skylot/jadx · error · JadxRuntimeException

Expected to find block info within {}

Error message

Expected to find block info within {}

What it means

Thrown by BaseBlockTraverserHandler.handle() when the current TraverserState's getBlockInsnInfo() returns null. The finally-block traverser subsystem requires every block-level handler state to carry a TraverserBlockInfo (the active block and its instruction offsets). A null value means the state type does not track an active block (e.g. a terminal, global, or cache-recovery state was incorrectly routed to this handler). This is an internal invariant violation in jadx's 'finaly' (finally-extraction) visitor pipeline, not a user-configuration error.

Source

Thrown at jadx-core/src/main/java/jadx/core/dex/visitors/finaly/traverser/handlers/BaseBlockTraverserHandler.java:27

import jadx.core.dex.visitors.finaly.traverser.visitors.ImplicitInsnBlockTraverserVisitor;
import jadx.core.dex.visitors.finaly.traverser.visitors.PathEndBlockTraverserVisitor;
import jadx.core.utils.exceptions.JadxRuntimeException;

public class BaseBlockTraverserHandler extends AbstractBlockPathTraverserHandler {

	public BaseBlockTraverserHandler(TraverserState initialState) {
		super(initialState);
	}

	public BaseBlockTraverserHandler(AtomicReference<TraverserState> initialStateRef) {
		super(initialStateRef);
	}

	@Override
	protected void handle() {
		TraverserBlockInfo blockInsnInfo = getState().getBlockInsnInfo();
		if (blockInsnInfo == null) {
			throw new JadxRuntimeException("Expected to find block info within " + getClass().getSimpleName());
		}
		TraverserActivePathState comparator = getState().getComparatorState();
		AtomicReference<TraverserState> stateRef = comparator.getReferenceForState(getState());
		if (stateRef == null) {
			throw new JadxRuntimeException("Orphaned traverser state");
		}
		BlockNode block = blockInsnInfo.getBlock();
		ImplicitInsnBlockTraverserVisitor implicitVisitor = new ImplicitInsnBlockTraverserVisitor(getState());
		TraverserState stateAfterImplicit = implicitVisitor.visit(block);
		PathEndBlockTraverserVisitor pathEndVisitor = new PathEndBlockTraverserVisitor(stateAfterImplicit);
		TraverserState nextState = pathEndVisitor.visit(block);

		stateRef.set(nextState);
	}
}

View on GitHub (pinned to e738a26571)

Solutions

1. Report the issue to the jadx project with the input file and full stack trace — this is an internal decompiler bug in the finally visitor.
2. As a workaround, disable finally extraction by passing the decompiler argument to skip the finally pass (e.g. --no-debug-info or relevant visitor skip flags) and re-run.
3. Try a different jadx version — the finally traverser is under active development and the edge case may be fixed in a newer release.
4. If developing jadx itself, add a null check and inspect which concrete TraverserState subclass is being dispatched to a block handler; the state's getNextHandler() is returning the wrong handler type.

// Before dispatching a state to a block handler, verify it carries block info
TraverserBlockInfo info = state.getBlockInsnInfo();
if (info == null) {
    // Skip or route to a non-block handler instead of throwing
    return;
}

When it happens

Trigger: A TraverserState subclass whose getUnderlyingBlockInsnInfo() returns null (such as TerminalTraverserState, a global source state, or a cache-recovery wrapper) is passed into a BaseBlockTraverserHandler via the traverser controller's getNextHandler() dispatch. This happens when a state transition produces a non-block state but the controller still routes it to a block-handling handler.

Common situations: Decompiling an APK/JAR that contains complex or unusual try-finally control flow that the finally-extraction algorithm does not handle. Rarely triggered on typical inputs; almost always indicates a logic gap in the finally visitor for a specific bytecode shape (e.g. nested finally blocks, finally blocks with exception handlers, or synthetic compiler-generated control flow).

Related errors

• Unknown global traverser state. Has a global state been dupl
• Orphaned TraverserState node
• Orphaned traverser state
• Orphaned traverser state
• Attempted to get instructions slice of block {} with {} skip

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/80edcc3d9d471233. Report an issue: GitHub.