Timeline

parseIdentity refused an identity carrying an empty address twice over, once as `open + 1 == close` and again as `email.len == 0`. That is not malformed input. Setting `user.email` to the empty string is ordinary git configuration; `git fast-export` writes the identity with an empty angle-bracket pair, and `git fast-import` reads that same stream back to the same commit. The construct is valid by git's own definition on both sides of its own tooling, and we rejected it.

The cost was not cosmetic. Two such commits, reachable only through a merge's second parent, aborted the import of an entire 437 commit repository with `import-git: import failed: Malformed`, naming neither the line nor the rule.

Only the email clauses are relaxed. The name clauses stay: git's own porcelain refuses an empty ident name, and the importer maps the identity's name onto the U card login, so a nameless identity would produce a nameless check-in. The two questions were conflated in a single condition, which is a large part of why this went unnoticed, so the guard now separates them and says why.

This is the third defect on this branch of the same shape: a property of our own fixtures promoted into a rule about the world. The first two were bounds tuned to the width of our benchmark corpus. This one is sharper, a refusal of input the tool we integrate with emits by default. Every identity fixture in the parser tests carried a non-empty email, so a uniform corpus could not falsify a rule that keys on emptiness.

Both tests are witnesses rather than decoration: each fails with Malformed against the previous parser and passes against this one. The unit test pins the construct and the empty-name refusal beside it; the differential test has git itself produce the commit and then asserts the imported check-in carries the login mohye77 rather than an empty user. check-in: 1f21f96558 user: dmestas tags: sub-manifest

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