A component whose :main-instance-id points to a missing shape fails
validation on its copies with :ref-shape-not-found. A repair scoped to
the copy's page never sees the main's own error, so it detached the
copy, even when the main was still on the component's page.
The repair of :ref-shape-not-found now looks for the component's main
on its page first and points :main-instance-id back to it, which keeps
the copy linked. A copy is still detached when no main is found.
A save whose changes failed validation was rejected as a whole: autosave
stopped, the edits made after it piled up unsent, and a reload lost
them all, the valid ones included.
The frontend now sends each commit of a save as its own group with its
commit id (:changes-with-metadata). When applying and validating all of
them at once fails, the backend searches by bisection for the first
commit that fails, keeps the commits before it and answers with
:rejected (that commit and every later one). Only the kept changes are
stored, snapshotted and broadcast, so other users never see the rejected
ones. Flat :changes and groups without ids stay all-or-nothing; database
and network errors still fail the whole request. A rejection without an
error type is reported as an internal error.
The frontend rolls the file back to what the server holds: it undoes
every pending commit of that file, applies again the remote changes that
arrived meanwhile, and redoes the kept commits. Undoing only the
rejected commits would write stale values over a peer's later change to
the same attribute. The rejected and later commits leave the queue, the
buffer and the undo history, and a warning that hides after ten seconds
tells the user. The pure bookkeeping lives in
app.main.data.persistence.commits.
The pending notice of a commit the rollback dropped no longer leaves the
save status at pending, which made "Pin this version" hang and fail.
Debug tools drive these cases by hand: debug.commitInvalidChange() makes a
save fail validation, holdSaves() delays the answers, failNextSave() and
failNextRollback() fail them on purpose (backend flag debug-save-faults),
and persistenceState() shows the queue.
