Preserve point and evil visual markers across redraws#164
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dakra merged 2 commits intodakra:mainfrom Apr 21, 2026
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Full and partial redraw paths both destroy markers:
- Full: `env.eraseBuffer()' snaps every marker to `point-min'.
- Partial: `env.deleteRegion' + `env.insert' per dirty row drift
markers asymmetrically by insertion-type, random-walking them
away from the user's intended position.
Point is owned by the renderer (placed at the TUI cursor on exit),
but `mark' is user state — `C-SPC' in an emacs-state buffer, any
region command in normal-state — and must survive.
Snapshot `(mark-marker)` position at the top of `redraw' and
restore it on exit via `defer'. Clamp to `point-max' in case the
buffer shrank. No change when the mark was never set in the buffer
(`marker-position' returns nil).
Other markers (e.g. evil's `evil-visual-beginning' /
`evil-visual-end') stay the caller's concern — a package can wrap
`ghostel--redraw' with its own save/restore for state the native
module cannot know about.
Adds `mark-marker' / `marker-position' / `set-marker' to the
symbol cache and thin `Env' helpers. One ERT case verifying mark
survives a full-redraw cycle.
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`evil-ghostel--around-redraw' used to save and restore only `point', and only in non-insert/emacs states. Native `ghostel--redraw' rewrites the viewport region on every call, moving every marker in the buffer — `evil-visual-beginning' and `evil-visual-end' drift asymmetrically by insertion-type, so `v' in a buffer with a streaming TUI (Claude Code, watch, streaming logs) shows a multi-row selection the moment `v' is pressed: mark had drifted backwards and `evil-visual-end' ratcheted forward while the user was idle in the buffer. Extend the advice to save and restore: - `point' in non-terminal states (unchanged). - `evil-visual-beginning' and `evil-visual-end' in `visual' state. `mark' is preserved by `ghostel--redraw' itself (see PR dakra#163 — the native-side fix lives in `src/render.zig', where all users benefit regardless of whether evil-ghostel is loaded). This PR layers on top of that — it can be merged after or before dakra#163; if merged first, `mark' stays drifting until the native patch lands. Tests: three mock-based cases covering point preservation in normal, point follow-through in emacs, and visual-marker preservation in visual.
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Problem
evil-ghostel--around-redraw' currently saves and restores onlypoint', and only in non-insert/emacs states. Nativeghostel--redraw' rewrites the viewport region on every call, moving every marker in the buffer.evil-visual-beginning' /evil-visual-end' drift asymmetrically by insertion-type — sov' pressed in a buffer being updated by a streaming TUI (Claude Code, `watch', streaming logs) produces a multi-row selection instead of one char: both markers had already drifted apart while the user was idle in the buffer.Change
Extend the advice to save and restore, in addition to point:
evil-visual-beginning' andevil-visual-end' in `visual' state.insert' andemacs' continue to let point follow the TUI cursor. Alt-screen guard unchanged.Relationship to #163
Layered on top of the native
mark'-preservation PR (#163). Deliberately does **not** handlemark' here — it's universal buffer state and belongs at the native layer where all users benefit regardless of whether evil-ghostel is loaded. The layering is:markacross native redraws #163): `mark' — single buffer-local marker every Emacs package depends on.point' in normal/visual,evil-visual-beginning' / `evil-visual-end' — evil-specific state the native module can't know about.Order-independent: if this merges first, `mark' stays drifting until #163 lands; if #163 merges first, this closes the visual-marker gap. Both need to land for full coverage.
Tests
Three mock-based ERT cases: point preservation in normal, point follow-through in emacs, visual-marker preservation in visual.