fix: catch panics from external light-* crates in V2 parser

[i-am-bert]

Problem

Both pitt and fra Photon ingestors stuck at slot 407265370. light-event v0.21.0 panics in create_batched_transaction_event → create_nullifier_queue_indices with index out of bounds: the len is 3 but the index is 3.

Root Cause

create_nullifier_queue_indices() in light-event has a size mismatch bug:

1. batch_input_accounts is built by filtering nullifiers to only those matching input_sequence_numbers
2. create_nullifier_queue_indices(len) receives len = batch_input_accounts.len() (the filtered count)
3. Inside, it creates nullifier_queue_indices = vec![u64::MAX; len] (sized to filtered count)
4. But then iterates over all input_compressed_accounts by index i, accessing nullifier_queue_indices[i]
5. When input_compressed_accounts.len() > batch_input_accounts.len() (i.e. some nullifiers were filtered out), i exceeds len → panic

This bug exists in both v0.21.0 and v0.23.0 of light-event.

graph TD
    A[nullifiers array - 4 items] -->|filter by input_sequence_numbers| B[batch_input_accounts - 3 items]
    B -->|.len| C["len = 3"]
    C --> D["nullifier_queue_indices = vec![MAX; 3]"]
    E[input_compressed_accounts - 4 items] -->|iterate by index i| F["i goes 0,1,2,3"]
    F -->|"access [3]"| D
    D -->|"len is 3, index is 3"| G["💥 PANIC"]

Loading

Fix (two layers)

1. Root cause fix: Patch light-event (light-event-patched/)

Vendored light-event v0.21.0 with [patch.crates-io] override. Fixed create_nullifier_queue_indices to size the vec to input_merkle_tree_pubkeys.len() (the array actually being indexed), not the filtered batch_input_accounts count. The caller zips with batch_input_accounts, so extra entries are harmlessly ignored.

2. Safety net: catch_unwind in V2 parser (src/ingester/parser/mod.rs)

Wraps parse_public_transaction_event_v2() in catch_unwind(AssertUnwindSafe(...)) to prevent any future panic from external light-* crates from halting the ingestor. On caught panic: logs tx sig + slot + panic message, emits parser_panic_caught StatsD metric, returns None.

Testing

• cargo check passes cleanly
• The root cause fix ensures the panicking transaction at slot 407265370 will parse correctly — no data loss
• The safety net ensures future unknown panics degrade gracefully instead of halting indexing

Upstream

Bug exists in light-event v0.21.0 and v0.23.0. Will file upstream issue on lightprotocol/light-protocol.

[i-am-bert]

Superseded by #341 (clean version bump to light-event 0.24). The vendored patch approach is no longer needed.