[gazelle] Use the index file generated by rules_jvm_external to better find third party deps

Author: shs96c

java/gazelle/configure.go

@@ -25,6 +25,7 @@ type Configurer struct {
 	annotationToAttribute annotationToAttribute
 	annotationToWrapper   annotationToWrapper
 	mavenInstallFile      string
+	javaIndexFile         string
 }
 
 func NewConfigurer(lang *javaLang) *Configurer {
@@ -39,6 +40,7 @@ func (jc *Configurer) RegisterFlags(fs *flag.FlagSet, cmd string, c *config.Conf
 	fs.Var(&jc.annotationToAttribute, "java-annotation-to-attribute", "Mapping of annotations (on test classes) to attributes which should be set for that test rule. Examples: com.example.annotations.FlakyTest=flaky=True com.example.annotations.SlowTest=timeout=\"long\"")
 	fs.Var(&jc.annotationToWrapper, "java-annotation-to-wrapper", "Mapping of annotations (on test classes) to wrapper rules which should be used around the test rule. Example: com.example.annotations.RequiresNetwork=@some//wrapper:file.bzl=requires_network")
 	fs.StringVar(&jc.mavenInstallFile, "java-maven-install-file", "", "Path of the maven_install.json file. Defaults to \"maven_install.json\".")
+	fs.StringVar(&jc.javaIndexFile, "java-index-file", "", "Path of the maven_index.json file. Defaults to \"maven_index.json\".")
 }
 
 func (jc *Configurer) CheckFlags(fs *flag.FlagSet, c *config.Config) error {
@@ -54,6 +56,9 @@ func (jc *Configurer) CheckFlags(fs *flag.FlagSet, c *config.Config) error {
 	if jc.mavenInstallFile != "" {
 		cfgs[""].SetMavenInstallFile(jc.mavenInstallFile)
 	}
+	if jc.javaIndexFile != "" {
+		cfgs[""].SetMavenIndexFile(jc.javaIndexFile)
+	}
 	return nil
 }
 
@@ -62,6 +67,7 @@ func (jc *Configurer) KnownDirectives() []string {
 		javaconfig.JavaExcludeArtifact,
 		javaconfig.JavaExtensionDirective,
 		javaconfig.JavaMavenInstallFile,
+		javaconfig.JavaIndexFile,
 		javaconfig.JavaModuleGranularityDirective,
 		javaconfig.JavaTestFileSuffixes,
 		javaconfig.JavaTestMode,
@@ -161,6 +167,9 @@ func (jc *Configurer) Configure(c *config.Config, rel string, f *rule.File) {
 			case javaconfig.JavaMavenInstallFile:
 				cfg.SetMavenInstallFile(d.Value)
 
+			case javaconfig.JavaIndexFile:
+				cfg.SetMavenIndexFile(d.Value)
+
 			case javaconfig.JavaModuleGranularityDirective:
 				if err := cfg.SetModuleGranularity(d.Value); err != nil {
 					jc.lang.logger.Fatal().Err(err).Msgf("invalid value for directive %q", javaconfig.JavaModuleGranularityDirective)
@@ -260,6 +269,7 @@ func (jc *Configurer) Configure(c *config.Config, rel string, f *rule.File) {
 	if jc.lang.mavenResolver == nil {
 		resolver, err := maven.NewResolver(
 			cfg.MavenInstallFile(),
+			cfg.MavenIndexFile(),
 			jc.lang.logger,
 		)
 		if err != nil {

java/gazelle/javaconfig/config.go

@@ -26,6 +26,11 @@ const (
 	// Defaults to "maven_install.json".
 	JavaMavenInstallFile = "java_maven_install_file"
 
+	// JavaIndexFile represents the directive that controls where the index
+	// file generated by `rules_jvm_external` is located.
+	// Defaults to "maven_index.json"
+	JavaIndexFile = "java_index_file"
+
 	// JavaModuleGranularityDirective represents the directive that controls whether
 	// this Java module has a module granularity (Gradle) or a package
 	// granularity (bazel).
@@ -105,6 +110,7 @@ func (c *Config) NewChild() *Config {
 		resolveToJavaExports:   c.resolveToJavaExports,
 		kotlinEnabled:          c.kotlinEnabled,
 		mavenInstallFile:       c.mavenInstallFile,
+		javaIndexFile:          c.javaIndexFile,
 		moduleGranularity:      c.moduleGranularity,
 		repoRoot:               c.repoRoot,
 		testMode:               c.testMode,
@@ -138,6 +144,7 @@ type Config struct {
 	resolveToJavaExports                               *types.LateInit[bool]
 	kotlinEnabled                                      bool
 	mavenInstallFile                                   string
+	javaIndexFile                                      string
 	moduleGranularity                                  string
 	repoRoot                                           string
 	testMode                                           string
@@ -166,6 +173,7 @@ func New(repoRoot string) *Config {
 		resolveToJavaExports:   types.NewLateInit[bool](true),
 		kotlinEnabled:          true,
 		mavenInstallFile:       "maven_install.json",
+		javaIndexFile:          "maven_index.json",
 		moduleGranularity:      "package",
 		repoRoot:               repoRoot,
 		testMode:               "suite",
@@ -234,6 +242,14 @@ func (c *Config) SetMavenInstallFile(filename string) {
 	c.mavenInstallFile = filename
 }
 
+func (c Config) MavenIndexFile() string {
+	return filepath.Join(c.repoRoot, c.javaIndexFile)
+}
+
+func (c *Config) SetMavenIndexFile(filename string) {
+	c.javaIndexFile = filename
+}
+
 func (c Config) ModuleGranularity() string {
 	return c.moduleGranularity
 }

java/gazelle/private/maven/config.go

@@ -103,6 +103,23 @@ type lockFileV2_Artifact struct {
 	Version string            `json:"version"`
 }
 
+type IndexFile struct {
+	Version int                            `json:"version"`
+	Classes map[string]map[string][]string `json:"classes"`
+}
+
+func loadIndex(filename string) (*IndexFile, error) {
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	var index IndexFile
+	if err := json.Unmarshal(data, &index); err != nil {
+		return nil, err
+	}
+	return &index, nil
+}
+
 func loadConfiguration(filename string) (lockFile, error) {
 	data, err := os.ReadFile(filename)
 	if err != nil {

java/gazelle/private/maven/resolver.go

@@ -2,6 +2,7 @@ package maven
 
 import (
 	"fmt"
+	"os"
 	"sort"
 
 	"github.com/bazel-contrib/rules_jvm/java/gazelle/private/bazel"
@@ -43,7 +44,7 @@ type resolver struct {
 	logger     zerolog.Logger
 }
 
-func NewResolver(installFile string, logger zerolog.Logger) (Resolver, error) {
+func NewResolver(installFile string, indexFile string, logger zerolog.Logger) (Resolver, error) {
 	r := resolver{
 		data:       multiset.NewStringMultiSet(),
 		classIndex: make(map[string]string),
@@ -56,6 +57,17 @@ func NewResolver(installFile string, logger zerolog.Logger) (Resolver, error) {
 		return &r, nil
 	}
 
+	var index *IndexFile
+	if indexFile != "" {
+		var err error
+		index, err = loadIndex(indexFile)
+		if err != nil {
+			if !os.IsNotExist(err) {
+				r.logger.Warn().Err(err).Msg("failed to load index file")
+			}
+		}
+	}
+
 	dependencies := c.ListDependencies()
 
 	r.logger.Debug().Int("count", len(dependencies)).Msg("Dependency count")
@@ -71,6 +83,19 @@ func NewResolver(installFile string, logger zerolog.Logger) (Resolver, error) {
 		for _, class := range c.ListDependencyClasses(depName) {
 			r.classIndex[class] = coords.ArtifactString()
 		}
+		if index != nil {
+			if pkgMap, ok := index.Classes[depName]; ok {
+				for pkg, classes := range pkgMap {
+					for _, cls := range classes {
+						fqcn := cls
+						if pkg != "" {
+							fqcn = pkg + "." + cls
+						}
+						r.classIndex[fqcn] = coords.ArtifactString()
+					}
+				}
+			}
+		}
 	}
 
 	return &r, nil

java/gazelle/private/maven/resolver_test.go

@@ -18,7 +18,7 @@ func TestResolver(t *testing.T) {
 
 	m := make(map[string]struct{})
 	m["@maven//:com_google_j2objc_j2objc_annotations"] = struct{}{}
-	r, err := NewResolver("testdata/guava_maven_install.json", logger)
+	r, err := NewResolver("testdata/guava_maven_install.json", "", logger)
 	if err != nil {
 		t.Fatal(err)
 	}

java/gazelle/testdata/class_index/WORKSPACE

@@ -0,0 +1 @@
+

java/gazelle/testdata/class_index/maven_index.json

@@ -0,0 +1,15 @@
+{
+  "version": 2,
+  "classes": {
+    "com.example:lib-a": {
+      "com.example.split": [
+        "ClassA"
+      ]
+    },
+    "com.example:lib-b": {
+      "com.example.split": [
+        "ClassB"
+      ]
+    }
+  }
+}

java/gazelle/testdata/class_index/maven_install.json

@@ -0,0 +1,11 @@
+{
+  "version": "2",
+  "artifacts": {
+    "com.example:lib-a": {
+      "version": "1.0"
+    },
+    "com.example:lib-b": {
+      "version": "1.0"
+    }
+  }
+}

java/gazelle/testdata/class_index/src/main/java/com/example/app/BUILD.in

@@ -0,0 +1 @@
+

java/gazelle/testdata/class_index/src/main/java/com/example/app/BUILD.out

@@ -0,0 +1,11 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
+java_library(
+    name = "app",
+    srcs = ["Main.java"],
+    visibility = ["//:__subpackages__"],
+    deps = [
+        "@maven//:com_example_lib_a",
+        "@maven//:com_example_lib_b",
+    ],
+)