I now have a thorough understanding of this PR. Let me analyze the changes:

Summary: This PR adds an isDynamicWorker flag to ArtifactBundler_State and exposes it to the Python runtime via JSG so that checkSnapshotType() in snapshot.ts can skip snapshot type validation for dynamic workers that don't yet support dedicated snapshots.

Analysis:

1. C++ changes (pyodide.h): New bool isDynamicWorkerFlag field, constructor parameter with default false, propagated in clone(), exposed via JSG_METHOD. Clean and straightforward. Default parameter means existing callers are unaffected.

2. TypeScript changes: New IS_DYNAMIC_WORKER export, used in checkSnapshotType() to early-return before the mismatch validation. Type declaration added.

3. Backward compatibility: The constructor has isDynamicWorker = false as a default parameter, so all existing call sites (in server.c++, worker-modules.h) continue to work unchanged. No behavioral change for non-dynamic workers.

4. Security: The flag only skips a validation that throws an internal error when snapshot type doesn't match the compat flag. It doesn't grant any new capabilities or bypass sandbox restrictions. The flag is set server-side, not by user code.

5. No tests: There are no tests for this change. However, this is a narrow fix for a specific production issue with Python dynamic workers, and the checkSnapshotType function itself has no existing tests either. The code path is clearly correct — when a dynamic worker receives a baseline snapshot but has dedicated snapshot compat flag enabled, it should not throw.

6. One potential concern: The early return in checkSnapshotType skips ALL validation for dynamic workers, including the check that throws when a dedicated snapshot is received but the compat flag is NOT enabled (lines 773-781), and the second validation phase check (lines 796-801). The comment says "Dynamic workers don't yet support dedicated snapshots", so skipping all checks is reasonable for now, but it means if a dynamic worker somehow receives a dedicated snapshot, no error will be raised.

This is a clean, well-scoped bugfix. The code is correct and the approach is sound. There are no actionable issues.

LGTM

github run

Merging this PR will improve performance by 12.73%

⚡ 1 improved benchmark
✅ 69 untouched benchmarks
⏩ 129 skipped benchmarks¹

Performance Changes

_{Comparing dominik/EW-10700 (550daf0) with main (0d830b1)}