Review finding 1 on PR #191. `notify_buffer_edit` clamped `cursor` and
`view_top` but not `win.selection.anchor`, and `rebuild_views_for` had
the same gap. Clamping the cursor is not enough to make the region safe:
`Window::region` orders `(anchor, cursor)`, so a stale anchor above a
clamped cursor is still the region's high end and `region_bytes` slices
the rope with it. Reproduced before the fix as
`assertion failed: end <= self.len()` at `src/rope.rs:145`, reached from
`EditorCore::clipboard_copy` after a generated rewrite.
The anchor is DROPPED, not clamped. A window must always have a cursor,
so clamping one is the only available answer; a window need not have a
selection, and a clamped anchor asserts a region boundary the user never
placed --- after a wholesale rewrite the surviving offsets address
unrelated bytes. This is not a new rule: `window.quit`'s restore already
answers the same question the same way with
`selection.filter(|sel| sel.anchor <= len)` (`src/editor_core.rs:3259`).
One rule, now three call sites.
Both exits are pinned separately, because fixing one and trusting the
other is how the gap arose: `acc16h` drives `notify_buffer_edit` through
a generated write, `acc16i` drives `rebuild_views_for` through
`pmacs.help.show_command`, which is the `*help*` renderer's real path.
Deleting either call site fails only its own test. The pin also
discriminates DROP from CLAMP, because that is the decision a revised
Q#GB6 could overturn.
The wording is marked PROVISIONAL in both the implementation and the
pins. The rule belongs to Q#GB6, and PR #188's approved revision 5 does
not mention the anchor; a revision request carrying this defect is with
that lane. If the landed revision says clamp or translate, this changes
to match rather than standing as a third description.
Also in this commit, review findings 2 and 3 --- the tree asserting what
the record does not support:
- Criterion 5's restatement is withdrawn in BOTH suites. The tests now
quote the approved criterion, are renamed `*_provisional_*`, and say
they do not satisfy it; the evidence (`ensure_writable` precedes the
intercept chain, with the measured `ReadOnly` message) is recorded as
what was sent to #188, not as a replacement contract. The framing's
own bite is unchanged and still fails them.
- Criterion 7's "for each adopter" is restored: the listview half now
exists as its own test. Its inability to carry the framing's mutation
bite --- `window.switch_buffer` rebuilds the `TextView`, verified by
applying the mutation and watching this half stay green while the
dired half fails --- is recorded in the test and filed with #188,
not resolved here.
- Criteria 11 and 12 are relabelled from `main` bites to mutation bites.
Both fail on `main` only at their disambiguation premise and never
reach the assertions they exist for, so a revert is not evidence for
what they assert.
How a restated contract passed the previous gate run, since the next
lane can use this: nothing in the gate suite reads a framing document,
so a test that quietly narrows its criterion is indistinguishable from
one that satisfies it --- both are green, and `scripts/bite` only proves
an assertion bites some pre-image, never that the assertion is the one
that was approved. The gate can catch a test that does not bite; it
cannot catch a test that bites the wrong contract, so that check has to
happen where the criterion is read.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lv428Fth9LRtffwJSsqH7T
Levi Neuwirth
4da4830f80