fix: correct detection of exits in synchronized block (#942)

jadx-core/src/main/java/jadx/core/dex/regions/SynchronizedRegion.java

@@ -1,6 +1,6 @@
 package jadx.core.dex.regions;
 
-import java.util.LinkedList;
+import java.util.ArrayList;
 import java.util.List;
 
 import jadx.core.dex.nodes.IContainer;
@@ -10,7 +10,7 @@
 public final class SynchronizedRegion extends AbstractRegion {
 
 	private final InsnNode enterInsn;
-	private final List<InsnNode> exitInsns = new LinkedList<>();
+	private final List<InsnNode> exitInsns = new ArrayList<>();
 	private final Region region;
 
 	public SynchronizedRegion(IRegion parent, InsnNode insn) {

jadx-core/src/main/java/jadx/core/utils/BlockUtils.java

@@ -6,7 +6,6 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -538,17 +537,22 @@ private static void collectWhileDominates(BlockNode dominator, BlockNode child,
 	}
 
 	public static List<BlockNode> buildSimplePath(BlockNode block) {
-		List<BlockNode> list = new LinkedList<>();
-		BlockNode currentBlock = block;
+		if (block == null) {
+			return Collections.emptyList();
+		}
+		List<BlockNode> list = new ArrayList<>();
+		if (block.getCleanSuccessors().size() >= 2) {
+			return Collections.emptyList();
+		}
+		list.add(block);
+
+		BlockNode currentBlock = getNextBlock(block);
 		while (currentBlock != null
 				&& currentBlock.getCleanSuccessors().size() < 2
 				&& currentBlock.getPredecessors().size() == 1) {
 			list.add(currentBlock);
 			currentBlock = getNextBlock(currentBlock);
 		}
-		if (list.isEmpty()) {
-			return Collections.emptyList();
-		}
 		return list;
 	}
 

jadx-core/src/test/java/jadx/tests/integration/synchronize/TestSynchronized4.java

@@ -0,0 +1,31 @@
+package jadx.tests.integration.synchronize;
+
+import org.junit.jupiter.api.Test;
+
+import jadx.tests.api.SmaliTest;
+
+import static jadx.tests.api.utils.assertj.JadxAssertions.assertThat;
+
+public class TestSynchronized4 extends SmaliTest {
+
+	// @formatter:off
+	/*
+		public boolean test(int i) {
+			synchronized (this.obj) {
+				if (isZero(i)) {
+					return call(obj, i);
+				}
+				System.out.println();
+				return getField() == null;
+			}
+		}
+	*/
+	// @formatter:on
+
+	@Test
+	public void test() {
+		assertThat(getClassNodeFromSmali())
+				.code()
+				.containsOne("synchronized (this.obj) {");
+	}
+}

jadx-core/src/test/smali/synchronize/TestSynchronized4.smali

@@ -0,0 +1,105 @@
+.class public Lsynchronize/TestSynchronized4;
+.super Ljava/lang/Object;
+
+.field private final obj:Ljava/lang/Object;
+
+.method public constructor <init>()V
+    .registers 2
+
+    invoke-direct {p0}, Ljava/lang/Object;-><init>()V
+
+    new-instance v0, Ljava/lang/Object;
+
+    invoke-direct {v0}, Ljava/lang/Object;-><init>()V
+
+    iput-object v0, p0, Lsynchronize/TestSynchronized4;->obj:Ljava/lang/Object;
+
+    return-void
+.end method
+
+.method public test(I)Z
+    .registers 4
+
+    iget-object v1, p0, Lsynchronize/TestSynchronized4;->obj:Ljava/lang/Object;
+
+    monitor-enter v1
+
+    :try_start_3
+    invoke-direct {p0, p1}, Lsynchronize/TestSynchronized4;->isZero(I)Z
+    move-result v0
+
+    if-eqz v0, :cond_11
+
+    iget-object v0, p0, Lsynchronize/TestSynchronized4;->obj:Ljava/lang/Object;
+
+    invoke-direct {p0, v0, p1}, Lsynchronize/TestSynchronized4;->call(Ljava/lang/Object;I)Z
+    move-result v0
+
+    monitor-exit v1
+
+    :goto_10
+    return v0
+
+    :cond_11
+    sget-object v0, Ljava/lang/System;->out:Ljava/io/PrintStream;
+
+    invoke-virtual {v0}, Ljava/io/PrintStream;->println()V
+
+    invoke-direct {p0}, Lsynchronize/TestSynchronized4;->getField()Ljava/lang/Object;
+
+    move-result-object v0
+
+    if-nez v0, :cond_22
+
+    const/4 v0, 0x1
+
+    :goto_1d
+    monitor-exit v1
+    return v0
+
+    :catchall_1f
+    move-exception v0
+
+    monitor-exit v1
+    :try_end_21
+    .catchall {:try_start_3 .. :try_end_21} :catchall_1f
+
+    throw v0
+
+    :cond_22
+    const/4 v0, 0x0
+
+    goto :goto_1d
+.end method
+
+.method private call(Ljava/lang/Object;I)Z
+    .registers 4
+
+    const/4 v0, 0x0
+
+    return v0
+.end method
+
+.method private getField()Ljava/lang/Object;
+    .registers 2
+
+    const/4 v0, 0x0
+
+    return-object v0
+.end method
+
+.method private isZero(I)Z
+    .registers 3
+
+    if-nez p1, :cond_4
+
+    const/4 v0, 0x1
+
+    :goto_3
+    return v0
+
+    :cond_4
+    const/4 v0, 0x0
+
+    goto :goto_3
+.end method