oracle/graal · error · IOException

Invalid replay registration index

Error message

Invalid replay registration index

What it means

IOException thrown by BinaryReplayCodec.ReadState.registrationAt when a registration index is outside [0, registrations.length). registrations is the fixed CompilerInterfaceDeclarations array for the running build; an out-of-range index means the stream was written against a different set of registered compiler-interface types — i.e. a build/version mismatch or corrupt data.

Source

Thrown at compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/replaycomp/BinaryReplayCodec.java:280

        }

        private CompilationProxy.SymbolicMethod methodAt(int index) throws IOException {
            if (index < 0 || index >= methodTable.size()) {
                throw new IOException("Invalid replay symbolic method index " + index);
            }
            return methodTable.get(index);
        }

        private void defineMethod(int index, CompilationProxy.SymbolicMethod method) throws IOException {
            if (index != methodTable.size()) {
                throw new IOException("Invalid replay symbolic method definition index " + index);
            }
            methodTable.add(method);
        }

        private CompilerInterfaceDeclarations.Registration registrationAt(int index) throws IOException {
            if (index < 0 || index >= registrations.length) {
                throw new IOException("Invalid replay registration index " + index);
            }
            return registrations[index];
        }

        private Object singletonProxy(int registrationIndex) throws IOException {
            CompilerInterfaceDeclarations.Registration registration = registrationAt(registrationIndex);
            if (!registration.singleton()) {
                throw new IOException("Registration " + registration.clazz().getName() + " is not a singleton");
            }
            Object proxy = singletonProxies[registrationIndex];
            if (proxy == null) {
                proxy = proxyFactory.createProxy(registration);
                singletonProxies[registrationIndex] = proxy;
            }
            return proxy;
        }

        private Object instanceProxy(int registrationIndex, int id) throws IOException {

View on GitHub (pinned to a66e9ccd1d)

Solutions

  1. Re-capture replay data on the exact compiler build performing replay.
  2. Confirm the replay file was not truncated or modified.
  3. Pin replay workflow (record + replay) to one build in CI.
Defensive patterns

Strategy: validation

Validate before calling

// Compare registration counts before decoding: reader's registrations must match writer's
int readers = CompilerInterfaceDeclarations.getRegistrations().length; // reader side
if (readers != recordedRegistrationCount) {
    throw new IOException("Replay file written against a different CompilerInterface set");
}

Try / catch

try {
    replayCodec.decode(input);
} catch (IOException e) {
    if (e.getMessage().startsWith("Invalid replay registration index")) {
        // build mismatch: regenerate replay data on this build
    }
    throw e;
}

Prevention

When it happens

Trigger: Reading a replay file where a proxy reference uses a registration index beyond the current build's registrations array — happens when the producing build registered more/fewer CompilerInterface types than the consuming build.

Common situations: Replaying profiles captured on another Graal revision whose compiler-interface registrations differ; truncated or edited replay files.

Related errors

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/fdc952ab9bd6f841. Report an issue: GitHub.