Use shared mappings from 'java-module-dependencies' for 'known modules'

Author: jjohannes

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Extra Java Module Info Gradle Plugin - Changelog
 
+## Version 1.6.2
+* [New] - Use shared mappings from 'java-module-dependencies' for 'known modules' (if available)
+
 ## Version 1.6.1
 * [Fixed] [#89](https://github.com/gradlex-org/extra-java-module-info/issues/89) - Make Jar patching reproducible
 

src/main/java/org/gradlex/javamodule/moduleinfo/ExtraJavaModuleInfoTransform.java

@@ -494,13 +494,31 @@ private byte[] readAllBytes(InputStream inputStream) throws IOException {
 
     private String gaToModuleName(String ga) {
         ModuleSpec moduleSpec = getParameters().getModuleSpecs().get().get(ga);
-        if (moduleSpec == null) {
-            throw new RuntimeException("[requires directives from metadata] " +
-                    "The module name of the following component is not known: " + ga +
-                    "\n - If it is already a module, make the module name known using 'knownModule(\"" + ga + "\", \"<module name>\")'" +
-                    "\n - If it is not a module, patch it using 'module()' or 'automaticModule()'");
+        if (moduleSpec != null) {
+            return moduleSpec.getModuleName();
         }
-        return moduleSpec.getModuleName();
+        String moduleNameFromSharedMapping = moduleNameFromSharedMapping(ga);
+        if (moduleNameFromSharedMapping != null) {
+            return moduleNameFromSharedMapping;
+        }
+
+        throw new RuntimeException("[requires directives from metadata] " +
+                "The module name of the following component is not known: " + ga +
+                "\n - If it is already a module, make the module name known using 'knownModule(\"" + ga + "\", \"<module name>\")'" +
+                "\n - If it is not a module, patch it using 'module()' or 'automaticModule()'");
+    }
+
+    @Nullable
+    private String moduleNameFromSharedMapping(String ga) {
+        try {
+            Class<?> sharedMappings = Class.forName("org.gradlex.javamodule.dependencies.SharedMappings");
+            @SuppressWarnings("unchecked")
+            Map<String, String> mappings = (Map<String, String>) sharedMappings.getDeclaredField("mappings").get(null);
+            Optional<String> found = mappings.entrySet().stream().filter(
+                    e -> e.getValue().equals(ga)).map(Map.Entry::getKey).findFirst();
+            return found.orElse(null);
+        } catch (ReflectiveOperationException ignored) { }
+        return null;
     }
 
     private static boolean isModuleInfoClass(String jarEntryName) {