fd1210e557
Complete task002 through task016 across cache correctness, editor lifecycle, C boundaries, build and release governance, dictionary provenance, performance, interactive workflows, tests, documentation, and final cleanup.
2.1 KiB
Serialize a Logical Copy Instead of Restoring After Save
Context
EKP previously unformatted the display buffer in before-save-hook and
reformatted it in after-save-hook. Emacs does not run after-save-hook
when writing fails or is interrupted, so the screen stayed unformatted and
the marker state stayed live.
Decision
Do not mutate the source buffer during save. A buffer-local
write-region-annotate-functions entry switches whole-buffer writes to a
hidden logical copy. This is the same documented buffer-switch boundary used
by Emacs format encoders, so normal backup, coding, file-mode, VC, and later
annotation behavior remains owned by Emacs.
Alternatives Rejected
Add another restoration hook
There is no general failure hook paired with after-save-hook. A
post-command fallback would miss programmatic saves and nested calls.
Advise save-buffer or write-region globally
Global advice would make every Emacs save share EKP's lifecycle and create ordering conflicts with other packages.
Reimplement saving in write-contents-functions
Owning the actual write would duplicate backup, coding, file modes, VC, and visited-file semantics that Emacs already implements.
Consequences
- Success and failure paths leave the visible layout byte-identical.
- Disk and auto-save output receive logical text.
- A successful write disposes the copy immediately.
- Because Emacs does not call the post-annotation function after a failed write, at most one hidden copy remains per source buffer; retry or teardown replaces and clears it.
- No global advice, external dependency, or saved-file format changed.
Verification
The old model failed real missing-directory and forced-quit tests by leaving the logical text visible. The new model passes success, filesystem failure, encoding failure plus retry, and interruption tests. Full ERT passes 102/102, C/Elisp fuzz passes 300/300, and warnings-as-errors byte compilation plus checkdoc are clean.
Rollback
Restore the before/after hooks and their marker state. Existing files need no migration because both designs write the same logical bytes.