Fix for IDEABKL-8006 IDE hangs when decompiling class which

is its own superclass

GitOrigin-RevId: 1fe14694ce69b135f2e3fe4cde84ce3d42997228

src/org/jetbrains/java/decompiler/main/collectors/ImportCollector.java

@@ -39,8 +39,10 @@ public class ImportCollector {
 
     Map<String, StructClass> classes = DecompilerContext.getStructContext().getClasses();
     LinkedList<String> queue = new LinkedList<>();
+    Set<StructClass> processedClasses = new HashSet<>();
     StructClass currentClass = root.classStruct;
     while (currentClass != null) {
+      processedClasses.add(currentClass);
       if (currentClass.superClass != null) {
         queue.add(currentClass.superClass.getString());
       }
@@ -63,10 +65,17 @@ public class ImportCollector {
       }
 
       // .. and traverse through parent.
-      currentClass = !queue.isEmpty() ? classes.get(queue.removeFirst()) : null;
-      while (currentClass == null && !queue.isEmpty()) {
-        currentClass = classes.get(queue.removeFirst());
-      }
+      do {
+        currentClass = queue.isEmpty() ? null : classes.get(queue.removeFirst());
+
+        if (currentClass != null && processedClasses.contains(currentClass)) {
+          // Class already processed, skipping.
+
+          // This may be sign of circularity in the class hierarchy but in most cases this mean that same interface
+          // are listed as implemented several times in the class hierarchy.
+          currentClass = null;
+        }
+      } while (currentClass == null && !queue.isEmpty());
     }
   }
 

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -5,7 +5,9 @@ import org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.Timeout;
 
 import java.io.File;
 import java.io.IOException;
@@ -19,6 +21,13 @@ import static org.junit.Assert.assertTrue;
 public class SingleClassesTest {
   private DecompilerTestFixture fixture;
 
+  /*
+   * Set individual test duration time limit to 60 seconds.
+   * This will help us to test bugs hanging decompiler.
+   */
+  @Rule
+  public Timeout globalTimeout = Timeout.seconds(60);
+
   @Before
   public void setUp() throws IOException {
     fixture = new DecompilerTestFixture();
@@ -135,6 +144,8 @@ public class SingleClassesTest {
   @Test public void testRecordGenericVararg() { doTest("records/TestRecordGenericVararg"); }
   @Test public void testRecordAnno() { doTest("records/TestRecordAnno"); }
 
+  @Test public void testInheritanceChainCycle() { doTest("pkg/TestInheritanceChainCycle"); }
+
   private void doTest(String testFile, String... companionFiles) {
     ConsoleDecompiler decompiler = fixture.getDecompiler();
 

testData/results/TestInheritanceChainCycle.dec

@@ -0,0 +1,22 @@
+package pkg;
+
+public class TestInheritanceChainCycle extends TestInheritanceChainCycle {
+   public void printMessage() {
+      System.out.println("Hello, bug!");// 21 22 23
+   }// 24
+}
+
+class 'pkg/TestInheritanceChainCycle' {
+   method 'printMessage ()V' {
+      0      4
+      3      4
+      5      4
+      8      5
+   }
+}
+
+Lines mapping:
+21 <-> 5
+22 <-> 5
+23 <-> 5
+24 <-> 6

testData/src/pkg/TestInheritanceChainCycle.jasm

@@ -0,0 +1,27 @@
+/**
+ * This code can be assembled with <a href="https://wiki.openjdk.java.net/display/CodeTools/asmtools">asmtools</a>
+ * using <code>asmtools jasm -g *.jasm</code> command line.
+ */
+package  pkg;
+
+super public class TestInheritanceChainCycle
+	extends TestInheritanceChainCycle
+	version 52:0
+{
+  public Method "<init>":"()V"
+	stack 1 locals 1
+  {
+		aload_0;
+		invokespecial	Method java/lang/Object."<init>":"()V";
+		return;
+  }
+  public Method printMessage:"()V"
+	stack 2 locals 1
+  {
+		getstatic	Field java/lang/System.out:"Ljava/io/PrintStream;";
+		ldc	String "Hello, bug!";
+		invokevirtual	Method java/io/PrintStream.println:"(Ljava/lang/String;)V";
+		return;
+  }
+
+} // end Class TestInheritanceChainCycle