Álvaro Tejero Cantero 5cb615ea88
🐛 Stop an update from main discarding a diverged branch's own work
Data loss, reproduced twice rather than inferred. A branch stores no
data of its own, so its whole work lives in `file_branch_change`, and
`update-branch-from-main` had a fast path that deleted every one of
those rows whenever the update found nothing of main's to apply. The
comment there assumed the branch was in sync with main, which holds only
when the branch has no changes of its own, and `branch-diverged?` was
already computed two lines above and consulted only inside
`reposition-base!`.

A branch with one fill edit of `#bb0000` and an untouched main, updated
with no resolutions, returned `:updated` and came back `#000000` with an
empty log. The user asked to catch up with a main that had not moved and
lost their edit. Through the modal the same defect made the resolution
that says "keep mine" the one that discards it.

The fast path is now guarded by `(not branch-diverged?)`, so a diverged
branch falls through to the squash that re-derives its net against the
new base. The predicate is the right one: it compares the branch file's
own revision counter against the revision the base was last positioned
at, and a log row and a revision bump are one event, because
`persist-branch-file!` is the log's only appender. The comment at the
guard states the invariant, which is that the log may be emptied only
when what it encodes already sits in the base.

One correction to how the fast path was described while this was being
chased: `(empty? changes)` does not mean the branch has nothing of its
own. In the update direction the change set is MAIN's contribution, so a
branch that is behind main in content already took the squash path and
still does. The fast path is reached when main has nothing to contribute,
which is what the third new test pins.

The three sibling paths that also empty or replace a log were each
judged and are sound, because each one writes the state elsewhere inside
the same transaction before emptying.

Three regression tests, one per reproduction plus the case the fast path
exists for, asserting through the derived document rather than through
log row counts, because a legitimate squash rewrites the log while
preserving the state.

Verified: the whole backend suite, 923 tests and 5,550 assertions with 0
failures. The two live demo branches were checked read-only and still
hold their one op-log row each, so the hand-test fixture was never
damaged.
2026-10-06 10:36:55 +02:00
2026-09-25 11:11:44 +02:00
2026-09-23 18:53:25 +02:00
2021-11-15 09:54:36 -05:00
2026-09-29 09:07:34 +02:00
2026-09-29 09:07:34 +02:00
2020-08-11 10:11:23 +02:00
2025-01-22 15:46:23 +01:00
2026-07-22 14:18:51 +02:00
2017-03-06 18:42:58 +01:00
2026-09-22 10:22:31 +02:00
2025-06-02 12:09:20 +02:00
2023-11-15 10:55:39 +01:00
2026-06-09 18:48:03 +02:00
2020-08-05 11:19:34 +02:00

Verified DPG Penpot Community Managed with Taiga.io Gitpod ready-to-code

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Penpot is the open-source design platform for teams that build digital products at scale.

Penpot’s key strength lies in giving you full ownership of your design infrastructure. Built on open source and designed for self-hosting, it puts teams in complete control of their design environment supporting strict compliance and governance requirements. Whether used in the browser or deployed on your own servers, Penpot works with open standards like SVG, CSS, HTML, and JSON.

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Why Penpot

Penpot connects design, code, and AI workflows through a code-based approach, making designs readable by developers and AI via the MCP server. This approach helps teams ship what’s actually designed and manage design systems at scale with powerful design tokens. As a self-hosted, open-source and real-time collaboration platform, Penpot offers full flexibility, security, and ownership without vendor lock-in. Learn more about why Penpot is the platform for your team.

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Penpot: The open-source design tool for design and code collaboration
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