zit 0.3.4

zit 0.3.4 is a crash fix. In 0.3.3 and earlier, zit info with no NAME segfaults on any repository whose history holds two check-ins with the same event.mtime — three merges landed within one millisecond is enough, and a repository that grows such a pair starts crashing without any change to zit. Every 0.3.3 install should take this.

The crash (zit#173)

The listing order's exact-mtime tiebreak compares full artifact hashes, and read them straight from the raw artifact store. Verbs on the zero-parse image path (.fast_read — bare info among them) carry the hashes in the image's own pool; their raw store is an empty placeholder, so the tie comparison read through an entry that was never populated. In a release build the only guard is a Debug assertion, which is compiled out: SIGSEGV. The same query under zit timeline opens the full derive and never crashes, which is what made the failure look random.

Five ordering tiebreaks had the same raw read — the timeline order, the tied-run micro-order, tied-name resolution, sync chain order, and the bisect span order. All five now read hashes through the backing-aware door, which answers from the image's pool on the image path and from the store on the full path. The order is unchanged on both.

Not hittable again

The empty placeholder store is gone. An image-backed state now carries a trap store: any raw store read under image backing panics immediately, in every build mode, naming the door to use — on any input, not only on a tie. The query-equivalence fixture now seeds an exact-mtime tied pair (and fails if the tie is ever lost from the fixture), and the .fast_read equivalence test compares the entire timeline ordering across both backings. Reintroducing the defect turns that test red with the named panic.

Also fixed while there: bare zit info ignored --no-cache; it honours it now.

Compatibility

• Artifacts, tags, and the sync protocol are unchanged; Fossil RFC revision 00 remains the target.
• No on-disk format changed (the image schema stays at version 6).
• No command, flag, or output changed, beyond info --no-cache now meaning what it says.

Qualification

zig build test, e2e, smoke (Fossil interop against a real fossil), muscle (41 differential steps), git-import-e2e, git-export-e2e, and dst, plus the three-runner CI battery (macOS ARM64, Linux x86-64, Linux ARM64). The fix was verified against the repository that first crashed: 0.3.3 exits with SIGSEGV on bare zit info there, 0.3.4 prints the checkout.