Addresses the PR #103 round-3 review: length-delta verification is
defeated by an intercept that rewrites an op to a DIFFERENT
equal-length range, and "replacement text appears at start" is defeated
by one that enlarges `end` by a byte.
The buffer mutators (buf:insert/delete/replace) now RETURN the
effective edit — `(start, end, inserted_len)` of the post-intercept
operation actually applied (they returned nothing before, so no caller
breaks). killring compares those against what it requested:
- C-k / cut: any deviation (shifted range, resized range, nonzero
insertion) means the bytes removed are not the bytes sliced — the
ring and OS clipboard receive nothing, the chain clears, and the
interceptor's result stands. cut now goes through buf:delete (for
the effective edit) with explicit clear_selection + goto_byte.
- M-y: any deviation from (s.start, s.stop, #entry.text) drops the
session — including the end+1 enlargement that silently deleted an
extra byte while passing the old text-at-start check. The redundant
post-replace slice verify is gone; the exact contract replaces it.
Tests (kill_ring_acceptance now 30):
equal_length_shifted_delete_does_not_feed_the_ring (delete shifted +2,
same length — the case a length delta cannot see),
stop_enlarging_replace_ends_the_yank_session (mid-buffer yank so the
enlarged range is valid and the transform path — not range validation —
is what fires; at buffer end the same intercept fails validation and
takes the rejection path, which also drops the session).
Gates: fmt + workspace clippy clean; lib 1500; crdt 1672; killring 30;
cua 5; m6_4/m6_5 repl (mutator-heavy) 15/11; git diff --check clean.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Levi Neuwirth
8da143b402