ci(native): run the tests against a UBSan build of the addon by ThomasK33 · Pull Request #33 · coder/libghostty-vt-node

ThomasK33 · 2026-10-29T21:14:01Z

Why

CI must fail by itself when the native addon hits undefined behavior again. A normal build of the out-of-range casts that #30 fixed passed every test, so only a sanitizer build catches that kind of bug. This PR adds that build to CI.

What changed

mise.toml gets a ci-ubsan task. It builds the addon with -fsanitize=undefined,float-cast-overflow -fno-sanitize-recover=all, then runs npm test and npm run smoke.
A guard step after the build fails the task when the addon's object files hold no UBSan checks, so the row cannot pass on a plain build.
.github/workflows/ci.yml gives every matrix row a task column and adds a linux-x64-ubsan row that runs ci-ubsan.
native/README.md and README.md name the task in their verification sections.

Scope

The sanitizer runs on Linux x64 with GCC only. The other rows keep the plain ci task.
It instruments the addon's C++ code. Zig builds libghostty-vt as before.
AddressSanitizer and other sanitizers are left out.

Tradeoffs

A matrix row, not a second job. One job definition stays, and the task column says what each row runs.
The flags apply to the build:native step only, so npm ci and the Zig build of libghostty-vt never see them.
No LD_PRELOAD. The UBSan handlers that Zig bundles in libghostty-vt.a take every report and abort the process. The addon also links libubsan.so.1 as a fallback.
The guard reads the object files, not the final .node. The .node carries Zig's handlers in every build, so it cannot show whether g++ got the flags.

Blast radius

CI gets one more Linux job about as long as the ci row. The published package changes only by one line in each of README.md and native/README.md.

Verification

Local run, GCC 15.2 on linux-x64. On main, the sanitized build passes 40 of 40 tests and smoke. With the pre-fix(native): range-check dimensions before casting them #30 native/terminal.cc, npm test exits 1 with panic: nan is outside the range of representable values of type 'unsigned int'.
Guard, local run: it exits 0 after the sanitized build, and exits 1 after a plain build or with no build/ folder.
g++ -fsanitize=undefined alone emits no float-cast check. Adding float-cast-overflow emits it, which is why the flag list names it.
GitHub Actions run 40955931001 used a throwaway branch with the pre-fix(native): range-check dimensions before casting them #30 native/terminal.cc. The linux-x64-ubsan row failed with the same nan panic, and the plain linux-x64 row passed. The plain arm64 rows also failed, on the fix(native): range-check dimensions before casting them #30 test for scrollbackLimit: 2^64.

Generated with xum • Model: anthropic:claude-opus-5-5 • Thinking: xhigh

A normal build of the out-of-range casts fixed in #30 passes every test. Add a ci-ubsan mise task that builds only the addon with -fsanitize=undefined,float-cast-overflow and no recovery, then runs the tests and smoke. CI runs it as a linux-x64-ubsan matrix row, and every row now names its mise task. _Generated with [`xum`](https://github.com/coder/xum) • Model: `anthropic:claude-opus-5-5` • Thinking: `medium`_ Change-Id: Iad93613b401f2b4c82346d12b851dc9dc779dac5 Signed-off-by: Thomas Kosiewski <tk@coder.com>

ThomasK33 · 2026-10-29T21:14:16Z

@codex review

ThomasK33 · 2026-10-29T21:14:21Z

@codex security review

chatgpt-codex-connector · 2026-10-29T21:14:29Z

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-29T21:42:08.160801Z	`ffecdc2`	Manual request
🔒 Security Review	✅ Completed 2026-10-29T21:42:06.447978Z	`ffecdc2`	Manual request

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chatgpt-codex-connector · 2026-10-29T21:15:42Z

Codex Review: Didn't find any major issues. What shall we delve into next?

Reviewed commit: 46a5afe8ef

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chatgpt-codex-connector · 2026-10-29T21:16:17Z

🛡️ Codex Security Review

Security review completed. No security issues were found in this pull request.

Reviewed commit: 46a5afe8ef

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If the sanitizer flags stop reaching g++, the ubsan row would build a plain addon and stay green. The new step checks the addon's own object files for undefined UBSan _abort handlers. The final .node cannot show this, because libghostty-vt.a always carries Zig's handlers. _Generated with [`xum`](https://github.com/coder/xum) • Model: `anthropic:claude-opus-5-5` • Thinking: `low`_ Change-Id: I5e7cd4b708ad8e7f17356cb9e4da8cecf15c75b9 Signed-off-by: Thomas Kosiewski <tk@coder.com>

ThomasK33 · 2026-10-29T21:32:33Z

@codex review

ThomasK33 · 2026-10-29T21:32:38Z

@codex security review

chatgpt-codex-connector · 2026-10-29T21:34:33Z

🛡️ Codex Security Review

Security review completed. No security issues were found in this pull request.

Reviewed commit: dcb68251f7

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chatgpt-codex-connector

💡 Codex Review

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Reviewed commit: dcb68251f7

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mise runs each step with pipefail. grep -q exits on its first match, so nm can die of SIGPIPE and the guard fails a correctly instrumented build with exit 141. grep -c reads to the end and still exits 1 when nothing matches. _Generated with [`xum`](https://github.com/coder/xum) • Model: `anthropic:claude-opus-5-5` • Thinking: `low`_ Change-Id: I17c4f080629226f6dfb27d9354923d7a31ac382b Signed-off-by: Thomas Kosiewski <tk@coder.com>

ThomasK33 · 2026-10-29T21:40:29Z

@codex review

ThomasK33 · 2026-10-29T21:40:35Z

@codex security review

chatgpt-codex-connector · 2026-10-29T21:42:05Z

🛡️ Codex Security Review

Security review completed. No security issues were found in this pull request.

Reviewed commit: ffecdc20f7

View security finding report

Only the user who started this review can view the report in Codex.

ℹ️ About Codex security reviews in GitHub

This is an experimental Codex feature. Security reviews are triggered when:

You comment "@codex security review"
A regular code review gets triggered (for example, "@codex review" or when a PR is opened), and you’re opted in so security review runs alongside code review

Once complete, Codex will leave suggestions, or a comment if no findings are found.

chatgpt-codex-connector · 2026-10-29T21:42:06Z

Codex Review: Didn't find any major issues. Can't wait for the next one!

Reviewed commit: ffecdc20f7

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ThomasK33 · 2026-10-29T22:09:45Z

Merge record for this PR.

Landed as 96fb41b (squash, linear history). Its tree equals the tested head ffecdc2.
CI: all four rows passed on ffecdc2 and on main at 96fb41b, including the new ci (linux-x64-ubsan).
Red check: workflow run 40955931001, on a throwaway branch with the pre-fix(native): range-check dimensions before casting them #30 native/terminal.cc, failed the UBSan row with panic: nan is outside the range of representable values of type 'unsigned int'. The branch is deleted.
Reviews: 3 Codex rounds of 6. Round 2 found one valid P1: grep -q gets SIGPIPE under mise's pipefail. It was fixed in ffecdc2, and its thread is resolved. Round 3 was clean in both lanes, and a 6-minute grace check stayed clean.
Advisor (fresh context, one pass): "ready with tracked follow-ups". Both follow-ups landed in this PR: the object-file guard and the corrected handler claim in the body.
Approval: main requires 1 approving review, and the author cannot approve. The owner consented to an admin bypass for this PR.
Known limit: the guard proves that -fsanitize and -fno-sanitize-recover reached g++, but not float-cast-overflow itself, because the fixed addon code has no float cast left to check. The red-check run proved that flag once.

Generated with xum • Model: anthropic:claude-opus-5-5 • Thinking: xhigh

chatgpt-codex-connector Bot reviewed Oct 29, 2026

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Comment thread mise.toml Outdated

ThomasK33 merged commit 96fb41b into main Oct 29, 2026
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ThomasK33 mentioned this pull request Oct 30, 2026

Release v0.1.0-beta.2 #44

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