[gavin-jeong]

JIRA: https://sendbird.atlassian.net/browse/CPLAT-12912

What

tuikit goes from c19aa4f to 5b7fabe, which adds the split package (keyolk/tuikit#11). ccx resized its panes three ways: [ ] ±5 (15-85), a mouse drag that grabbed a cell of each pane (20-80), and set:ratio N; the config and plugins views clamped to 20-80 on their own. All of them now go through one split.Model on App, shared by the sessions, conversation, config and plugins splits, as the old splitRatio was.

This branch starts from master and does not depend on #180.

The split

	Before	After
Ratio	splitRatio int percent	split.Model: fraction 0.15-0.85, default 0.35, step 0.05
Minimums	list ≥ 30 (ListWidth), preview ≥ 20 (adjustSplitRatio only)	MinA: 30, MinB: 20, enforced on every write and every layout
Widths	ListWidth/PreviewWidth arithmetic, plus ~20 copies of width - list - 1	SplitPane.layout → split.Model.Layout; ListWidth/PreviewWidth read it
Divider	raw ANSI │	DrawDivider: │, heavy ┃ while dragging (visible under NO_COLOR)
Narrow	list alone under 40 columns or 10 rows	same rules (Collapse: 40, minSplitHeight); a width that cannot fit 30 + 1 + 20 also shows the list alone, full width

SplitPane.layout is the only source of widths: Render, renderSessionSplit, the drag-selection panes (splitRects) and the click/wheel hit tests (inPreview) all read the same rects.

Mouse

• handleSplitMouse runs first in handleMouse, before selection, overlays and clicks. A press on the divider starts a drag and is consumed; motion moves the divider; release ends it. A double click on the divider resets it.
• tryStartDragResize, handleDragResize, the dragResizing field and its guard in handleSelectionMouse are removed.
• The old grab zone (±1 cell into each pane) is not kept (Grab: 0). Those cells belong to the panes, so a drag that starts there selects text. TestDragNextToDividerResizesInsteadOfSelecting asserted the opposite and is now TestDragNextToDividerSelectsInsteadOfResizing.
• While an overlay or copy mode owns the mouse, or the preview is closed or zoomed, the split gets an empty area: it never takes a press, and a drag already in progress still ends on release.

Keys

Key	Action	Where
< / >	shrink / grow the list	every split view (new: session.split_shrink, session.split_grow)
=	reset to 35%	every split view (new: session.split_reset)
[ / ]	shrink / grow (kept as aliases)	only where they already resized; config page cycling and inspector facet cycling are unchanged

• The defaults come from split.Bindings. keys.Conflicts stays clean, and no other binding in any scope uses <, > or =, so nothing was rebound.
• At a bound, </> show "Split at its limit" instead of doing nothing silently.
• Footer: <>= resize, last in priority, where []:resize was. ? overlay: a < / > / = row in the sessions list, sessions preview, conversation, inspector, config and plugins help.
• set:ratio N is Set(N/100), clamped like any other write.

Saved state

• ui.json saves {"split": {"ratio": 0.4}}.
• split_ratio (a percentage) from an older ui.json or config.yaml is read once, in 15-85, and dropped on the next save. split.ratio wins when both are present.
• A ratio that is not a fraction (40, -1, 1.5) or an old percentage outside 15-85 keeps the default.
• Saving needs no new code: Update already calls saveUIState after every message and quit flushes.

Other

• restoreConvPreviewAnchor re-rendered the preview at a width computed from a fixed 50% ratio. It now re-renders at the width the preview is drawn at.
• hexToRGB was only used for the raw-ANSI divider and is removed.

Tests

Positions come from the rendered View(): the divider glyph left of the preview text, never the layout code. Persistence tests use withUIStateDir (HOME, XDG_CONFIG_HOME, XDG_STATE_HOME in t.TempDir()).

• TestSplitDividerDragMovesBoundaryEverywhere: press on the divider found in the frame, move, release. The divider shows heavy during the drag and moves in View. The list and preview selection panes match the new position. A click on old preview columns now focuses the list, and a click right of the new divider focuses the preview. Nothing selects.
• TestSplitPanePressStillSelects, TestDragNextToDividerSelectsInsteadOfResizing, TestSplitDoubleClickOnDividerResets.
• TestSplitKeysMoveDivider (>, <, =, ]), TestSplitClampHasNoDeadZone (40 × >, then one < moves at once, in both directions, minimums held), TestSplitKeysInConfigViewKeepPageCycling.
• TestSplitKeysShowInHelpAndFooter, TestSplitKeysDoNotShadowBindings.
• TestSplitKeysRewrapConversationPreview: after > and after a drag, the conversation preview shows every word, in order, none cut.
• TestSetRatioCommandIsAPercentOfTheSplit, TestSplitNarrowTerminal (60 and 80 columns fit, 45 columns shows the list alone at full width).
• TestSplitRatioSavedAndRestored, TestSplitGarbageInUIJSONFallsBackToDefault, TestSplitMigratesOldPercent (ui.json, config.yaml, new field wins).

Each new guard was checked with a compiling mutation, then restored:

Mutation	Failing test
split runs after selection	TestSplitDividerDragMovesBoundaryEverywhere, TestSplitDoubleClickOnDividerResets, TestDragOnSplitBorderStillResizes
selection panes laid out with the default ratio	TestSplitDividerDragMovesBoundaryEverywhere
click hit test laid out with the default ratio	TestSplitDividerDragMovesBoundaryEverywhere
no < / > arm	TestSplitKeysMoveDivider, TestSplitClampHasNoDeadZone
no = arm	TestSplitKeysMoveDivider
MinB 2 instead of 20	TestSplitClampHasNoDeadZone, TestSetRatioCommandIsAPercentOfTheSplit, TestSplitNarrowTerminal
divider never drawn heavy	TestSplitDividerDragMovesBoundaryEverywhere
split body without the title-row offset	TestDragPastPreviewBottomScrollsAndKeepsLines, TestDragInScrolledPreviewCopiesWhatIsShown
keys skip resizeAll	TestSplitKeysRewrapConversationPreview
footer hint without =	TestSplitKeysShowInHelpAndFooter
? row missing	TestSplitKeysShowInHelpAndFooter
split_reset default not from the kit	TestSplitKeysShowInHelpAndFooter
split.State not saved	TestSplitRatioSavedAndRestored, TestSplitMigratesOldPercent
split_ratio not migrated	TestSplitMigratesOldPercent
restore accepts any ratio	TestSplitGarbageInUIJSONFallsBackToDefault

Two mutations survive because they are equivalent in what the user sees:

• set:ratio clamping without the area: Layout clamps to the minimums when it draws, and the next key steps from the drawn position.
• Not resizing the active pane during a drag: Render and syncSessionSplitLayout re-size from the same layout on the next frame. The call stays, as the old drag code had it.

gofmt -l is clean. go vet ./... passes. go test ./..., go test -race ./... (one run) and env -u LC_ALL -u LC_CTYPE LANG=ko_KR.UTF-8 go test ./... all pass.

[upwind-code-us]

Upwind Code Scan - ✅ Passed

0 newly introduced vulnerabilities · 0 resolved · 2 total in this PR vs master

Total breakdown: 🔶 2 High

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Scan history (2 scans)

Commit	Scanned at	New	Resolved	Net
0de3d2e	2026-10-21 15:50 UTC	0	0	0
3f2895f <	2026-10-21 23:07 UTC	0	0	0

Last scanned: 3f2895f · 2026-10-21 23:07 UTC

[jinsekim]

LGTM!