worker-protocol: add cancelled-and-hash-mismatch-status feature by amaanq · Pull Request #15090 · NixOS/nix

amaanq · 2026-01-26T21:52:24Z

Motivation

This commit adds a cancelled-and-hash-mismatch-status protocol feature that gates two new BuildResult failure statuses: HashMismatch (a specific type of OutputRejected for hash mismatches) and Cancelled (for goals never attempted because another goal failed without --keep-going). Goals now default to Cancelled status instead of MiscFailure. When communicating with older remotes, HashMismatch falls back to OutputRejected and Cancelled falls back to MiscFailure.

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src/libstore/include/nix/store/build-result.hh

src/libcmd/installables.cc

src/libstore/build/worker.cc

src/libstore/common-protocol.cc

Ericson2314

Please make a first PR that just introduces ExitStatusFlags (and does the things I mention below). Then we'll return to this one for the actual wire protocol changes using it.

dpulls · 2026-01-30T19:21:43Z

🎉 All dependencies have been resolved !

src/libstore-tests/worker-protocol.cc

Ericson2314 · 2026-02-06T21:49:05Z

src/libstore/include/nix/store/build/goal.hh

     * Build result.
     */
-    BuildResult buildResult;
+    BuildResult buildResult = {.inner = BuildResult::Failure{BuildResult::Failure::Cancelled, ""}};


N.B. tempted to just change the default status on BuildResult itself, rather than here.

xokdvium · 2026-02-06T21:55:48Z

src/libstore/include/nix/store/build-result.hh

+    /// Goal was never attempted because another goal failed (and
+    /// `--keep-going` wasn't used). Requires the
+    /// `cancelled-and-hash-mismatch-status` feature; falls back to
+    /// `MiscFailure` when communicating with older remotes.
+    Cancelled,


This should also handle Interrupted cases right?

Honestly I am not sure, I asked @amaanq to roll in @edolstra's PR because I didn't want us to do two separate feature flags back to back.

Comment might just be wrong.

I added the comment based on Eelco's PR description, I don't think handling Interrupted would make sense since it's not a BuildResult status but rather its own error that occurs on SIGINT, SIGTERM, and SIGHUP.

src/libstore/build-result.cc

Ericson2314 · 2026-03-03T01:43:10Z

I think this is pretty good, what needs to happen next is that the build trace rework docs release (which should perhaps be renamed?) is updated again to cover these protocol changes in addition to the others.

This commit adds a `cancelled-and-hash-mismatch-status` protocol feature that gates two new `BuildResult` failure statuses: `HashMismatch` (a specific type of `OutputRejected` for hash mismatches) and `Cancelled` (for goals never attempted because another goal failed without `--keep-going`). Goals now default to `Cancelled` status instead of `MiscFailure`. When communicating with older remotes, `HashMismatch` falls back to `OutputRejected` and `Cancelled` falls back to `MiscFailure`. Co-authored-by: Eelco Dolstra <edolstra@gmail.com>

github-actions bot added new-cli Relating to the "nix" command with-tests Issues related to testing. PRs with tests have some priority store Issues and pull requests concerning the Nix store c api Nix as a C library with a stable interface labels Jan 26, 2026

amaanq force-pushed the hash-mismatch-fix branch 2 times, most recently from 7c26fed to 145c623 Compare January 29, 2026 01:24

Ericson2314 marked this pull request as ready for review January 29, 2026 14:36

Ericson2314 requested review from Ericson2314 and edolstra as code owners January 29, 2026 14:36