feat(dart): Can config dart export (#2641)

brianquinlan · devoncarew · web-flow · commit 97eacd29a775 · 2025-10-21T15:44:44.000-07:00
This allows packages to export symbols from other packages e.g.

```
extra-exports = "export 'package:google_cloud_gax/gax.dart' show Status;"
```

```dart
...
import 'package:google_cloud_gax/gax.dart';
import 'package:google_cloud_gax/src/encoding.dart';
import 'package:google_cloud_protobuf/protobuf.dart';

export 'package:google_cloud_gax/gax.dart' show Status;

part 'src/rpc.p.dart';
...
```

---------

Signed-off-by: Brian Quinlan &lt;bquinlan@google.com&gt;
Co-authored-by: Devon Carew &lt;devoncarew@google.com&gt;
diff --git a/internal/sidekick/internal/dart/annotate.go b/internal/sidekick/internal/dart/annotate.go
@@ -58,6 +58,9 @@ type modelAnnotations struct {
 	ReadMeQuickstartText       string
 	IssueTrackerURL            string
 	ApiKeyEnvironmentVariables []string
+	// Dart `export` statements e.g.
+	// ["export 'package:google_cloud_gax/gax.dart' show Any", "export 'package:google_cloud_gax/gax.dart' show Status"]
+	Exports []string
 }
 
 // HasServices returns true if the model has services.
@@ -230,6 +233,7 @@ func (annotate *annotateModel) annotateModel(options map[string]string) error {
 		readMeQuickstartText       string
 		issueTrackerURL            string
 		apiKeyEnvironmentVariables = []string{}
+		exports                    = []string{}
 	)
 
 	for key, definition := range options {
@@ -254,6 +258,13 @@ func (annotate *annotateModel) annotateModel(options map[string]string) error {
 			packageVersion = definition
 		case key == "part-file":
 			partFileReference = definition
+		case key == "extra-exports":
+			// extra-export = "export 'package:google_cloud_gax/gax.dart' show Any; export 'package:google_cloud_gax/gax.dart' show Status;"
+			// Dart `export` statements that should be appended after any imports.
+			exports = strings.FieldsFunc(definition, func(c rune) bool { return c == ';' })
+			for i := range exports {
+				exports[i] = strings.TrimSpace(exports[i])
+			}
 		case key == "dev-dependencies":
 			devDependencies = strings.Split(definition, ",")
 		case key == "not-for-publication":
@@ -373,6 +384,7 @@ func (annotate *annotateModel) annotateModel(options map[string]string) error {
 		ReadMeAfterTitleText:       readMeAfterTitleText,
 		ReadMeQuickstartText:       readMeQuickstartText,
 		ApiKeyEnvironmentVariables: apiKeyEnvironmentVariables,
+		Exports:                    exports,
 	}
 
 	model.Codec = ann
diff --git a/internal/sidekick/internal/dart/annotate_test.go b/internal/sidekick/internal/dart/annotate_test.go
@@ -80,6 +80,17 @@ func TestAnnotateModel_Options(t *testing.T) {
 				}
 			},
 		},
+		{
+			map[string]string{"extra-exports": "export 'package:google_cloud_gax/gax.dart' show Any; export 'package:google_cloud_gax/gax.dart' show Status;"},
+			func(t *testing.T, am *annotateModel) {
+				codec := model.Codec.(*modelAnnotations)
+				if diff := cmp.Diff([]string{
+					"export 'package:google_cloud_gax/gax.dart' show Any",
+					"export 'package:google_cloud_gax/gax.dart' show Status"}, codec.Exports); diff != "" {
+					t.Errorf("mismatch in Codec.Exports (-want, +got)\n:%s", diff)
+				}
+			},
+		},
 		{
 			map[string]string{"version": "1.2.3"},
 			func(t *testing.T, am *annotateModel) {
diff --git a/internal/sidekick/internal/dart/templates/lib/main.dart.mustache b/internal/sidekick/internal/dart/templates/lib/main.dart.mustache
@@ -28,6 +28,11 @@ library;
 {{#Codec.Imports}}
 {{{.}}}
 {{/Codec.Imports}}
+
+{{#Codec.Exports}}
+{{{.}}};
+{{/Codec.Exports}}
+
 {{#Codec.PartFileReference}}
 
 part '{{Codec.PartFileReference}}';
