fix: double deinit of response buffer on non-200 HTTP responses

[lukemacauley]

Summary

HttpTransport.request and requestBatch call response_body.deinit() explicitly on the non-200 and connection-failure paths, then return an error — which also runs the errdefer response_body.deinit() on the same std.Io.Writer.Allocating. That's a double free. In ReleaseFast (how gator-liquidators ships) it's UB and manifests as a silent SIGSEGV instead of error.HttpError.

Impact

This took down the PerpCity production liquidator for ~19 hours on 2026-07-30/31: the team's Alchemy quota ran out, Alchemy started answering every call with HTTP status 429, and gator segfaulted (exit 139, no output) within seconds of each boot — a once-a-minute ECS crash loop for the entire outage window, during exactly the kind of event where a liquidator matters most. Any sustained non-200 from an RPC endpoint (rate limits, gateway 502s, provider incidents) triggers it.

Repro: point gator-liquidators at any endpoint returning a non-200 (Debug build reports the double free at http_transport.zig; the crash address is the 0xAA undefined-fill pattern).

Fix

Drop the explicit deinit() calls and let the errdefer own cleanup on all error paths. Two-line-pair deletion, no behavior change on success paths.

Test

Adds a regression test that runs a real localhost TCP server answering 429 Too Many Requests and asserts request() returns error.HttpError twice in a row. On the old code the testing allocator aborts with a double-free report; on the fixed code all tests pass. Verified the fixed build end-to-end against the live capacity-limited Alchemy endpoint: clean error.HttpError cycles with backoff, no crash.

After merge/release, gator-liquidators needs a bump from eth.zig v0.8.1 to pick this up.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved reliability when handling HTTP error responses.
  • Prevented memory-management issues during repeated failed requests.
  • Added coverage for repeated requests receiving HTTP 429 responses.

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Project	Deployment	Actions	Updated (UTC)
eth-zig	Ready	Preview	Jul 31, 2026 1:40pm

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 967df59f-8472-49a5-91c2-765967ae8a7d

📥 Commits

Reviewing files that changed from the base of the PR and between 9da2547 and 204178d.

📒 Files selected for processing (1)

• src/http_transport.zig

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📝 Walkthrough

Walkthrough

The HTTP transport removes duplicate response-buffer cleanup from HTTP error paths. A local-server integration test sends two HTTP 429 requests and verifies that both return error.HttpError without allocator corruption.

Changes

HTTP error response cleanup

Layer / File(s)	Summary
Deferred cleanup and repeated error validation src/http_transport.zig	HTTP status-error paths rely on errdefer for response-buffer cleanup. The integration test repeats HTTP 429 requests and verifies error.HttpError results.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: koko1123

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely identifies the double deinitialization fix for response buffers on non-200 HTTP responses.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/http-transport-double-deinit

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