Add --incompatible_java_info_merge_runtime_module_flags

src/main/java/com/google/devtools/build/lib/packages/semantics/BuildLanguageOptions.java

@@ -573,6 +573,17 @@ public final class BuildLanguageOptions extends OptionsBase {
               + "host_javabase in compile will all be removed.")
   public boolean incompatibleJavaCommonParameters;
 
+  @Option(
+      name = "incompatible_java_info_merge_runtime_module_flags",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags = {OptionEffectTag.UNKNOWN},
+      metadataTags = {OptionMetadataTag.INCOMPATIBLE_CHANGE},
+      help =
+	  "If set to true, the JavaInfo constructor will merge add_exports and "
+	      + "add_opens of runtime_deps in addition to deps and exports.")
+  public boolean incompatibleJavaInfoMergeRuntimeModuleFlags;
+
   @Option(
       name = "max_computation_steps",
       defaultValue = "0",
@@ -743,6 +754,7 @@ public StarlarkSemantics toStarlarkSemantics() {
                 INCOMPATIBLE_FIX_PACKAGE_GROUP_REPOROOT_SYNTAX,
                 incompatibleFixPackageGroupReporootSyntax)
             .setBool(INCOMPATIBLE_JAVA_COMMON_PARAMETERS, incompatibleJavaCommonParameters)
+            .setBool(INCOMPATIBLE_JAVA_INFO_MERGE_RUNTIME_MODULE_FLAGS, incompatibleJavaInfoMergeRuntimeModuleFlags)
             .setBool(INCOMPATIBLE_NO_ATTR_LICENSE, incompatibleNoAttrLicense)
             .setBool(INCOMPATIBLE_NO_IMPLICIT_FILE_EXPORT, incompatibleNoImplicitFileExport)
             .setBool(INCOMPATIBLE_NO_PACKAGE_DISTRIBS, incompatibleNoPackageDistribs)
@@ -849,6 +861,8 @@ public StarlarkSemantics toStarlarkSemantics() {
       "+incompatible_do_not_split_linking_cmdline";
   public static final String INCOMPATIBLE_JAVA_COMMON_PARAMETERS =
       "+incompatible_java_common_parameters";
+  public static final String INCOMPATIBLE_JAVA_INFO_MERGE_RUNTIME_MODULE_FLAGS =
+      "-incompatible_java_info_merge_runtime_module_flags";
   public static final String INCOMPATIBLE_NO_ATTR_LICENSE = "+incompatible_no_attr_license";
   public static final String INCOMPATIBLE_NO_PACKAGE_DISTRIBS = "-incompatible_no_package_distribs";
   public static final String INCOMPATIBLE_NO_IMPLICIT_FILE_EXPORT =

src/main/java/com/google/devtools/build/lib/rules/java/JavaStarlarkCommon.java

@@ -397,6 +397,15 @@ public boolean isDepsetForJavaOutputSourceJarsEnabled(StarlarkThread thread)
         .getBool(BuildLanguageOptions.INCOMPATIBLE_DEPSET_FOR_JAVA_OUTPUT_SOURCE_JARS);
   }
 
+  @Override
+  public boolean isJavaInfoMergeRuntimeModuleFlagsEnabled(StarlarkThread thread)
+      throws EvalException {
+    checkPrivateAccess(thread);
+    return thread
+        .getSemantics()
+        .getBool(BuildLanguageOptions.INCOMPATIBLE_JAVA_INFO_MERGE_RUNTIME_MODULE_FLAGS);
+  }
+
   @Override
   public JavaInfo wrapJavaInfo(Info javaInfo, StarlarkThread thread)
       throws EvalException, RuleErrorException {

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/java/JavaCommonApi.java

@@ -691,6 +691,12 @@ void checkJavaToolchainIsDeclaredOnRuleForStarlark(
       useStarlarkThread = true)
   boolean isDepsetForJavaOutputSourceJarsEnabled(StarlarkThread thread) throws EvalException;
 
+  @StarlarkMethod(
+      name = "_incompatible_java_info_merge_runtime_module_flags",
+      documented = false,
+      useStarlarkThread = true)
+  boolean isJavaInfoMergeRuntimeModuleFlagsEnabled(StarlarkThread thread) throws EvalException;
+
   @StarlarkMethod(
       name = "wrap_java_info",
       parameters = {@Param(name = "java_info")},

src/main/starlark/builtins_bzl/common/java/java_info.bzl

@@ -723,6 +723,17 @@ def _javainfo_init(
             direct = [output_jar],
             transitive = [dep.transitive_runtime_jars for dep in concatenated_deps.exports_deps + runtime_deps],
         )
+
+    # For backward compatibility, we use deps_exports for add_exports/add_opens for JavaInfo constructor
+    # rather than runtimedeps_exports_deps (used by java_info_for_compilation).
+    # However, runtimedeps_exports_deps makes more sense.
+    #
+    # TODO: When this flag is removed, move this logic into _javainfo_init_base
+    #  and remove the special case from java_info_for_compilation.
+    module_flags_deps = concatenated_deps.deps_exports
+    if _java_common_internal._incompatible_java_info_merge_runtime_module_flags():
+        module_flags_deps = concatenated_deps.runtimedeps_exports_deps
+
     result.update(
         transitive_runtime_jars = transitive_runtime_jars,
         transitive_source_jars = depset(
@@ -736,11 +747,11 @@ def _javainfo_init(
         module_flags_info = _create_module_flags_info(
             add_exports = depset(transitive = [
                 dep.module_flags_info.add_exports
-                for dep in concatenated_deps.deps_exports
+                for dep in module_flags_deps
             ]),
             add_opens = depset(transitive = [
                 dep.module_flags_info.add_opens
-                for dep in concatenated_deps.deps_exports
+                for dep in module_flags_deps
             ]),
         ),
     )

src/test/java/com/google/devtools/build/lib/rules/java/JavaInfoStarlarkApiTest.java

@@ -850,18 +850,32 @@ public void buildHelperCreateJavaInfoWithManifestProto_javaRuleOutputJarsProvide
 
   @Test
   public void buildHelperCreateJavaInfoWithModuleFlags() throws Exception {
+    setBuildLanguageOptions("--noincompatible_java_info_merge_runtime_module_flags");
     ruleBuilder().build();
     scratch.file(
         "foo/BUILD",
         "load(':extension.bzl', 'my_rule')",
         "java_library(",
         "    name = 'my_java_lib_direct',",
         "    srcs = ['java/A.java'],",
+        "    add_exports = ['java.base/java.lang'],",
         "    add_opens = ['java.base/java.lang'],",
         ")",
+        "java_library(",
+        "    name = 'my_java_lib_runtime',",
+        "    srcs = ['java/A.java'],",
+        "    add_opens = ['java.base/java.util'],",
+        ")",
+        "java_library(",
+        "    name = 'my_java_lib_exports',",
+        "    srcs = ['java/A.java'],",
+        "    add_opens = ['java.base/java.math'],",
+        ")",
         "my_rule(",
         "    name = 'my_starlark_rule',",
         "    dep = [':my_java_lib_direct'],",
+        "    dep_runtime = [':my_java_lib_runtime'],",
+        "    dep_exports = [':my_java_lib_exports'],",
         "    output_jar = 'my_starlark_rule_lib.jar',",
         ")");
     assertNoEvents();
@@ -870,7 +884,56 @@ public void buildHelperCreateJavaInfoWithModuleFlags() throws Exception {
         fetchJavaInfo().getProvider(JavaModuleFlagsProvider.class);
 
     assertThat(ruleOutputs.toFlags())
-        .containsExactly("--add-opens=java.base/java.lang=ALL-UNNAMED");
+        .containsExactly(
+            "--add-exports=java.base/java.lang=ALL-UNNAMED",
+            // no java.base/java.util under --noincompatible_java_info_merge_runtime_module_flags
+            "--add-opens=java.base/java.lang=ALL-UNNAMED",
+            "--add-opens=java.base/java.math=ALL-UNNAMED")
+        .inOrder();
+  }
+
+  @Test
+  public void buildHelperCreateJavaInfoWithModuleFlagsIncompatibleMergeRuntime() throws Exception {
+    setBuildLanguageOptions("--incompatible_java_info_merge_runtime_module_flags");
+    ruleBuilder().build();
+    scratch.file(
+        "foo/BUILD",
+        "load(':extension.bzl', 'my_rule')",
+        "java_library(",
+        "    name = 'my_java_lib_direct',",
+        "    srcs = ['java/A.java'],",
+        "    add_exports = ['java.base/java.lang'],",
+        "    add_opens = ['java.base/java.lang'],",
+        ")",
+        "java_library(",
+        "    name = 'my_java_lib_runtime',",
+        "    srcs = ['java/A.java'],",
+        "    add_opens = ['java.base/java.util'],",
+        ")",
+        "java_library(",
+        "    name = 'my_java_lib_exports',",
+        "    srcs = ['java/A.java'],",
+        "    add_opens = ['java.base/java.math'],",
+        ")",
+        "my_rule(",
+        "    name = 'my_starlark_rule',",
+        "    dep = [':my_java_lib_direct'],",
+        "    dep_runtime = [':my_java_lib_runtime'],",
+        "    dep_exports = [':my_java_lib_exports'],",
+        "    output_jar = 'my_starlark_rule_lib.jar',",
+        ")");
+    assertNoEvents();
+
+    JavaModuleFlagsProvider ruleOutputs =
+        fetchJavaInfo().getProvider(JavaModuleFlagsProvider.class);
+
+    assertThat(ruleOutputs.toFlags())
+        .containsExactly(
+            "--add-exports=java.base/java.lang=ALL-UNNAMED",
+            "--add-opens=java.base/java.util=ALL-UNNAMED",
+            "--add-opens=java.base/java.math=ALL-UNNAMED",
+            "--add-opens=java.base/java.lang=ALL-UNNAMED")
+        .inOrder();
   }
 
   @Test