := range candidates {
+		for _, ext := range viper.SupportedExts {
+			path := filepath.Join(c.dir, c.name+"."+ext)
+			if info, err := os.Stat(path); err == nil && !info.IsDir() {
+				return path
+			}
+		}
+	}
+	return ""
+}
+
 func cleanup() {
 	log.Debug().Msg("Cleaning up temp directories")
 	globPattern := filepath.Join(os.TempDir(), analyze.TEMP_DIR_PREFIX)