| Comment: | submanifest: incremental apply must equal canonical construction
The incremental tree editor diverged from buildTree on realistic filename distributions. OldTreeCursor.appendPrefixAtHeight read the retained native-prefix list without consuming it, so one descriptor could be spliced into two different output levels: buildUnpublished placed the height-1 prefixes into the leaves, and mergeRootPrefixes then prepended the identical descriptor again before finishRootLevel. The emitted interior node carried the same S key twice, which fails artifact.parse's ascending-S guard, so an import aborted partway through a real history with a SyntaxError raised by our own grammar. finishCheckpoint already guarded its own splice with a height test. That guard was an ad-hoc workaround for this same double-append, and mergeRootPrefixes never had one. The splice now consumes what it emits, so a retained descriptor lands in exactly one level and the guard becomes unnecessary rather than duplicated. Found by importing marktext, not by the suite. Every name corpus here was uniform, and a duplicated prefix descriptor requires names that share prefixes at differing depths, so 55 tests could pass over a defect that breaks real repositories. The new seeded differential sweep generates four corpora of 136 to 240 paths with mixed depth, shared directories, dotfiles and 1 to 43 byte basenames, over every supported k with twelve batches each, and asserts it reached a tree at least three levels deep so it cannot quietly degrade into testing flat roots. It diverges in 20 of 452 batches against the unfixed editor, every divergence unparseable. The decoded-root validation memo lands alongside it: repeated lookupTree validation against an unchanged root is answered once instead of rebuilt, which takes this file's own 56 tests from 1701 to 450 seconds over identical assertions. |
|---|---|
| Timelines: | family | ancestors | descendants | both | sub-manifest |
| Files: | files | file ages | folders |
| SHA3-256: |
4a95e436afff1cc037dca4d9bab4aafe |
| User & Date: | dmestas on 2026-07-31 02:39:50.470 |
| Other Links: | branch diff | manifest | tags |
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2026-07-31
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| 02:56 |
git-import: translate a Git fast-export stream into a zit history
`zit import-git SOURCE DEST` reads a Git repository through `git fast- export` and builds a zit repository from it. The destination appears only after the export, artifact creation and publication have all completed, so a failure anywhere leaves no half-published repository behind; this is the first caller of the logstore artifact batch added earlier on this branch, which is what makes a check-in's blobs arrive as a unit. Mode 160000 now parses as a gitlink instead of error.UnsupportedMode. That completes the split begun in the previous check-in: reporting what the stream said is the parser's job, and deciding that zit has no submodule concept is the importer's. The refusal still happens, but it now explains itself instead of failing as a parse error on input git legitimately emits. Signed commits are refused by default rather than imported with the signature silently dropped. Fossil has no signature card, so importing one is a loss the operator should choose; --drop-signatures accepts it explicitly. The sub-manifest parameter is analyzed, not guessed. Preflight measures the source's own name set and pins its measured optimum, and --submanifest-k overrides that only to match another repository's existing pin, which is what lets two repositories share sub-manifests by content address. On a 100,000 file corpus the analyzed value cuts the objective by roughly 3.4x against the fixed default it replaces. Correctness is checked differentially against real Git rather than against fixtures we wrote: every materialized tree is compared to `git ls-tree` for the corresponding commit, refs and annotated tags are compared to the source, and both comparators now assert that a gitlink is absent rather than merely tolerating it, so the omission is a contract instead of an accident. The rest is wiring. extras learns the import provenance names, root.zig exports the importer modules across the executable and library boundary, tidy and the CI step guard learn the new test roots and build steps, and the e2e help check learns that a verb spelled import_git in Zig is import-git on the command line. check-in: dc0aa2f858 user: dmestas tags: sub-manifest | |
| 02:39 |
submanifest: incremental apply must equal canonical construction
The incremental tree editor diverged from buildTree on realistic filename distributions. OldTreeCursor.appendPrefixAtHeight read the retained native-prefix list without consuming it, so one descriptor could be spliced into two different output levels: buildUnpublished placed the height-1 prefixes into the leaves, and mergeRootPrefixes then prepended the identical descriptor again before finishRootLevel. The emitted interior node carried the same S key twice, which fails artifact.parse's ascending-S guard, so an import aborted partway through a real history with a SyntaxError raised by our own grammar. finishCheckpoint already guarded its own splice with a height test. That guard was an ad-hoc workaround for this same double-append, and mergeRootPrefixes never had one. The splice now consumes what it emits, so a retained descriptor lands in exactly one level and the guard becomes unnecessary rather than duplicated. Found by importing marktext, not by the suite. Every name corpus here was uniform, and a duplicated prefix descriptor requires names that share prefixes at differing depths, so 55 tests could pass over a defect that breaks real repositories. The new seeded differential sweep generates four corpora of 136 to 240 paths with mixed depth, shared directories, dotfiles and 1 to 43 byte basenames, over every supported k with twelve batches each, and asserts it reached a tree at least three levels deep so it cannot quietly degrade into testing flat roots. It diverges in 20 of 452 batches against the unfixed editor, every divergence unparseable. The decoded-root validation memo lands alongside it: repeated lookupTree validation against an unchanged root is answered once instead of rebuilt, which takes this file's own 56 tests from 1701 to 450 seconds over identical assertions. check-in: 4a95e436af user: dmestas tags: sub-manifest | |
| 02:28 |
fast-export: derive the per-commit file-command ceiling
Limits.max_file_commands_per_commit was a standalone number, and the caller pinned it to the width of our own benchmark corpus. That is a fixture size promoted to policy: no headroom, no way to raise it without a rebuild, and it refused legitimate histories. `git fast-export` lists an entire tree for a root commit and for any commit whose first parent was not exported, so the ceiling is reached by ordinary repositories whose initial commit lands a whole codebase at once. The bound itself is necessary. admitData is the parser's only byte admission and it sees the byte count in a `data` header alone; every file command additionally allocates a list slot and a duplicated path into the per- commit arena with nothing charging for them, so the command loop is otherwise unbounded against a subprocess pipe. It is now computed: fileCommandCeiling(limits) = max_total_data divided by min_retained_bytes_per_file_command, where that constant is @sizeOf(FileCommand) plus one -- a command's list slot plus the shortest path it can carry, the empty path being rejected. Nothing smaller is representable, which is what makes it safe to divide a byte budget by. The ceiling restates the arena authorization the caller already granted, in commands rather than bytes, and moves when that authorization moves. Refusal retains the observed count, the ceiling, and the budget that produced it, so the diagnostic names all three rather than only its own error. The remaining limits gain distinct names -- Data, Event, FileCommand, Line, Merge and Path -- in place of one LimitExceeded that could not say which bound was hit. Exact-count data may carry an optional trailing LF, so only the first following empty line is ambiguous with the commit terminator; readDataExact and readCommitData split that decision instead of guessing. check-in: 85d510d361 user: dmestas tags: sub-manifest | |