fix(devtools/cmd/migrate-sidekick): add hardcoded exclusion list for veneer detection (#3317)

Adds a hardcoded list to excluded when identifying veneer libraries. The
migrate tool treats any library with a Cargo.toml file outside the
src/generated directory as a veneer library. This heuristic approach is
a bit too broad and included libraries that are not generated:
-
[echo-server](https://github.com/googleapis/google-cloud-rust/blob/main/src/gax-internal/echo-server/src/lib.rs):
test util that is handwritten
-
[gcp-sdk](https://github.com/googleapis/google-cloud-rust/blob/main/src/root/Cargo.toml):
workspace Crate

For #3313

Author: zhumin8

devtools/cmd/migrate-sidekick/main.go

@@ -51,6 +51,11 @@ var (
 	errUnableToCalculateOutputPath = errors.New("unable to calculate output path")
 )
 
+var excludedVeneerLibraries = map[string]struct{}{
+	"echo-server": {},
+	"gcp-sdk":     {},
+}
+
 // SidekickConfig represents the structure of a .sidekick.toml file.
 type SidekickConfig struct {
 	General struct {
@@ -505,6 +510,12 @@ func buildVeneer(files []string) (map[string]*config.Library, error) {
 		if err != nil {
 			return nil, err
 		}
+
+		if _, ok := excludedVeneerLibraries[cargo.Package.Name]; ok {
+			slog.Info("Excluding hardcoded veneer library", "name", cargo.Package.Name)
+			continue
+		}
+
 		dir := filepath.Dir(file)
 		rustModules, err := buildModules(dir)
 		if err != nil {

devtools/cmd/migrate-sidekick/main_test.go

@@ -507,6 +507,58 @@ func TestBuildVeneer(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "excluded_library",
+			files: []string{
+				"testdata/build-veneer/success/lib-1/Cargo.toml",
+				"testdata/build-veneer/success/echo-server/Cargo.toml",
+			},
+			want: map[string]*config.Library{
+				"google-cloud-storage": {
+					Name:          "google-cloud-storage",
+					Veneer:        true,
+					Output:        "testdata/build-veneer/success/lib-1",
+					Version:       "1.5.0",
+					CopyrightYear: "2025",
+					Rust: &config.RustCrate{
+						Modules: []*config.RustModule{
+							{
+								DisabledRustdocWarnings: []string{},
+								GenerateSetterSamples:   true,
+								ModuleRoots:             nil,
+								HasVeneer:               true,
+								IncludedIds: []string{
+									".google.storage.v2.Storage.DeleteBucket",
+									".google.storage.v2.Storage.GetBucket",
+									".google.storage.v2.Storage.CreateBucket",
+									".google.storage.v2.Storage.ListBuckets",
+								},
+								IncludeGrpcOnlyMethods: true,
+								NameOverrides:          ".google.storage.v2.Storage=StorageControl",
+								Output:                 "testdata/build-veneer/success/lib-1/dir-1",
+								RoutingRequired:        true,
+								ServiceConfig:          "google/storage/v2/storage_v2.yaml",
+								SkippedIds:             []string{".google.iam.v1.ResourcePolicyMember"},
+								Source:                 "google/storage/v2",
+								Template:               "grpc-client",
+								TitleOverride:          "Cloud Firestore API",
+							},
+							{
+								GenerateSetterSamples: false,
+								ModulePath:            "crate::generated::gapic_control::model",
+								ModuleRoots: map[string]string{
+									"project-root": ".",
+								},
+								NameOverrides: ".google.storage.control.v2.IntelligenceConfig.Filter.cloud_storage_buckets=CloudStorageBucketsOneOf",
+								Output:        "testdata/build-veneer/success/lib-1/dir-2/dirdir-2",
+								Source:        "google/storage/control/v2",
+								Template:      "convert-prost",
+							},
+						},
+					},
+				},
+			},
+		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			got, err := buildVeneer(test.files)

devtools/cmd/migrate-sidekick/testdata/build-veneer/success/echo-server/Cargo.toml

@@ -0,0 +1,3 @@
+[package]
+name = "echo-server"
+version = "0.1.0"