ekp/CHANGELOG.md

Changelog

All notable changes to emacs-kp are documented here. The format follows Keep a Changelog, and the project aims to follow Semantic Versioning.

[Unreleased]

Fixed

• C-backed core layout and complete resize/reflow now reuse prepared paragraph, DP, and gap geometry and avoid duplicate projection publication. The four-round same-machine gate records p95 values of 27.687 ms and 27.487 ms respectively, with exact frozen-C/Elisp parity.
• Reprojecting a buffer now preserves the mark marker and mark-active independently. Showcase width keys and resize reflow no longer turn an old inactive mark into a highlighted region.
• The unfinished live line now keeps its source-edge whitespace natural. A leading/trailing space or tab appears in the same input turn, and whitespace exposed by backspace is no longer hidden by display "" until another glyph arrives.
• Enabling or disabling a theme, or changing a frame's default font, now invalidates live plan history and reflows every active auto-justify buffer with the new glyph metrics.
• Changing any Knuth-Plass cost parameter now selects a correctly keyed DP/render result immediately; cached paragraphs no longer require ekp-clear-caches. Structurally equal non-zero-looseness signatures now reuse their cached result instead of missing an eql cons key.
• Changing ekp-default-cws-stretch-pixel in automatic spacing mode now invalidates both paragraph-cache lookup paths immediately. Unchanged spacing signatures still reuse the cached paragraph.
• Buffer layout no longer rewrites the source character stream. Saving, region writes, direct Elisp reads, syntax, and search therefore operate on logical text without a temporary serialization copy.
• Live editing now separates committed projection from a local dirty edit transaction. Same-row typing performs no whole-hard-line planning, middle-row edits preserve unaffected break anchors, and exact source reversal restores the saved projection equal-including-properties.
• Point-only motion no longer changes live state or projection anywhere, including after leaving the active hard paragraph. Structural commits are owned by visual-row crossing, hard completion, the next real edit elsewhere, explicit refill, and width/font/layout-context changes.
• Kill/copy integration now composes with and restores an existing filter-buffer-substring-function, including DELETE operations, and strips only EKP-owned projection properties from copied text. Removing the final layout span outside auto mode restores the exact prior filter.
• Dictionary syntax no longer degrades silently: files containing libhyphen replacement/slash patterns fail with an explicit condition because the fixed-width DP cannot model their conditional rewrites.
• Mutating layout-relevant text properties on an already cached string now invalidates the same-string paragraph fast path. It reuses the complete structural cache key instead of a partial parallel signature.

Changed

• The core now exposes semantic ekp-layout-plan, ekp-layout-line, and ekp-layout-gap records. The compatible string renderer and the buffer renderer consume the same break, glue, indentation, and discretionary- hyphen decisions.
• Buffer/region layout is now a pure text-property projection on existing source characters: ASCII spaces combine space-width and absolute-pixel min-width; zero-source CJK/mixed glue uses min-width on a complete grapheme; indentation uses line-prefix; and visual breaks/hyphens use replacing display strings. EKP creates no overlay and inserts no layout character into a buffer.
• Auto-justify now uses stable hard-line transactions. A dirty island stays native between commit events, so ordinary keys neither run DP nor rewrite unrelated properties. Native visual-row crossing atomically republishes every completed row from the unchanged whole-hard-line core plan; the new row remains natural. A buffer-local 16-entry LRU reuses recent text/context plans, and common-prefix signatures minimize writes at commits. IME and resize publication remain generation-checked; no edit-idle or cursor-motion formatter exists.
• Auto-justify now owns its native soft-wrap precondition. It temporarily disables truncate-lines and narrow partial-window truncation, including Emacs's default sub-50-column behavior, then restores the prior values and buffer-local ownership on teardown.
• One buffer uses the narrowest displayed window as its authoritative width. Foreign replacing display owners and unsupported non-ASCII whitespace shrink keep only the affected hard paragraph natural and are reported by ekp-diagnose.
• Automatic work bounds a single hard paragraph with ekp-auto-justify-paragraph-limit (default 2,048 characters). Longer paragraphs remain naturally editable; ekp-refill-paragraph is the explicit unbounded quality pass.
• Breaking: the editor integration module is now ekp-buffer.el and provides ekp-buffer; replace (require 'ekp-region) with (require 'ekp-buffer). Module-owned configuration names now use the ekp-buffer- prefix. Public commands whose names describe an actual region or buffer operand are unchanged.
• The bundled dictionary inventory is now 49 reproducible entries with a pinned LibreOffice commit, per-file SHA-256/source/license manifest, and a portable verifier/exporter. Sanskrit was removed because the pinned upstream data has no authoritative license statement for that exact hyphenation file.
• Auto-justify mode now exposes its existing formatting, protection, and diagnostic commands in an EKP menu. Interactive no-break/verbatim changes report that their text properties last only for the current buffer session.

Tests

• ERT now covers source/tick/undo invariants, exact ASCII and CJK glue projection, display-only static breaks and hyphens, zero-projection underfilled input, whole-hard-line semantic-prefix selection, non-frozen earlier breaks, common-prefix differential writes, plan-cache reuse, point-motion projection stability, stable dirty transactions, exact reversible restoration, atomic visual-row commits, hard-paragraph completion, IME/stale generations, foreign ownership, narrowest-window policy, inactive/active mark preservation, immediate edge whitespace, consecutive spaces, newline/yank/real-undo paths, and the oversized-paragraph guard. GUI probes verify pixel widths. Reviewed temporal recordings verify width-key selection and immediate edge-whitespace states, plus stable middle-row edits, exact reversible restoration, atomic visual-row commits, zero-work point motion, public yank/undo, resize commits, and hard-paragraph completion without delayed snap or overlays.
• ERT fixtures now restore every mutable EKP option they isolate. The parshape C-bypass regression drives the public formatter, and reusable permuted-order plus per-test fresh-process runners prevent alphabetical execution from hiding leaked state.
• The GUI fit matrix now exits with status 1 when any row fails. A batch-safe forced-failure control locks the automation contract while the real seven-case matrix remains an explicitly loaded developer tool.
• Release invariants now have one local gate. CI action inputs are immutable, Windows runs the Elisp baseline, and the .phrase decision source is versionable instead of ignored.

Performance

• The live-path benchmark records append, historical-plan reuse, point-motion, and hard-boundary latency with plan/cache counters. At the synthetic 80-pixel width, same-row editing and point motion perform zero planning; point-motion p99 is 0.017 ms on C and 0.015 ms on Elisp. Across 291 appends, only 15 visual-row crossings invoke the planner. Those structural commits still exceed the 16 ms p99 frame budget on both backends and are tracked as issue018/task030; no stale reuse, debounce, skipped publication, or global GC workaround hides the miss.
• Tokenization now accumulates fragments and joins once per emitted box; dense hyphen insertion likewise joins original word slices once. On the 1,000–8,000-character adversarial benchmark, the 8,000-character cases improved from 3.133 s to 1.100 s and from 0.945 s to 0.013 s respectively.
• Cached “no hyphen” results now use an explicit miss sentinel, so repeated lookups do not rerun the dictionary computation.

Internal

• DP reuse identity, edge-space exclusion, and the lossless marker vocabulary now each have one directly tested rule owner. The consolidation removes formula/property-list drift without adding modules or hot-loop allocations.
• Final cleanup removed nine dead pass-through accessors and replaced direct use of Emacs's private substring-filter dispatcher with the public filter-buffer-substring path while preserving DELETE lifecycle ownership.
• The paragraph fast path no longer needs style-variable watchers: both the one-entry path and hash cache have one structural identity owner.

C module (1.6)

• The 15-field single and batch APIs now preflight vector shape, lengths, scalar types, and signed 32-bit input range before extraction. Caller errors signal ekp-c-invalid-input; allocation/no-result still returns nil. Enabled-backend signals are no longer swallowed by the Elisp dispatcher.
• Line metric, flexibility, and remaining-space intermediates are now 64-bit, eliminating signed overflow when valid int32 widths and protrusions combine.
• The default C build is portable (PROFILE=portable). Native CPU/LTO, debug, and sanitizer flags are explicit profiles, and ekp-c-module-build now passes argv directly to make from the module directory instead of interpolating a shell command.

[1.0.0] - 2026-07-27

First tagged release. Highlights of the work leading up to it:

Editor integration

• Saving an auto-justified buffer now writes the logical text to disk; soft line breaks, glue spaces and break hyphens are layout, not content, and no longer reach the file.
• isearch searches the logical text, so CJK phrases and hyphenated words are found across the justified layout.
• Copying/killing puts the logical text on the kill ring (via a buffer-local filter-buffer-substring-function).
• Justification no longer flips buffer-modified-p on an unmodified buffer — no stray lock files or auto-saves — and re-flow no longer fights undo.
• Text typed adjacent to synthesized glue/hyphens no longer inherits the marker properties (rear-nonsticky), so it is never mistaken for layout and deleted on the next re-flow.
• Switching major mode or turning the minor mode off restores the logical text cleanly, widening first so narrowing leaves no justified orphans.
• Paragraphs containing field/read-only text (comint prompts) are left verbatim.

New commands and options

• ekp-justify-buffer / ekp-unjustify-buffer.
• ekp-justify-region / ekp-unjustify-region act on the paragraph at point when no region is active (DWIM).
• ekp-org-setup / ekp-markdown-setup wire the verbatim-protection presets in one call; ekp-auto-justify-mode applies the matching one automatically in Org/Markdown buffers.
• fill-paragraph is remapped to ekp-refill-paragraph while the mode is on.
• User options are now defcustoms under the ekp / ekp-region groups.
• ekp-cjk-no-line-start-extra: Japanese line-start prohibition for small kana, the prolonged sound mark and iteration marks (JIS X 4051).
• ekp-auto-justify-tick-budget: time budget per background re-flow tick.

Typography

• First-line indent (ekp-first-line-indent) now runs on the fast 1D dynamic program and the C engine, instead of the heavy 2D path.
• Dictionary LEFTHYPHENMIN / RIGHTHYPHENMIN are honored (English now keeps ≥2 before and ≥3 after a break, per its dictionary).

Performance

• Session-global box-width cache eliminates cross-paragraph duplicate measurement (≈40% of string-pixel-width calls on the Chinese sample); byte-compiled justify of that sample dropped ~40%.
• Cache keys ignore volatile fontified bookkeeping, restoring the paragraph-cache hit rate in font-locked buffers.
• Large-buffer re-flow: huge edits chunk in the background, scrolled regions get priority, background ticks honor a time budget.

Fixed

• The DP cache no longer returns a stale layout after ekp-looseness changes (results are keyed by looseness).
• Changing a style variable (ekp-alignment, …) invalidates the same-string fast path.
• Missing dictionaries/ directory only disables hyphenation instead of breaking (require 'ekp).

C module (1.4 → 1.5)

• Breaking: the unused experimental C tokenization path (ekp-c-break-lines, ekp-c-hyphenate, ekp-c-load-hyphenator, ekp-c-set-spacing, and the ekp_paragraph.c / ekp_hyphen.c sources) is removed. It carried a heap overflow reachable from Lisp. Rebuild with make -C ekp_c clean all.
• ekp-c-break-with-arrays gains a 15th argument, FIRST-LINE-WIDTH, supporting first-line indent in C.
• Thread pool sized to the machine's cores, created lazily; a full queue blocks instead of dropping tasks.
• Allocation failures and bad arguments fail the call cleanly (Elisp fallback) instead of silently producing a different layout; extracted integers are clamped to int32.

Packaging

• Added COPYING (GPL-3.0-or-later) and license headers to all sources; real author/maintainer metadata.
• Autoload cookies on all interactive commands.
• Removed internal working files and an unused demo GIF from the repo.

Historical

Earlier work (the core KP overhaul and the P1/P2 typography wave — optimal line breaking, CJK kinsoku, hyphenation, pixel-exact justification, alignment modes, hanging punctuation, parshape, no-break atoms, verbatim protection, the C module) predates this changelog; see the git history.