From f6103ec00bd05b9f43c00e45c6f6b7fbcc95b493 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Sat, 28 Jan 2017 22:39:44 +0300
Subject: [PATCH] Copy exception variables when splitting async programs. Fix
 https://github.com/konsoletyper/teavm/issues/230

---
 .../teavm/model/util/AsyncProgramSplitter.java   |  9 +++++++++
 tests/src/test/java/org/teavm/vm/VMTest.java     | 16 ++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java b/core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
index dfcd9af61..9b2780fa7 100644
--- a/core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
+++ b/core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
@@ -95,6 +95,10 @@ public class AsyncProgramSplitter {
 
                 // If we met asynchronous invocation...
                 // Copy portion of current block from last occurrence (or from start) to i'th instruction.
+                if (sourceBlock.getExceptionVariable() != null) {
+                    targetBlock.setExceptionVariable(targetBlock.getProgram().variableAt(
+                            sourceBlock.getExceptionVariable().getIndex()));
+                }
                 targetBlock.addAll(ProgramUtils.copyInstructions(last, insn, targetBlock.getProgram()));
                 targetBlock.getTryCatchBlocks().addAll(ProgramUtils.copyTryCatches(sourceBlock,
                         targetBlock.getProgram()));
@@ -140,6 +144,11 @@ public class AsyncProgramSplitter {
                 step.targetPart = part;
                 part.originalBlocks[targetBlock.getIndex()] = step.source;
             }
+
+            if (sourceBlock.getExceptionVariable() != null) {
+                targetBlock.setExceptionVariable(targetBlock.getProgram().variableAt(
+                        sourceBlock.getExceptionVariable().getIndex()));
+            }
             targetBlock.addAll(ProgramUtils.copyInstructions(last, null, targetBlock.getProgram()));
             targetBlock.getTryCatchBlocks().addAll(ProgramUtils.copyTryCatches(sourceBlock, targetBlock.getProgram()));
             targetBlock.setExceptionVariable(sourceBlock.getExceptionVariable());
diff --git a/tests/src/test/java/org/teavm/vm/VMTest.java b/tests/src/test/java/org/teavm/vm/VMTest.java
index 93f92ca2b..6a68de92c 100644
--- a/tests/src/test/java/org/teavm/vm/VMTest.java
+++ b/tests/src/test/java/org/teavm/vm/VMTest.java
@@ -165,12 +165,28 @@ public class VMTest {
         }
     }
 
+    @Test
+    @SkipJVM
+    public void asyncExceptionHandler() {
+        try {
+            throw new RuntimeException("OK");
+        } catch (RuntimeException e) {
+            assertEquals("OK", suspendAndReturn(e).getMessage());
+        }
+    }
+
     @Async
     private static native void throwExceptionAsync();
     private static void throwExceptionAsync(AsyncCallback<Void> callback) {
         callback.error(new RuntimeException("OK"));
     }
 
+    @Async
+    private static native <T> T suspendAndReturn(T value);
+    private static <T> void suspendAndReturn(T value, AsyncCallback<T> callback) {
+        callback.complete(value);
+    }
+
     @JSBody(script = "return [1, 2]")
     private static native int[] createArray();