Fixes

Author: liach

make/jdk/src/classes/build/tools/taglet/SealedGraph.java

@@ -298,7 +298,7 @@ private String simpleName(String name) {
 
         private static List<TypeElement> permittedSubclasses(TypeElement node, Set<String> exports) {
             List<TypeElement> dfsStack = new ArrayList<TypeElement>().reversed(); // Faster operations to head
-            List<TypeElement> result = new ArrayList<>();
+            SequencedCollection<TypeElement> result = new LinkedHashSet<>(); // Deduplicate diamond interface inheritance
             // The starting node may be in the public API - still expand it
             prependSubclasses(node, dfsStack);
 

test/langtools/jdk/javadoc/taglet/sealedGraph/TestSealedTaglet.java

@@ -29,7 +29,7 @@
  * @modules jdk.compiler/com.sun.tools.javac.api
  *          jdk.compiler/com.sun.tools.javac.main
  *          jdk.javadoc/jdk.javadoc.internal.tool
- * @build javadoc.tester.* toolbox.ToolBox builder.ClassBuilder
+ * @build javadoc.tester.* toolbox.ToolBox builder.ClassBuilder JdkTaglets
  * @run main ${test.main.class}
  */
 
@@ -67,16 +67,23 @@ public void testInvisibleInMiddle(Path base) throws Exception {
                 }
                 """);
         new ClassBuilder(tb, "pkg.A")
-                .setModifiers("public", "abstract", "sealed", "class")
+                .setModifiers("public", "abstract", "sealed", "interface")
                 .setComments("@sealedGraph")
                 .addPermits("pkg.B")
                 .write(srcDir);
         new ClassBuilder(tb, "pkg.B")
-                .setModifiers("abstract", "sealed", "class")
-                .addPermits("pkg.C")
+                .setModifiers("abstract", "sealed", "interface")
+                .addImplements("pkg.A")
+                .addPermits("pkg.C", "pkg.D")
                 .write(srcDir);
         new ClassBuilder(tb, "pkg.C")
+                .setModifiers("abstract", "sealed", "interface")
+                .addImplements("pkg.A", "pkg.B")
+                .addPermits("pkg.D")
+                .write(srcDir);
+        new ClassBuilder(tb, "pkg.D")
                 .setModifiers("public", "final", "class")
+                .addImplements("pkg.B", "pkg.C")
                 .write(srcDir);
 
         System.setProperty("sealedDotOutputDir", outDir.toString());
@@ -88,7 +95,7 @@ public void testInvisibleInMiddle(Path base) throws Exception {
                 "pkg");
 
         checkExit(Exit.OK);
-        // C is displayed as a direct subtype of A, bypassing B
-        checkOutput("test_pkg.A.dot", true, "\"pkg.C\" -> \"pkg.A\";");
+        // D is displayed as a direct subtype of A, bypassing B, C, one link only
+        checkUnique("test_pkg.A.dot", "\"pkg.D\" -> \"pkg.A\";");
     }
 }

test/langtools/tools/lib/builder/ClassBuilder.java

@@ -238,25 +238,26 @@ public String toString() {
                 ow.println("// NO_API_COMMENT");
                 break;
         }
+        assert !modifiers.modifiers.isEmpty();
         ow.print(modifiers.toString());
         ow.print(clsname);
         if (typeParameter != null) {
-            ow.print(typeParameter + " ");
-        } else {
-            ow.print(" ");
+            ow.print(typeParameter);
         }
         if (extendsType != null && !extendsType.isEmpty()) {
-            ow.print("extends " + extendsType + " ");
+            var last = modifiers.modifiers.getLast();
+            assert !last.equals("interface") && !last.equals("@interface");
+            ow.print(" extends " + extendsType);
         }
         if (!implementsTypes.isEmpty()) {
-            ow.print("implements ");
+            ow.print(modifiers.modifiers.getLast().equals("interface") ? " extends " : " implements ");
             ow.print(String.join(", ", implementsTypes));
         }
         if (!permitsTypes.isEmpty()) {
-            ow.print("permits ");
+            ow.print(" permits ");
             ow.print(String.join(", ", permitsTypes));
         }
-        ow.print("{");
+        ow.print(" {");
         if (!nested.isEmpty()) {
             ow.println("");
             nested.forEach(m -> ow.println(m.toString()));