[Bug]: Bytecode index out of range instead of the guest exception when it passes a try/finally or try/except-raise frame #1186

Describe the bug

A Python exception raised in code run by exec() reaches Java through a Python function with a
try/finally or try/except … raise. When the embedding JVM runs with -ea, Java receives
java.lang.IllegalArgumentException: Bytecode index out of range <n> instead of a
PolyglotException for the guest error. The original error is lost.

Without -ea, the same code produces the expected PolyglotException. Test suites usually run with
-ea; JUnit through Gradle and Maven Surefire both enable it.

Without -ea nothing is thrown, but the stack trace is wrong (see Additional context), so the line of the failing user code is lost in both cases.

Operating system

Linux (x86_64, WSL2)

CPU architecture

x86_64

GraalPy version

• JDK: Temurin 25.0.4+7, Linux x86_64 (WSL2), interpreter-only runtime (stock JDK).
• Regression range: first seen in 25.1, which is presumably where the Bytecode DSL interpreter
  became the only one. python.EnableBytecodeDSLInterpreter no longer exists in 25.4.

JDK version

Temurin 25.0.4+7 (stock OpenJDK, interpreter-only runtime)

Context configuration

Context.create("python"). The issue also shows with a shared Engine, HostAccess.ALL and IOAccess.NONE.

Steps to reproduce

Standalone reproducer, Gradle wrapper included: https://github.com/BigMichi1/graalpy-reraise-stacktrace
(./gradlew -q run -Pea; the README lists the other modes and the version sweep).

Run this Java program with -ea on a stock JDK 25 (Temurin 25.0.4), with
org.graalvm.polyglot:polyglot and org.graalvm.polyglot:python-community:

import org.graalvm.polyglot.*;

public class ReraiseRepro {
    static final String SUPPORT = """
            def plain(code):
                exec(code, {})

            def with_finally(code):
                try:
                    exec(code, {})
                finally:
                    pass

            def with_except(code):
                try:
                    exec(code, {})
                except BaseException:
                    raise
            """;

    public static void main(String[] args) {
        try (Context context = Context.create("python")) {
            context.eval("python", SUPPORT);
            Value bindings = context.getBindings("python");
            for (String fn : new String[] {"plain", "with_finally", "with_except"}) {
                for (String code : new String[] {"undefined_name", "raise ValueError('boom')", "1 / 0"}) {
                    try {
                        bindings.getMember(fn).execute(code);
                    } catch (PolyglotException e) {
                        System.out.printf("%s(%s): ok  %s%n", fn, code, e.getMessage());
                    } catch (RuntimeException e) {
                        System.out.printf("%s(%s): BUG %s%n", fn, code, e);
                    }
                }
            }
        }
    }
}

Output with -ea on 25.4.4.1.1:

plain(undefined_name): ok  NameError: name 'undefined_name' is not defined
plain(raise ValueError('boom')): ok  ValueError: boom
plain(1 / 0): ok  ZeroDivisionError: division by zero
with_finally(undefined_name): BUG java.lang.IllegalArgumentException: Bytecode index out of range 114
with_finally(raise ValueError('boom')): BUG java.lang.IllegalArgumentException: Bytecode index out of range 114
with_finally(1 / 0): ok  ZeroDivisionError: division by zero
with_except(undefined_name): BUG java.lang.IllegalArgumentException: Bytecode index out of range 168
with_except(raise ValueError('boom')): BUG java.lang.IllegalArgumentException: Bytecode index out of range 168
with_except(1 / 0): ok  ZeroDivisionError: division by zero

1 / 0 is not affected. NameError and an explicit raise are.

Steps

1. Build the program above against polyglot and python-community 25.4.4.1.1.
2. Run it with java -ea --enable-native-access=ALL-UNNAMED ReraiseRepro.
3. Run it again without -ea: every case prints ok.

Expected behavior

The exception is a PolyglotException carrying the guest NameError or ValueError, with or
without -ea.

Stack trace

java.lang.IllegalArgumentException: Bytecode index out of range 168
    at com.oracle.graal.python.nodes.bytecode_dsl.PBytecodeDSLRootNodeGen$AbstractBytecodeNode.validateBytecodeIndex(PBytecodeDSLRootNodeGen.java:6926)
    at com.oracle.truffle.api.bytecode.BytecodeNode.getBytecodeLocation(BytecodeNode.java:151)
    at com.oracle.truffle.api.bytecode.BytecodeLocation.get(BytecodeLocation.java:326)
    at com.oracle.truffle.api.bytecode.BytecodeLocation.get(BytecodeLocation.java:350)
    at com.oracle.truffle.api.bytecode.DefaultBytecodeStackTraceElement.getSourceSectionImpl(DefaultBytecodeStackTraceElement.java:105)
    at com.oracle.truffle.api.bytecode.DefaultBytecodeStackTraceElement.hasSourceLocation(DefaultBytecodeStackTraceElement.java:88)
    at com.oracle.truffle.api.bytecode.DefaultBytecodeStackTraceElementGen$InteropLibraryExports$Uncached.hasSourceLocation(DefaultBytecodeStackTraceElementGen.java:188)
    at com.oracle.truffle.api.interop.InteropLibrary$Asserts.hasSourceLocation(InteropLibrary.java:5246)
    at com.oracle.truffle.api.interop.InteropLibraryGen$UncachedDispatch.hasSourceLocation(InteropLibraryGen.java:8163)
    at com.oracle.truffle.polyglot.PolyglotExceptionFrame.create(PolyglotExceptionFrame.java:235)
    at com.oracle.truffle.polyglot.PolyglotExceptionImpl$FrameGuestObjectIterator.fetchNext(PolyglotExceptionImpl.java:645)
    ...
    at org.graalvm.polyglot.PolyglotException.<init>(PolyglotException.java:122)
    at org.graalvm.polyglot.Engine$APIAccessImpl.newLanguageException(Engine.java:1345)
    at com.oracle.truffle.polyglot.PolyglotImpl.guestToHostException(PolyglotImpl.java:1240)
    at com.oracle.truffle.polyglot.HostToGuestRootNode.handleException(HostToGuestRootNode.java:148)
    at org.graalvm.polyglot.Value.execute(Value.java:1100)

Additional context

• The failure happens while the polyglot exception's stack trace is materialized. A bytecode
  stack-trace element of the frame with the handler carries a bytecode index outside its
  BytecodeNode.

• Without -ea the stack trace is silently wrong. For a source named support.py with
  with_except on lines 1-5 and plain on lines 6-7, executing "x = 1\nundefined_name" gives
  these guest frames from PolyglotException.getPolyglotStackTrace():

  plain:
     <python> <module>(<string>:2:6-19)
     <python> plain(support.py:7:116-129)
  with_except:
     <python> with_except(Unknown)
  

  Through the handler frame, the frame of the exec'd code (<module>, line 2) is missing, and
  the handler frame itself has no location. An embedder therefore cannot report the failing line
  of a user script.

• Workaround in our JSR-223 engine: no exception handler in the Python frame that exec()s user
  code; cleanup runs as a separate call from Java.