Bundle maven packaging deps in java plugins

internal/cmd/fetcher/main.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/bufbuild/plugins/internal/docker"
 	"github.com/bufbuild/plugins/internal/fetchclient"
+	"github.com/bufbuild/plugins/internal/maven"
 	"github.com/bufbuild/plugins/internal/plugin"
 	"github.com/bufbuild/plugins/internal/source"
 )
@@ -131,6 +132,9 @@ func postProcessCreatedPlugins(ctx context.Context, logger *slog.Logger, plugins
 	}
 	for _, plugin := range plugins {
 		newPluginRef := plugin.String()
+		if err := regenerateMavenDeps(plugin); err != nil {
+			return fmt.Errorf("failed to regenerate maven deps for %s: %w", newPluginRef, err)
+		}
 		if err := runGoModTidy(ctx, logger, plugin); err != nil {
 			return fmt.Errorf("failed to run go mod tidy for %s: %w", newPluginRef, err)
 		}
@@ -273,6 +277,14 @@ func recreateSwiftPackageResolved(ctx context.Context, logger *slog.Logger, plug
 	return nil
 }
 
+// regenerateMavenDeps regenerates the pom.xml and Dockerfile's maven-deps
+// stage from the plugin's buf.plugin.yaml.
+func regenerateMavenDeps(plugin createdPlugin) error {
+	versionDir := filepath.Join(plugin.pluginDir, plugin.newVersion)
+	pluginsDir := filepath.Dir(filepath.Dir(plugin.pluginDir))
+	return maven.RegenerateMavenDeps(versionDir, pluginsDir)
+}
+
 // runPluginTests runs 'make test PLUGINS="org/name:v<new>"' in order to generate plugin.sum files.
 func runPluginTests(ctx context.Context, logger *slog.Logger, plugins []createdPlugin) error {
 	pluginsEnv := make([]string, 0, len(plugins))

internal/cmd/fetcher/main_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"encoding/xml"
 	"log/slog"
 	"os"
 	"path/filepath"
@@ -15,6 +16,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/bufbuild/plugins/internal/maven"
 	"github.com/bufbuild/plugins/internal/source"
 )
 
@@ -358,3 +360,260 @@ func newTestContainer(t *testing.T, root string) appext.Container {
 	logger := slog.New(slog.NewTextHandler(testWriter{t}, &slog.HandlerOptions{Level: slog.LevelDebug}))
 	return appext.NewContainer(nameContainer, logger)
 }
+
+func TestRegenerateMavenDepsWithPluginDeps(t *testing.T) {
+	t.Parallel()
+	tmpDir := t.TempDir()
+
+	// Setup: base-plugin has Maven deps including an additional lite runtime.
+	baseDir := filepath.Join(tmpDir, "plugins", "test", "base-plugin", "v1.0.0")
+	require.NoError(t, os.MkdirAll(baseDir, 0755))
+	baseYAML := `version: v1
+name: buf.build/test/base-plugin
+plugin_version: v1.0.0
+output_languages:
+  - java
+registry:
+  maven:
+    deps:
+      - com.google.protobuf:protobuf-java:4.33.5
+    additional_runtimes:
+      - name: lite
+        deps:
+          - com.google.protobuf:protobuf-javalite:4.33.5
+          - build.buf:protobuf-javalite:4.33.5
+        opts: [lite]
+`
+	require.NoError(t, os.WriteFile(filepath.Join(baseDir, "buf.plugin.yaml"), []byte(baseYAML), 0644))
+
+	// Setup: consumer-plugin depends on base-plugin and has its own Maven
+	// deps plus a lite runtime. The Dockerfile has a maven-deps stage.
+	consumerDir := filepath.Join(tmpDir, "plugins", "test", "consumer-plugin", "v1.0.0")
+	require.NoError(t, os.MkdirAll(consumerDir, 0755))
+	consumerYAML := `version: v1
+name: buf.build/test/consumer-plugin
+plugin_version: v1.0.0
+deps:
+  - plugin: buf.build/test/base-plugin:v1.0.0
+output_languages:
+  - kotlin
+registry:
+  maven:
+    compiler:
+      kotlin:
+        version: 1.8.22
+    deps:
+      - com.google.protobuf:protobuf-kotlin:4.33.5
+    additional_runtimes:
+      - name: lite
+        deps:
+          - com.google.protobuf:protobuf-kotlin-lite:4.33.5
+        opts: [lite]
+`
+	require.NoError(t, os.WriteFile(filepath.Join(consumerDir, "buf.plugin.yaml"), []byte(consumerYAML), 0644))
+
+	dockerfile := `# syntax=docker/dockerfile:1.19
+FROM debian:bookworm AS build
+RUN echo hello
+
+FROM scratch
+COPY --from=build /app .
+ENTRYPOINT ["/app"]
+`
+	require.NoError(t, os.WriteFile(filepath.Join(consumerDir, "Dockerfile"), []byte(dockerfile), 0644))
+
+	// Run regenerateMavenDeps on the consumer plugin
+	err := regenerateMavenDeps(createdPlugin{
+		org:        "test",
+		name:       "consumer-plugin",
+		pluginDir:  filepath.Join(tmpDir, "plugins", "test", "consumer-plugin"),
+		newVersion: "v1.0.0",
+	})
+	require.NoError(t, err)
+
+	// Verify the maven-deps stage was inserted into the Dockerfile.
+	dockerfileBytes, err := os.ReadFile(filepath.Join(consumerDir, "Dockerfile"))
+	require.NoError(t, err)
+	assert.Contains(t, string(dockerfileBytes), "FROM "+maven.MavenImage+" AS maven-deps")
+	assert.Contains(t, string(dockerfileBytes), "COPY --from=maven-deps /root/.m2/repository /maven-repository")
+
+	// Read and parse pom.xml to verify deps include versions.
+	pomBytes, err := os.ReadFile(filepath.Join(consumerDir, "pom.xml"))
+	require.NoError(t, err)
+	var pom testPOMProject
+	require.NoError(t, xml.Unmarshal(pomBytes, &pom))
+	var depVersions []string
+	for _, dep := range pom.Dependencies {
+		depVersions = append(depVersions, dep.String())
+	}
+	// Consumer's own deps should be present.
+	assert.Contains(t, depVersions, "com.google.protobuf:protobuf-kotlin:4.33.5")
+	assert.Contains(t, depVersions, "com.google.protobuf:protobuf-kotlin-lite:4.33.5")
+	// Base plugin's main deps should be merged in.
+	assert.Contains(t, depVersions, "com.google.protobuf:protobuf-java:4.33.5")
+	// Base plugin's lite runtime deps should be merged into the
+	// matching lite runtime section.
+	assert.Contains(t, depVersions, "com.google.protobuf:protobuf-javalite:4.33.5")
+	assert.Contains(t, depVersions, "build.buf:protobuf-javalite:4.33.5")
+}
+
+func TestMergeDepsMavenDepsTransitive(t *testing.T) {
+	t.Parallel()
+	tmpDir := t.TempDir()
+
+	// Setup: grandparent -> parent -> child chain
+	grandparentDir := filepath.Join(tmpDir, "plugins", "test", "grandparent", "v1.0.0")
+	require.NoError(t, os.MkdirAll(grandparentDir, 0755))
+	grandparentYAML := `version: v1
+name: buf.build/test/grandparent
+plugin_version: v1.0.0
+output_languages:
+  - java
+registry:
+  maven:
+    deps:
+      - org.example:grandparent-dep:1.0.0
+`
+	require.NoError(t, os.WriteFile(filepath.Join(grandparentDir, "buf.plugin.yaml"), []byte(grandparentYAML), 0644))
+
+	parentDir := filepath.Join(tmpDir, "plugins", "test", "parent", "v1.0.0")
+	require.NoError(t, os.MkdirAll(parentDir, 0755))
+	parentYAML := `version: v1
+name: buf.build/test/parent
+plugin_version: v1.0.0
+deps:
+  - plugin: buf.build/test/grandparent:v1.0.0
+output_languages:
+  - java
+registry:
+  maven:
+    deps:
+      - org.example:parent-dep:1.0.0
+`
+	require.NoError(t, os.WriteFile(filepath.Join(parentDir, "buf.plugin.yaml"), []byte(parentYAML), 0644))
+
+	childDir := filepath.Join(tmpDir, "plugins", "test", "child", "v1.0.0")
+	require.NoError(t, os.MkdirAll(childDir, 0755))
+	childYAML := `version: v1
+name: buf.build/test/child
+plugin_version: v1.0.0
+deps:
+  - plugin: buf.build/test/parent:v1.0.0
+output_languages:
+  - java
+registry:
+  maven:
+    deps:
+      - org.example:child-dep:1.0.0
+`
+	require.NoError(t, os.WriteFile(filepath.Join(childDir, "buf.plugin.yaml"), []byte(childYAML), 0644))
+
+	// Parse the child plugin config
+	childConfig, err := bufremotepluginconfig.ParseConfig(
+		filepath.Join(childDir, "buf.plugin.yaml"),
+	)
+	require.NoError(t, err)
+
+	// Merge transitive deps
+	pluginsDir := filepath.Join(tmpDir, "plugins")
+	err = maven.MergeTransitiveDeps(childConfig, pluginsDir)
+	require.NoError(t, err)
+
+	// Child should now have all three deps: child-dep, parent-dep,
+	// grandparent-dep (transitive through parent)
+	var artifactIDs []string
+	for _, dep := range childConfig.Registry.Maven.Deps {
+		artifactIDs = append(artifactIDs, dep.ArtifactID)
+	}
+	assert.Contains(t, artifactIDs, "child-dep")
+	assert.Contains(t, artifactIDs, "parent-dep")
+	assert.Contains(t, artifactIDs, "grandparent-dep")
+}
+
+func TestDeduplicateAllDeps(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name    string
+		deps    []bufremotepluginconfig.MavenDependencyConfig
+		want    []bufremotepluginconfig.MavenDependencyConfig
+		wantErr string
+	}{
+		{
+			name: "no duplicates",
+			deps: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+				{GroupID: "com.example", ArtifactID: "b", Version: "1.0"},
+			},
+			want: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+				{GroupID: "com.example", ArtifactID: "b", Version: "1.0"},
+			},
+		},
+		{
+			name: "exact duplicate removed",
+			deps: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+			},
+			want: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+			},
+		},
+		{
+			name: "version conflict returns error",
+			deps: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+				{GroupID: "com.example", ArtifactID: "a", Version: "2.0"},
+			},
+			wantErr: "duplicate Maven dependency com.example:a with conflicting versions",
+		},
+		{
+			name: "different classifiers are distinct",
+			deps: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0", Classifier: "sources"},
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+			},
+			want: []bufremotepluginconfig.MavenDependencyConfig{
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0", Classifier: "sources"},
+				{GroupID: "com.example", ArtifactID: "a", Version: "1.0"},
+			},
+		},
+		{
+			name: "nil input",
+			deps: nil,
+			want: nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			config := &bufremotepluginconfig.MavenRegistryConfig{
+				Deps: tt.deps,
+			}
+			err := maven.DeduplicateAllDeps(config)
+			if tt.wantErr != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tt.wantErr)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, config.Deps)
+		})
+	}
+}
+
+// testPOMProject mirrors the Maven POM structure for test assertions.
+type testPOMProject struct {
+	XMLName      xml.Name  `xml:"project"`
+	Dependencies []testDep `xml:"dependencies>dependency"`
+}
+
+type testDep struct {
+	GroupID    string `xml:"groupId"`
+	ArtifactID string `xml:"artifactId"`
+	Version    string `xml:"version"`
+}
+
+func (d testDep) String() string {
+	return d.GroupID + ":" + d.ArtifactID + ":" + d.Version
+}

internal/cmd/regenerate-maven-poms/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+
+	"buf.build/go/app"
+	"buf.build/go/app/appcmd"
+
+	"github.com/bufbuild/plugins/internal/maven"
+)
+
+func main() {
+	appcmd.Main(context.Background(), newCommand("regenerate-maven-poms"))
+}
+
+func newCommand(name string) *appcmd.Command {
+	return &appcmd.Command{
+		Use:   name + " <plugin-dir> [<plugin-dir>...]",
+		Short: "Regenerates maven-deps POM and Dockerfile stage for Java/Kotlin plugins",
+		Args:  appcmd.MinimumNArgs(1),
+		Run: func(_ context.Context, container app.Container) error {
+			for i := range container.NumArgs() {
+				pluginDir := container.Arg(i)
+				// pluginDir is e.g. plugins/org/name/version, so
+				// plugins root is 3 levels up.
+				pluginsDir := filepath.Dir(filepath.Dir(filepath.Dir(pluginDir)))
+				if err := maven.RegenerateMavenDeps(pluginDir, pluginsDir); err != nil {
+					return fmt.Errorf("failed to regenerate %s: %w", pluginDir, err)
+				}
+				fmt.Fprintf(container.Stdout(), "regenerated: %s\n", pluginDir)
+			}
+			return nil
+		},
+	}
+}