feat: autosave diff comments (#820)

Signed-off-by: Matt Toohey <contact@matttoohey.com>

Author: matt2e

apps/differ/src/App.svelte

@@ -96,6 +96,9 @@
   // ==========================================================================
 
   type DiffMode = 'all' | 'staged' | 'branch' | 'commit' | 'stack';
+  type DiffViewerHandle = {
+    flushCommentEditors: () => Promise<boolean>;
+  };
 
   let diffMode = $state<DiffMode>('all');
   let diffSpec = $state<DiffSpec>(commands.specUncommitted());
@@ -122,6 +125,7 @@
   let loading = $state(true);
   let loadingFile = $state<string | null>(null);
   let error = $state<string | null>(null);
+  let diffViewer = $state<DiffViewerHandle | null>(null);
 
   let localComments = $state<Comment[]>([]);
   let copiedFeedback = $state(false);
@@ -255,7 +259,21 @@
   // Diff mode switching
   // ==========================================================================
 
-  function setMode(mode: DiffMode, commit?: CommitInfo) {
+  async function flushCommentEditorsForDiffChange(): Promise<boolean> {
+    return (await diffViewer?.flushCommentEditors()) ?? true;
+  }
+
+  function resetDiffState() {
+    files = [];
+    diffCache = new Map();
+    selectedFile = null;
+    localComments = [];
+    error = null;
+  }
+
+  async function setMode(mode: DiffMode, commit?: CommitInfo): Promise<boolean> {
+    if (!(await flushCommentEditorsForDiffChange())) return false;
+
     showCommitPicker = false;
     showStackPicker = false;
     diffMode = mode;
@@ -299,26 +317,22 @@
         break;
     }
 
-    files = [];
-    diffCache = new Map();
-    selectedFile = null;
-    localComments = [];
-    error = null;
+    resetDiffState();
     loadDiff();
+    return true;
   }
 
-  function selectCommitBySha(sha: string) {
+  async function selectCommitBySha(sha: string): Promise<boolean> {
+    if (!(await flushCommentEditorsForDiffChange())) return false;
+
     diffMode = 'commit';
     diffSpec = commands.specCommit(sha);
     diffLabel = `Commit ${sha.slice(0, 7)}`;
     selectedCommit = null;
 
-    files = [];
-    diffCache = new Map();
-    selectedFile = null;
-    localComments = [];
-    error = null;
+    resetDiffState();
     loadDiff();
+    return true;
   }
 
   async function toggleCommitPicker() {
@@ -341,42 +355,42 @@
     showStackPicker = !showStackPicker;
   }
 
-  function selectStackBranch(branch: StackBranchInfo) {
+  async function selectStackBranch(branch: StackBranchInfo): Promise<boolean> {
+    if (!(await flushCommentEditorsForDiffChange())) return false;
+
     stackViewTarget = branch;
     diffSpec = commands.specStackBranch(branch.name, branch.parentRef);
     diffLabel = `Stack: ${branch.name.split('/').pop()}`;
     diffMode = 'stack';
     showStackPicker = false;
 
-    files = [];
-    diffCache = new Map();
-    selectedFile = null;
-    localComments = [];
-    error = null;
+    resetDiffState();
     loadDiff();
+    return true;
   }
 
-  function selectStackCommittedOnly() {
-    if (!stackInfo) return;
+  async function selectStackCommittedOnly(): Promise<boolean> {
+    if (!stackInfo) return false;
+    if (!(await flushCommentEditorsForDiffChange())) return false;
+
     stackViewTarget = null;
     diffSpec = commands.specStackCommitted(stackInfo.parentBranch);
     diffLabel = `Stack vs ${stackInfo.parentBranch.split('/').pop()} (committed)`;
     diffMode = 'stack';
     showStackPicker = false;
 
-    files = [];
-    diffCache = new Map();
-    selectedFile = null;
-    localComments = [];
-    error = null;
+    resetDiffState();
     loadDiff();
+    return true;
   }
 
   // ==========================================================================
   // Load diff
   // ==========================================================================
 
   async function loadDiff() {
+    if (!(await flushCommentEditorsForDiffChange())) return;
+
     loading = true;
     error = null;
     try {
@@ -394,7 +408,10 @@
     }
   }
 
-  async function selectFile(path: string | null) {
+  async function selectFile(path: string | null): Promise<boolean> {
+    if (path === selectedFile) return true;
+    if (!(await flushCommentEditorsForDiffChange())) return false;
+
     const thisGeneration = ++selectionGeneration;
 
     // Handle search-related behavior (expand and select first result)
@@ -408,7 +425,7 @@
       loadingFile = path;
       try {
         const diff = await commands.getFileDiff(diffSpec, path);
-        if (selectionGeneration !== thisGeneration) return;
+        if (selectionGeneration !== thisGeneration) return false;
         const newCache = new Map(diffCache);
         newCache.set(path, diff);
         diffCache = newCache;
@@ -418,6 +435,8 @@
         loadingFile = null;
       }
     }
+
+    return true;
   }
 
   // ==========================================================================
@@ -426,7 +445,11 @@
 
   let nextCommentId = 0;
 
-  async function handleAddComment(path: string, span: Span, content: string): Promise<void> {
+  async function handleAddComment(
+    path: string,
+    span: Span,
+    content: string
+  ): Promise<Comment | null> {
     const comment: Comment = {
       id: `local-${++nextCommentId}`,
       path,
@@ -443,6 +466,7 @@
       commitSessionId: null,
     };
     localComments = [...localComments, comment];
+    return comment;
   }
 
   async function handleUpdateComment(commentId: string, content: string): Promise<void> {
@@ -475,7 +499,7 @@
   // ==========================================================================
 
   function handleSelectFile(file: FileEntry) {
-    selectFile(file.path);
+    void selectFile(file.path);
   }
 
   // Load a file's diff without changing the selection (for search)
@@ -514,6 +538,8 @@
   // ==========================================================================
 
   async function handleFolderSelect(path: string) {
+    if (!(await flushCommentEditorsForDiffChange())) return;
+
     showFolderPicker = false;
     try {
       await commands.setRepoPath(path);
@@ -527,11 +553,7 @@
       diffMode = 'all';
       diffSpec = commands.specUncommitted();
       diffLabel = 'All Changes';
-      files = [];
-      diffCache = new Map();
-      selectedFile = null;
-      localComments = [];
-      error = null;
+      resetDiffState();
 
       // Fetch repo info without triggering a diff load yet —
       // we need to check for a Graphite stack first to avoid a race
@@ -543,7 +565,7 @@
       const si = await commands.getStackInfo();
       stackInfo = si;
       if (si) {
-        setMode('stack');
+        await setMode('stack');
       } else {
         loadDiff();
       }
@@ -602,7 +624,7 @@
     }
 
     // Select the file and scroll to the match
-    await selectFile(filePath);
+    if (!(await selectFile(filePath))) return;
     // Scroll to the specific line
     lineJumpToken += 1;
     jumpToLine = { lineIndex: match.lineIndex, token: lineJumpToken };
@@ -936,6 +958,7 @@
           </div>
         {:else}
           <DiffViewer
+            bind:this={diffViewer}
             diff={currentDiff}
             comments={localComments.filter((c) => c.path === selectedFile)}
             {jumpToLine}

apps/staged/src/lib/features/diff/DiffCommitSessionLauncher.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { onMount } from 'svelte';
+  import { onMount, tick } from 'svelte';
   import Send from '@lucide/svelte/icons/send';
   import Spinner from '../../shared/Spinner.svelte';
   import { Button } from '$lib/components/ui/button';
@@ -25,7 +25,8 @@
     githubRepo?: string;
     subpath?: string | null;
     isRemote: boolean;
-    onStarted: () => void;
+    onBeforeStart?: () => boolean | Promise<boolean>;
+    onStarted: () => void | Promise<void>;
   }
 
   let {
@@ -38,6 +39,7 @@
     githubRepo,
     subpath,
     isRemote,
+    onBeforeStart = () => true,
     onStarted,
   }: Props = $props();
 
@@ -141,16 +143,21 @@
   }
 
   async function handleSubmit() {
-    let finalPrompt = draftPrompt.trim();
-    if (!finalPrompt || starting) return;
-
-    // Prepend a reference to the review when launched from a review context
-    if (reviewId) {
-      finalPrompt = `Re: #review:${reviewId}\n${finalPrompt}`;
-    }
+    if (starting || !draftPrompt.trim()) return;
 
     starting = true;
     try {
+      if (!(await onBeforeStart())) return;
+      await tick();
+
+      let finalPrompt = draftPrompt.trim();
+      if (!finalPrompt) return;
+
+      // Prepend a reference to the review when launched from a review context
+      if (reviewId) {
+        finalPrompt = `Re: #review:${reviewId}\n${finalPrompt}`;
+      }
+
       await refreshQueueState(true);
 
       const launchContext = {
@@ -172,7 +179,7 @@
         launchContext
       );
 
-      onStarted();
+      await onStarted();
     } catch (e) {
       toast.error('Unable to start commit session', {
         description: e instanceof Error ? e.message : String(e),

apps/staged/src/lib/features/diff/DiffFileTreeSection.svelte

@@ -26,6 +26,7 @@
       isOpen: boolean;
       fileResults: Map<string, FileSearchResult>;
       collapsedSearchResults: Set<string>;
+      currentResultIndex: number;
     };
     toggleSearchResults: (filePath: string) => void;
     areSearchResultsCollapsed: (filePath: string) => boolean;
@@ -42,7 +43,7 @@
       diffCache: Map<string, FileDiff>;
     };
     getCurrentDiff: () => FileDiff | null;
-    selectFile: (path: string) => Promise<void>;
+    selectFile: (path: string) => Promise<boolean | void>;
   }
 
   interface Props {
@@ -56,7 +57,7 @@
     selectedFile: string | null;
     isCollapsed: (path: string) => boolean;
     onToggleDir: (path: string) => void;
-    onSelectFile: (file: FileEntry) => void;
+    onSelectFile: (file: FileEntry) => boolean | void | Promise<boolean | void>;
     onToggleReviewed: (event: MouseEvent | KeyboardEvent, file: FileEntry) => void | Promise<void>;
     onJumpToLine?: (lineIndex: number) => void;
     searchState?: SearchStateHandle;
@@ -129,16 +130,27 @@
   ) {
     if (!searchState || !diffViewerState) return;
 
+    const previousResultIndex = searchState.state.currentResultIndex;
+    const wasCollapsed = searchState.areSearchResultsCollapsed(filePath);
+
     // Update current result index
     searchState.setCurrentResult(globalIndex);
 
     // Auto-expand search results for this file
-    if (searchState.areSearchResultsCollapsed(filePath)) {
+    if (wasCollapsed) {
       searchState.toggleSearchResults(filePath);
     }
 
     // Select the file and scroll to the match
-    await diffViewerState.selectFile(filePath);
+    const selected = (await diffViewerState.selectFile(filePath)) !== false;
+    if (!selected) {
+      searchState.setCurrentResult(previousResultIndex);
+      if (wasCollapsed) {
+        searchState.toggleSearchResults(filePath);
+      }
+      return;
+    }
+
     // Scroll to the specific line
     if (onJumpToLine) {
       onJumpToLine(match.lineIndex);