Wrap native JS exceptions as java.lang.RuntimeException

core/src/main/java/org/teavm/backend/javascript/JavaScriptTarget.java

@@ -251,6 +251,12 @@ public class JavaScriptTarget implements TeaVMTarget, TeaVMJavaScriptHost {
         exceptionCons.use();
         exceptionCons.getVariable(0).propagate(dependencyAnalyzer.getType(NoSuchMethodError.class.getName()));
         exceptionCons.getVariable(1).propagate(dependencyAnalyzer.getType("java.lang.String"));
+
+        exceptionCons = dependencyAnalyzer.linkMethod(new MethodReference(
+                RuntimeException.class, "<init>", String.class, void.class), null);
+        exceptionCons.getVariable(0).propagate(dependencyAnalyzer.getType(RuntimeException.class.getName()));
+        exceptionCons.getVariable(1).propagate(dependencyAnalyzer.getType("java.lang.String"));
+        exceptionCons.use();
     }
 
     @Override

core/src/main/java/org/teavm/backend/javascript/rendering/RuntimeRenderer.java

@@ -50,6 +50,7 @@ public class RuntimeRenderer {
             renderRuntimeNullCheck();
             renderRuntimeIntern();
             renderRuntimeThreads();
+            renderRuntimeCreateException();
         } catch (NamingException e) {
             throw new RenderingException("Error rendering runtime methods. See a cause for details", e);
         } catch (IOException e) {
@@ -160,4 +161,13 @@ public class RuntimeRenderer {
                 .append("(t);").softNewLine();
         writer.outdent().append("}").newLine();
     }
+
+    private void renderRuntimeCreateException() throws IOException {
+        writer.append("function $rt_createException(message)").ws().append("{").indent().softNewLine();
+        writer.append("return ");
+        writer.append(writer.getNaming().getNameForInit(new MethodReference(RuntimeException.class,
+                "<init>", String.class, void.class)));
+        writer.append("(message);").softNewLine();
+        writer.outdent().append("}").newLine();
+    }
 }

core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java

@@ -1400,24 +1400,46 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
             visitStatements(protectedBody);
             writer.outdent().append("}").ws().append("catch").ws().append("($$e)")
                     .ws().append("{").indent().softNewLine();
-            writer.append("$$je").ws().append("=").ws().append("$$e.$javaException;").softNewLine();
+            writer.append("$$je").ws().append("=").ws().append("$rt_wrapException($$e);").softNewLine();
+            boolean first = true;
+            boolean defaultHandlerOccurred = false;
             for (TryCatchStatement catchClause : sequence) {
-                writer.append("if").ws().append("($$je");
+                if (!first) {
-                if (catchClause.getExceptionType() != null) {
+                    writer.ws().append("else");
-                    writer.ws().append("&&").ws().append("$$je instanceof ")
-                            .appendClass(catchClause.getExceptionType());
                 }
-                writer.append(")").ws().append("{").indent().softNewLine();
+                if (catchClause.getExceptionType() != null) {
+                    if (!first) {
+                        writer.append(" ");
+                    }
+                    writer.append("if").ws().append("($$je instanceof ").appendClass(catchClause.getExceptionType());
+                    writer.append(")").ws();
+                } else {
+                    defaultHandlerOccurred = true;
+                }
+
+                if (catchClause.getExceptionType() != null || !first) {
+                    writer.append("{").indent().softNewLine();
+                }
+
                 if (catchClause.getExceptionVariable() != null) {
                     writer.append(variableName(catchClause.getExceptionVariable())).ws().append("=").ws()
                             .append("$$je;").softNewLine();
                 }
                 visitStatements(catchClause.getHandler());
-                writer.outdent().append("}").ws().append("else ");
+
+                if (catchClause.getExceptionType() != null || !first) {
+                    writer.outdent().append("}");
+                }
+
+                first = false;
+            }
+            if (!defaultHandlerOccurred) {
+                writer.ws().append("else").ws().append("{").indent().softNewLine();
+                writer.append("throw $$je;").softNewLine();
+                writer.outdent().append("}").softNewLine();
+            } else {
+                writer.softNewLine();
             }
-            writer.append("{").indent().softNewLine();
-            writer.append("throw $$e;").softNewLine();
-            writer.outdent().append("}").softNewLine();
             writer.outdent().append("}").softNewLine();
         } catch (IOException e) {
             throw new RenderingException("IO error occurred", e);

core/src/main/resources/org/teavm/backend/javascript/runtime.js

@@ -614,10 +614,18 @@ function $rt_intBitsToFloat(n) {
 function $rt_javaException(e) {
     return e instanceof Error && typeof e.$javaException === 'object' ? e.$javaException : null;
 }
-
 function $rt_jsException(e) {
     return typeof e.$jsException === 'object' ? e.$jsException : null;
 }
+function $rt_wrapException(err) {
+    var ex = err.$javaException;
+    if (!ex) {
+        ex = $rt_createException($rt_str("(JavaScript) " + err.toString()));
+        err.$javaException = ex;
+        ex.$jsException = err;
+    }
+    return ex;
+}
 
 function $dbg_class(obj) {
     var cls = obj.constructor;

tests/src/test/java/org/teavm/jso/test/ExceptionsTest.java

@@ -96,6 +96,18 @@ public class ExceptionsTest {
         assertEquals("foobar", sb.toString());
     }
 
+    @Test
+    public void catchNativeExceptionAsRuntimeException() {
+        StringBuilder sb = new StringBuilder();
+        try {
+            throwNativeException();
+        } catch (RuntimeException e) {
+            sb.append(e.getMessage());
+        }
+
+        assertEquals("(JavaScript) Error: foo", sb.toString());
+    }
+
     @JSBody(params = "runnable", script = "runnable();")
     private static native void runJsCode(JSRunnable runnable);