feat(internal/config): support libraries bom version and default java module (#4838)

Support for specifying a libraries_bom_version in the Java
configuration. It adds a default java module to the Default
configuration struct to allow shared Java settings across all libraries.
Updated the Java migration tool (tool/cmd/migrate/java.go) to parse
libraries_bom_version from generation_config.yaml and include it in the
generated librarian.yaml.

This version info is needed in README.md generation.

For #4306 
For #4308

Author: zhumin8

doc/config-schema.md

@@ -61,6 +61,7 @@ This document describes the schema for the librarian.yaml.
 | `tag_format` | string | Is the template for git tags, such as "{name}/v{version}". |
 | `dotnet` | [DotnetPackage](#dotnetpackage-configuration) (optional) | Contains .NET-specific default configuration. |
 | `dart` | [DartPackage](#dartpackage-configuration) (optional) | Contains Dart-specific default configuration. |
+| `java` | [JavaModule](#javamodule-configuration) (optional) | Contains Java-specific default configuration. |
 | `nodejs` | [NodejsPackage](#nodejspackage-configuration) (optional) | Contains Node.js-specific default configuration. |
 | `rust` | [RustDefault](#rustdefault-configuration) (optional) | Contains Rust-specific default configuration. |
 | `python` | [PythonDefault](#pythondefault-configuration) (optional) | Contains Python-specific default configuration. |
@@ -225,6 +226,7 @@ This document describes the schema for the librarian.yaml.
 | `extra_versioned_modules` | string | Is a list of extra versioned modules. |
 | `group_id` | string | Is the Maven group ID, defaults to "com.google.cloud". |
 | `issue_tracker_override` | string | Allows the "issue_tracker" field in .repo-metadata.json to be overridden. |
+| `libraries_bom_version` | string | Is the version of the libraries-bom to use for Java. |
 | `library_type_override` | string | Allows the "library_type" field in .repo-metadata.json to be overridden. |
 | `min_java_version` | int | Is the minimum Java version required. |
 | `name_pretty_override` | string | Allows the "name_pretty" field in .repo-metadata.json to be overridden. |

internal/config/config.go

@@ -142,6 +142,9 @@ type Default struct {
 	// Dart contains Dart-specific default configuration.
 	Dart *DartPackage `yaml:"dart,omitempty"`
 
+	// Java contains Java-specific default configuration.
+	Java *JavaModule `yaml:"java,omitempty"`
+
 	// Nodejs contains Node.js-specific default configuration.
 	Nodejs *NodejsPackage `yaml:"nodejs,omitempty"`
 

internal/config/language.go

@@ -522,6 +522,9 @@ type JavaModule struct {
 	// to be overridden.
 	IssueTrackerOverride string `yaml:"issue_tracker_override,omitempty"`
 
+	// LibrariesBomVersion is the version of the libraries-bom to use for Java.
+	LibrariesBomVersion string `yaml:"libraries_bom_version,omitempty"`
+
 	// LibraryTypeOverride allows the "library_type" field in .repo-metadata.json
 	// to be overridden.
 	LibraryTypeOverride string `yaml:"library_type_override,omitempty"`

tool/cmd/migrate/java.go

@@ -123,6 +123,7 @@ type LibraryConfig struct {
 // GenerationConfig represents the root of generation_config.yaml.
 type GenerationConfig struct {
 	GoogleapisCommitish string          `yaml:"googleapis_commitish"`
+	LibrariesBomVersion string          `yaml:"libraries_bom_version"`
 	Libraries           []LibraryConfig `yaml:"libraries"`
 }
 
@@ -260,6 +261,11 @@ func buildConfig(gen *GenerationConfig, repoPath string, src *config.Source, ver
 	}
 	return &config.Config{
 		Language: "java",
+		Default: &config.Default{
+			Java: &config.JavaModule{
+				LibrariesBomVersion: gen.LibrariesBomVersion,
+			},
+		},
 		Sources: &config.Sources{
 			Googleapis: src,
 		},

tool/cmd/migrate/java_test.go

@@ -91,7 +91,9 @@ func TestBuildConfig(t *testing.T) {
 			want: &config.Config{
 				Language: "java",
 				Repo:     "googleapis/google-cloud-java",
-
+				Default: &config.Default{
+					Java: &config.JavaModule{},
+				},
 				Sources: &config.Sources{
 					Googleapis: &config.Source{Dir: "../../internal/testdata/googleapis"},
 				},
@@ -121,7 +123,9 @@ func TestBuildConfig(t *testing.T) {
 			want: &config.Config{
 				Language: "java",
 				Repo:     "googleapis/google-cloud-java",
-
+				Default: &config.Default{
+					Java: &config.JavaModule{},
+				},
 				Sources: &config.Sources{
 					Googleapis: &config.Source{Dir: "../../internal/testdata/googleapis"},
 				},
@@ -157,7 +161,9 @@ func TestBuildConfig(t *testing.T) {
 			want: &config.Config{
 				Language: "java",
 				Repo:     "googleapis/google-cloud-java",
-
+				Default: &config.Default{
+					Java: &config.JavaModule{},
+				},
 				Sources: &config.Sources{
 					Googleapis: &config.Source{Dir: "../../internal/testdata/googleapis"},
 				},
@@ -182,6 +188,7 @@ func TestBuildConfig(t *testing.T) {
 		{
 			name: "all java fields and overrides",
 			gen: &GenerationConfig{
+				LibrariesBomVersion: "1.2.3",
 				Libraries: []LibraryConfig{
 					{
 						LibraryName:           "pubsub",
@@ -217,7 +224,11 @@ func TestBuildConfig(t *testing.T) {
 			want: &config.Config{
 				Language: "java",
 				Repo:     "googleapis/google-cloud-java",
-
+				Default: &config.Default{
+					Java: &config.JavaModule{
+						LibrariesBomVersion: "1.2.3",
+					},
+				},
 				Sources: &config.Sources{
 					Googleapis: &config.Source{Dir: "../../internal/testdata/googleapis"},
 				},
@@ -280,7 +291,9 @@ func TestBuildConfig(t *testing.T) {
 			want: &config.Config{
 				Language: "java",
 				Repo:     "googleapis/google-cloud-java",
-
+				Default: &config.Default{
+					Java: &config.JavaModule{},
+				},
 				Sources: &config.Sources{
 					Googleapis: &config.Source{Dir: "../../internal/testdata/googleapis"},
 				},