fix(sidebar): restore closed state and a usable width on launch

[eugenioenko]

Why

Two related bugs in how the sidebar is restored on launch:

1. A closed sidebar reopened. Visibility was never persisted; startup showed the sidebar whenever the workspace had folders.
2. It reopened 1 to 2 columns wide after a drag-close. Dragging the divider closed persisted every intermediate width (5, 4, 3, 2, 1); the final 0 hides the sidebar but left the last tiny width in state.json. Startup restored any width > 0, bypassing the MinSidebarWidth (now 15, raised from 10) check that only ShowSidebar applies. This predates refactor(config): separate session state from user settings #665, which carried the same logic from settings.json to state.json.

Change

• Dragging the divider no longer writes state.json on every mouse move. The split panel reports OnResizeEnd when a drag is released or canceled; the sidebar resizes live and its width and visibility are saved once at the end. Show, hide, and the Increase/Decrease Sidebar Width commands share the same save path, so those commands now persist the width too.
• The Changes panel commit history divider gets the same treatment: ContentSplitWidget reports OnResizeEnd, and the height is saved once on release instead of on every mouse move.
• state.json gains sidebarHidden, written when the user hides or shows the sidebar (toggle, drag, or any command that opens it) and honored at startup.
• The welcome empty state hides the sidebar without persisting, so a folderless launch doesn't hide it for the next session with folders.
• Saving skips widths below MinSidebarWidth, so the last usable width survives a drag-close.
• Startup ignores restored widths below MinSidebarWidth (state.json or the settings.json fallback) and uses the default, so existing bad state files recover.

Tests

TestSidebarDragPersistsOnlyOnRelease (e2e, real mouse events): nothing is saved mid-drag, and releasing saves the hidden state after a drag-close and the new width after a drag-open. It fails on the previous per-move saving.

TestCommitHistoryDragPersistsOnlyOnRelease (e2e): the same contract for the commit history divider, also failing on the previous code.

Unit tests in internal/app, both failing without the fix:

• TestSidebarClosedStateRestores: closing persists across a rebuild, reopening persists, and the empty-state hide does not persist.
• TestSidebarDraggedClosedRestoresUsableWidth: dragging to 0 keeps the last usable width, and a saved width of 2 restores to the default.

Exercised in the real binary with an isolated TTT_CONFIG_DIR:

• Toggle closed, quit: state.json = {"sidebarHidden":true}, and the next launch starts with the sidebar closed:

    File   Edit   Selection   View   Options   Help
   ╭──────────╮
   │ untitled │
  

• Toggle open, quit: the flag is cleared, and the next launch shows the sidebar.
• Drag to 19 columns, then drag closed: state.json = {"sidebarWidth":19,"sidebarHidden":true} (the width before the drag, not one passed through on the way).
• Dragging the commit history divider up 5 rows saves {"commitHistoryHeight":17} once, and the next launch restores it.
• {"sidebarWidth":2} launches at the default width of 30.

make test passes. make lint reports 6 staticcheck SA5011 issues in unrelated test files; they are also on main.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Improvements
  • Sidebar visibility is now restored between sessions when changed by the user.
  • The sidebar no longer stays hidden in later sessions just because the workspace was empty.
  • Sidebar widths below the minimum are ignored, and saved widths below the minimum restore to the default.

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⚙️ Run configuration

Configuration used: Repository: eugenioenko/ttt/.coderabbit.yaml

Review profile: CHILL

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Run ID: b71b9d30-0ed8-40ed-8b8c-f7a12b95ddd5

📥 Commits

Reviewing files that changed from the base of the PR and between 832c90e and 2a99a37.

📒 Files selected for processing (7)

• internal/app/app.go
• internal/app/callbacks.go
• internal/app/changes_panel.go
• internal/app/settings_apply_test.go
• internal/ui/content_split.go
• internal/ui/split_panel.go
• tests/e2e/sidebar_drag_persist_test.go

📝 Walkthrough

Walkthrough

Sidebar visibility now persists across app rebuilds. Hiding the sidebar for the empty state does not save a hidden preference. Saved and configured sidebar widths below the minimum are ignored, and narrow divider positions are not saved.

Changes

Sidebar State and Width

Layer / File(s)	Summary
Persist sidebar visibility internal/config/state.go, internal/app/app.go, internal/app/widgets.go, internal/app/welcome.go, internal/app/settings_apply_test.go	Sidebar visibility is saved when it changes and restored across app rebuilds. Empty-state hiding does not persist a hidden preference.
Apply minimum sidebar width internal/ui/split_panel.go, internal/app/app.go, internal/app/widgets.go, internal/app/settings_apply_test.go	Saved and configured widths below the minimum do not override the usable width. Persistence skips divider positions below the minimum. Tests cover narrow divider and saved widths.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: arimxyer, simonocampo1

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 6 functions across 6 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main changes: restoring the sidebar's closed state and preventing unusable widths at launch.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
In @internal/app/widgets.go:
- Around line 307-310: In refreshWorkspaceWidgets, guard the automatic
ShowSidebar call in the wasEmpty branch so opening the first folder preserves
State.SidebarHidden when it is true. Leave explicit sidebar actions unchanged.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository: eugenioenko/ttt/.coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: a62abc86-ec42-47c1-bc15-71262959f9f8

📥 Commits

Reviewing files that changed from the base of the PR and between 7f32fb2 and 832c90e.

📒 Files selected for processing (6)

• internal/app/app.go
• internal/app/settings_apply_test.go
• internal/app/welcome.go
• internal/app/widgets.go
• internal/config/state.go
• internal/ui/split_panel.go

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