feat: add per-library override configurations to .librarian/config.yaml (#2039)

chingor13 · web-flow · commit 4f8141cb838a · 2025-09-11T09:21:09.000-07:00
feat: add LibraryConfigFor(libraryID string) Step 1 towards #1704 Fixes #2040
diff --git a/internal/config/librarian_config.go b/internal/config/librarian_config.go
@@ -26,7 +26,14 @@ const (
 
 // LibrarianConfig defines the contract for the config.yaml file.
 type LibrarianConfig struct {
-	GlobalFilesAllowlist []*GlobalFile `yaml:"global_files_allowlist"`
+	GlobalFilesAllowlist []*GlobalFile    `yaml:"global_files_allowlist"`
+	Libraries            []*LibraryConfig `yaml:"libraries"`
+}
+
+// LibraryConfig defines configuration for a single library, identified by its ID.
+type LibraryConfig struct {
+	LibraryID   string `yaml:"id"`
+	NextVersion string `yaml:"next_version"`
 }
 
 // GlobalFile defines the global files in language repositories.
@@ -55,3 +62,13 @@ func (g *LibrarianConfig) Validate() error {
 
 	return nil
 }
+
+// LibraryConfigFor finds the LibraryConfig entry for a given LibraryID.
+func (g *LibrarianConfig) LibraryConfigFor(LibraryID string) *LibraryConfig {
+	for _, lib := range g.Libraries {
+		if lib.LibraryID == LibraryID {
+			return lib
+		}
+	}
+	return nil
+}
diff --git a/internal/config/librarian_config_test.go b/internal/config/librarian_config_test.go
@@ -17,6 +17,8 @@ package config
 import (
 	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestGlobalConfig_Validate(t *testing.T) {
@@ -100,3 +102,67 @@ func TestGlobalConfig_Validate(t *testing.T) {
 		})
 	}
 }
+
+func TestLibraryConfigFor(t *testing.T) {
+	cases := []struct {
+		name          string
+		config        *LibrarianConfig
+		LibraryID     string
+		wantLibrary   *LibraryConfig
+		wantErr       bool
+		wantErrSubstr string
+	}{
+		{
+			name: "library found",
+			config: &LibrarianConfig{
+				Libraries: []*LibraryConfig{
+					{LibraryID: "lib1", NextVersion: "1.0.0"},
+					{LibraryID: "lib2", NextVersion: "2.0.0"},
+				},
+			},
+			LibraryID:   "lib1",
+			wantLibrary: &LibraryConfig{LibraryID: "lib1", NextVersion: "1.0.0"},
+		},
+		{
+			name: "library not found",
+			config: &LibrarianConfig{
+				Libraries: []*LibraryConfig{
+					{LibraryID: "lib1", NextVersion: "1.0.0"},
+					{LibraryID: "lib2", NextVersion: "2.0.0"},
+				},
+			},
+			LibraryID:   "lib3",
+			wantLibrary: nil,
+		},
+		{
+			name: "empty libraries",
+			config: &LibrarianConfig{
+				Libraries: []*LibraryConfig{},
+			},
+			LibraryID:   "lib1",
+			wantLibrary: nil,
+		},
+		{
+			name: "multiple libraries with target in middle",
+			config: &LibrarianConfig{
+				Libraries: []*LibraryConfig{
+					{LibraryID: "lib1", NextVersion: "1.0.0"},
+					{LibraryID: "lib2", NextVersion: "2.0.0"},
+					{LibraryID: "lib3", NextVersion: "3.0.0"},
+				},
+			},
+			LibraryID:   "lib2",
+			wantLibrary: &LibraryConfig{LibraryID: "lib2", NextVersion: "2.0.0"},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			gotLibrary := tc.config.LibraryConfigFor(tc.LibraryID)
+
+			if diff := cmp.Diff(tc.wantLibrary, gotLibrary); diff != "" {
+				t.Errorf("LibraryConfigFor() mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
