Chunk 1.0

The assistant then diagnosed a deeper inconsistency in the PCE witness generation path. The previous fix made `RecordingCS` extensible, but the witness side (using `WitnessCS`) still produced a different number of inputs than the standard prover (using `ProvingAssignment`). The root cause was that `WitnessCS::new()` pre-allocated the ONE input, while `ProvingAssignment::new()` started empty. When `synthesize_extendable` created child CS instances, `WitnessCS` children had an extra input that survived the `extend()` call, leading to the `num_inputs` mismatch. The fix harmonized all three CS types (`WitnessCS`, `RecordingCS`, `ProvingAssignment`) to start with zero inputs, with the ONE input explicitly allocated by the caller before synthesis. This resolved the WindowPoSt PCE crash. Following the fix, the user requested a documentation update to add `protobuf-compiler` to the installation guides for all supported distros, which the assistant completed. The user then deployed the code to a remote calibnet host. However, a new issue emerged: PoRep proofs were failing with random partition invalidity (e.g., 7/10 valid on one run, 1/10 on retry). The non-deterministic nature of the failures pointed to a data race, stale PCE data, or a randomness issue in the GPU proving path, rather than a pure synthesis bug. Investigation on the remote host revealed that the PoRep PCE file was missing (only a `.tmp` file existed), suggesting the PCE was corrupted or from a previous incomplete run. The assistant attempted to build and deploy the latest code to rule out stale build issues, but the remote host lacked `cargo` in its PATH, stalling the deployment. The investigation into the random PoRep partition failures remains ongoing, with the primary hypothesis being that the stale build and missing/corrupted PCE are the root cause.

From Fix to Failure: How Deploying a Constraint System Harmonization Fix Revealed a Deeper GPU Race Condition 2534 words

Message Articles

Subagent Sessions