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Merged
shai-almog merged 1 commit into from
May 12, 2026
Merged

playground: surface lambda runtime errors instead of swallowing them silently #4926

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51 changes: 48 additions & 3 deletions scripts/cn1playground/common/src/main/java/bsh/cn1/CN1LambdaSupport.java
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,15 @@
public final class CN1LambdaSupport {
private static final ThreadLocal<Interpreter> CURRENT_INTERPRETER = new ThreadLocal<Interpreter>();
private static final ThreadLocal<NameSpace> CURRENT_NAMESPACE = new ThreadLocal<NameSpace>();
private static final ThreadLocal<LambdaErrorHandler> CURRENT_ERROR_HANDLER = new ThreadLocal<LambdaErrorHandler>();

/** Callback invoked when a lambda body raises an exception during
* {@link LambdaValue#invoke(Object[])}. Lets a host (e.g. the
* playground UI) surface runtime failures that would otherwise be
* lost to the EDT's silent exception handling. */
public interface LambdaErrorHandler {
void onLambdaError(Throwable error, String bodySource);
}

private CN1LambdaSupport() {
}
Expand All @@ -33,14 +42,28 @@ public static void clearCurrentNameSpace() {
CURRENT_NAMESPACE.remove();
}

/** Register a {@link LambdaErrorHandler} that will be captured by any
* {@link LambdaValue} created on this thread while the handler is
* active. The captured handler stays with the lambda for its
* lifetime so errors raised on later EDT firings can still surface
* back to the host. */
public static void pushErrorHandler(LambdaErrorHandler handler) {
CURRENT_ERROR_HANDLER.set(handler);
}

public static void clearErrorHandler() {
CURRENT_ERROR_HANDLER.remove();
}

public static LambdaValue lambda(String[] parameterNames, String bodySource) {
Interpreter interpreter = CURRENT_INTERPRETER.get();
if (interpreter == null) {
throw new IllegalStateException("No active BeanShell interpreter available for lambda capture.");
}
NameSpace activeNs = CURRENT_NAMESPACE.get();
NameSpace parentNs = activeNs != null ? activeNs : interpreter.getNameSpace();
return new LambdaValue(interpreter, parentNs, sanitizeParams(parameterNames), bodySource == null ? "" : bodySource);
return new LambdaValue(interpreter, parentNs, sanitizeParams(parameterNames),
bodySource == null ? "" : bodySource, CURRENT_ERROR_HANDLER.get());
}

private static String[] sanitizeParams(String[] parameterNames) {
Expand Down Expand Up @@ -135,12 +158,15 @@ public static final class LambdaValue implements
private final NameSpace parentNameSpace;
private final String[] parameterNames;
private final String bodySource;
private final LambdaErrorHandler errorHandler;

LambdaValue(Interpreter interpreter, NameSpace parentNameSpace, String[] parameterNames, String bodySource) {
LambdaValue(Interpreter interpreter, NameSpace parentNameSpace, String[] parameterNames,
String bodySource, LambdaErrorHandler errorHandler) {
this.interpreter = interpreter;
this.parentNameSpace = parentNameSpace;
this.parameterNames = parameterNames;
this.bodySource = bodySource;
this.errorHandler = errorHandler;
}

/** Runnable adapter — zero-arg lambda. */
Expand Down Expand Up @@ -206,7 +232,9 @@ public Object invoke(Object[] args) throws EvalError {
lambdaNs.setVariable(parameterNames[i], safeArgs[i], false);
}
} catch (UtilEvalError ex) {
throw ex.toEvalError(null, null);
EvalError converted = ex.toEvalError(null, null);
reportError(converted);
throw converted;
}
Interpreter prevInterpreter = CURRENT_INTERPRETER.get();
NameSpace prevNamespace = CURRENT_NAMESPACE.get();
Expand All @@ -216,6 +244,12 @@ public Object invoke(Object[] args) throws EvalError {
synchronized (interpreter) {
return Primitive.unwrap(interpreter.eval(bodySource, lambdaNs));
}
} catch (EvalError ex) {
reportError(ex);
throw ex;
} catch (RuntimeException ex) {
reportError(ex);
throw ex;
} finally {
if (prevInterpreter != null) {
CURRENT_INTERPRETER.set(prevInterpreter);
Expand All @@ -229,6 +263,17 @@ public Object invoke(Object[] args) throws EvalError {
}
}
}

private void reportError(Throwable error) {
if (errorHandler == null) {
return;
}
try {
errorHandler.onLambdaError(error, bodySource);
} catch (Throwable ignored) {
// Reporter failures must not displace the real lambda error.
}
}
}

/** Adapt a {@link LambdaValue} to a {@link java.util.function.BinaryOperator}
Expand Down
17 changes: 10 additions & 7 deletions scripts/cn1playground/common/src/main/java/bsh/cn1/GeneratedCN1Access.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -726,6 +726,7 @@ public final class GeneratedCN1Access implements CN1Access {
"com.codenameone.playground.CN1Playground",
"com.codenameone.playground.PlaygroundContext",
"com.codenameone.playground.PlaygroundContext.Logger",
"com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter",
"com.codenameone.playground.PlaygroundLambdaBridge",
"com.codenameone.playground.PlaygroundListenerBridge",
"com.codenameone.playground.WebsiteThemeNative",
Expand Down Expand Up @@ -1599,19 +1600,20 @@ private static void fillMethodIndex9(Map<String, String[]> index) {
index.put("com.codename1.xml.XMLParser", splitMembers(""));
index.put("com.codename1.xml.XMLWriter", splitMembers(""));
index.put("com.codenameone.playground.CN1Playground", splitMembers("destroy()getTheme()init(Object)runApp()start()stop()"));
index.put("com.codenameone.playground.PlaygroundContext", splitMembers("captureShownForm(Form)clearCreatedComponents()clearPreview()clearShownForm()getCreatedComponents()getFirstCreatedComponent()getFirstCreatedForm()getHostForm()getPreviewRoot()getShownForm()getTheme()log(String)recordCreatedComponent(Component)refreshPreview()setTitle(String)debug(String)getCurrent()interceptMethodInvocation(Object, String, Object[])notifyConstructed(Object)"));
index.put("com.codenameone.playground.PlaygroundContext", splitMembers("captureShownForm(Form)clearCreatedComponents()clearPreview()clearShownForm()getCreatedComponents()getFirstCreatedComponent()getFirstCreatedForm()getHostForm()getPreviewRoot()getShownForm()getTheme()log(String)recordCreatedComponent(Component)refreshPreview()reportRuntimeError(String, Throwable)setTitle(String)debug(String)getCurrent()interceptMethodInvocation(Object, String, Object[])notifyConstructed(Object)"));
index.put("com.codenameone.playground.PlaygroundContext.Logger", splitMembers("log(String)"));
index.put("com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter", splitMembers("reportRuntimeError(String, Throwable)"));
index.put("com.codenameone.playground.PlaygroundLambdaBridge", splitMembers("lambda(Object[], String)lambda(String[], String)"));
index.put("com.codenameone.playground.PlaygroundListenerBridge", splitMembers("actionListener(Object)networkListener(Object)onComplete(Object)runnable(Object)"));
index.put("com.codenameone.playground.WebsiteThemeNative", splitMembers("isDarkMode()isSupported()notifyUiReady()"));
index.put("java.io.ByteArrayInputStream", splitMembers(""));
index.put("java.io.ByteArrayOutputStream", splitMembers(""));
index.put("java.io.DataInput", splitMembers(""));
index.put("java.io.DataInputStream", splitMembers(""));
index.put("java.io.DataOutput", splitMembers(""));
}

private static void fillMethodIndex10(Map<String, String[]> index) {
index.put("java.io.DataOutput", splitMembers(""));
index.put("java.io.DataOutputStream", splitMembers(""));
index.put("java.io.EOFException", splitMembers(""));
index.put("java.io.Flushable", splitMembers(""));
Expand Down Expand Up @@ -1675,10 +1677,10 @@ private static void fillMethodIndex10(Map<String, String[]> index) {
index.put("java.lang.OutOfMemoryError", splitMembers(""));
index.put("java.lang.Override", splitMembers(""));
index.put("java.lang.Runnable", splitMembers(""));
index.put("java.lang.Runtime", splitMembers(""));
}

private static void fillMethodIndex11(Map<String, String[]> index) {
index.put("java.lang.Runtime", splitMembers(""));
index.put("java.lang.RuntimeException", splitMembers(""));
index.put("java.lang.SafeVarargs", splitMembers(""));
index.put("java.lang.SecurityException", splitMembers(""));
Expand Down Expand Up @@ -1742,10 +1744,10 @@ private static void fillMethodIndex11(Map<String, String[]> index) {
index.put("java.util.Comparator", splitMembers(""));
index.put("java.util.ConcurrentModificationException", splitMembers(""));
index.put("java.util.Date", splitMembers(""));
index.put("java.util.Deque", splitMembers(""));
}

private static void fillMethodIndex12(Map<String, String[]> index) {
index.put("java.util.Deque", splitMembers(""));
index.put("java.util.Dictionary", splitMembers(""));
index.put("java.util.EmptyStackException", splitMembers(""));
index.put("java.util.Enumeration", splitMembers(""));
Expand Down Expand Up @@ -2476,17 +2478,18 @@ private static void fillFieldIndex9(Map<String, String[]> index) {
index.put("com.codenameone.playground.CN1Playground", splitMembers(""));
index.put("com.codenameone.playground.PlaygroundContext", splitMembers(""));
index.put("com.codenameone.playground.PlaygroundContext.Logger", splitMembers(""));
index.put("com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter", splitMembers(""));
index.put("com.codenameone.playground.PlaygroundLambdaBridge", splitMembers(""));
index.put("com.codenameone.playground.PlaygroundListenerBridge", splitMembers(""));
index.put("com.codenameone.playground.WebsiteThemeNative", splitMembers(""));
index.put("java.io.ByteArrayInputStream", splitMembers(""));
index.put("java.io.ByteArrayOutputStream", splitMembers(""));
index.put("java.io.DataInput", splitMembers(""));
index.put("java.io.DataInputStream", splitMembers(""));
index.put("java.io.DataOutput", splitMembers(""));
}

private static void fillFieldIndex10(Map<String, String[]> index) {
index.put("java.io.DataOutput", splitMembers(""));
index.put("java.io.DataOutputStream", splitMembers(""));
index.put("java.io.EOFException", splitMembers(""));
index.put("java.io.Flushable", splitMembers(""));
Expand Down Expand Up @@ -2550,10 +2553,10 @@ private static void fillFieldIndex10(Map<String, String[]> index) {
index.put("java.lang.OutOfMemoryError", splitMembers(""));
index.put("java.lang.Override", splitMembers(""));
index.put("java.lang.Runnable", splitMembers(""));
index.put("java.lang.Runtime", splitMembers(""));
}

private static void fillFieldIndex11(Map<String, String[]> index) {
index.put("java.lang.Runtime", splitMembers(""));
index.put("java.lang.RuntimeException", splitMembers(""));
index.put("java.lang.SafeVarargs", splitMembers(""));
index.put("java.lang.SecurityException", splitMembers(""));
Expand Down Expand Up @@ -2617,10 +2620,10 @@ private static void fillFieldIndex11(Map<String, String[]> index) {
index.put("java.util.Comparator", splitMembers(""));
index.put("java.util.ConcurrentModificationException", splitMembers(""));
index.put("java.util.Date", splitMembers(""));
index.put("java.util.Deque", splitMembers(""));
}

private static void fillFieldIndex12(Map<String, String[]> index) {
index.put("java.util.Deque", splitMembers(""));
index.put("java.util.Dictionary", splitMembers(""));
index.put("java.util.EmptyStackException", splitMembers(""));
index.put("java.util.Enumeration", splitMembers(""));
Expand Down
34 changes: 32 additions & 2 deletions ...ayground/common/src/main/java/bsh/cn1/gen/GeneratedAccess_com_codenameone_playground.java
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,9 @@ private static Class<?> findClassChunk0(String simpleName) {
if ("Logger".equals(simpleName)) {
return com.codenameone.playground.PlaygroundContext.Logger.class;
}
if ("RuntimeErrorReporter".equals(simpleName)) {
return com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter.class;
}
if ("PlaygroundLambdaBridge".equals(simpleName)) {
return com.codenameone.playground.PlaygroundLambdaBridge.class;
}
Expand All @@ -51,6 +54,10 @@ public static Object construct(Class<?> type, Object[] args) throws Exception {
Object[] adaptedArgs = adaptArgs(safeArgs, new Class<?>[]{com.codename1.ui.Form.class, com.codename1.ui.Container.class, com.codename1.ui.util.Resources.class, com.codenameone.playground.PlaygroundContext.Logger.class}, false);
return new com.codenameone.playground.PlaygroundContext((com.codename1.ui.Form) adaptedArgs[0], (com.codename1.ui.Container) adaptedArgs[1], (com.codename1.ui.util.Resources) adaptedArgs[2], (com.codenameone.playground.PlaygroundContext.Logger) adaptedArgs[3]);
}
if (matches(safeArgs, new Class<?>[]{com.codename1.ui.Form.class, com.codename1.ui.Container.class, com.codename1.ui.util.Resources.class, com.codenameone.playground.PlaygroundContext.Logger.class, com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter.class}, false)) {
Object[] adaptedArgs = adaptArgs(safeArgs, new Class<?>[]{com.codename1.ui.Form.class, com.codename1.ui.Container.class, com.codename1.ui.util.Resources.class, com.codenameone.playground.PlaygroundContext.Logger.class, com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter.class}, false);
return new com.codenameone.playground.PlaygroundContext((com.codename1.ui.Form) adaptedArgs[0], (com.codename1.ui.Container) adaptedArgs[1], (com.codename1.ui.util.Resources) adaptedArgs[2], (com.codenameone.playground.PlaygroundContext.Logger) adaptedArgs[3], (com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter) adaptedArgs[4]);
}
}
throw unsupportedConstruct(type, safeArgs);
}
Expand Down Expand Up @@ -126,9 +133,16 @@ public static Object invoke(Object target, String name, Object[] args) throws Ex
unsupported = ex;
}
}
if (target instanceof com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter) {
try {
return invoke5((com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter) target, name, safeArgs);
} catch (CN1AccessException ex) {
unsupported = ex;
}
}
if (target instanceof com.codenameone.playground.WebsiteThemeNative) {
try {
return invoke5((com.codenameone.playground.WebsiteThemeNative) target, name, safeArgs);
return invoke6((com.codenameone.playground.WebsiteThemeNative) target, name, safeArgs);
} catch (CN1AccessException ex) {
unsupported = ex;
}
Expand Down Expand Up @@ -248,6 +262,12 @@ private static Object invoke1(com.codenameone.playground.PlaygroundContext typed
typedTarget.refreshPreview(); return null;
}
}
if ("reportRuntimeError".equals(name)) {
if (matches(safeArgs, new Class<?>[]{java.lang.String.class, java.lang.Throwable.class}, false)) {
Object[] adaptedArgs = adaptArgs(safeArgs, new Class<?>[]{java.lang.String.class, java.lang.Throwable.class}, false);
typedTarget.reportRuntimeError((java.lang.String) adaptedArgs[0], (java.lang.Throwable) adaptedArgs[1]); return null;
}
}
if ("setTitle".equals(name)) {
if (matches(safeArgs, new Class<?>[]{java.lang.String.class}, false)) {
Object[] adaptedArgs = adaptArgs(safeArgs, new Class<?>[]{java.lang.String.class}, false);
Expand Down Expand Up @@ -309,7 +329,17 @@ private static Object invoke4(com.codenameone.playground.PlaygroundContext.Logge
throw unsupportedInstance(typedTarget, name, safeArgs);
}

private static Object invoke5(com.codenameone.playground.WebsiteThemeNative typedTarget, String name, Object[] safeArgs) throws Exception {
private static Object invoke5(com.codenameone.playground.PlaygroundContext.RuntimeErrorReporter typedTarget, String name, Object[] safeArgs) throws Exception {
if ("reportRuntimeError".equals(name)) {
if (matches(safeArgs, new Class<?>[]{java.lang.String.class, java.lang.Throwable.class}, false)) {
Object[] adaptedArgs = adaptArgs(safeArgs, new Class<?>[]{java.lang.String.class, java.lang.Throwable.class}, false);
typedTarget.reportRuntimeError((java.lang.String) adaptedArgs[0], (java.lang.Throwable) adaptedArgs[1]); return null;
}
}
throw unsupportedInstance(typedTarget, name, safeArgs);
}

private static Object invoke6(com.codenameone.playground.WebsiteThemeNative typedTarget, String name, Object[] safeArgs) throws Exception {
if ("isDarkMode".equals(name)) {
if (safeArgs.length == 0) {
return typedTarget.isDarkMode();
Expand Down
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