fix(windows): 单文件工作区 Diff 可展开省略的代码行 (#557)

.agents/notes/implemented/architecture/2026-09-15-macos-monaco-feasibility-probe.md

@@ -423,6 +423,23 @@ working-tree review 的显式身份，不回退到可能已经切换的工作区
 错误通过现有本地化提示呈现。纯逻辑回归覆盖稀疏分块、两种操作及这些生命周期边界，
 并纳入 Windows Git 随机顺序 CI；真实 WebView2 的按钮与 Git 状态联动仍需宿主验收。
 
+Windows 单文件工作区 Diff 还要能展开省略的未改动代码（#557）。稀疏补丁里根本
+没有这些行，所以“展开”无从谈起；之前强行关闭折叠，结果连展开按钮都不显示。
+现在单文件打开和刷新时请求整份文件作为上下文（`contextLines` 取 Git 接受的
+最大值 2147483647），结果标记为完整上下文（`is_full_context`），只有这种补丁
+才开启 Monaco 的未改动区域折叠。多文件、历史和提交比较仍用稀疏补丁且不折叠，
+因为它们缺少的行同样无法展示。
+
+整份文件只有一个 `@@`，直接拿来暂存会把整个文件一次写进索引。因此 Windows
+适配器按 Git 默认的 3 行上下文重新切出分块，自己生成 `@@` 范围；单测用同一次
+修改的真实 `git diff` 输出逐块比对。完整上下文没有 `@@` 行，渲染器改用行上的
+`actionAnchor` 标记放置按钮，并按每一侧实际显示的行数计算位置，左右两侧保持对齐。
+
+Monaco 会把旧的折叠状态带到新内容上：挂载时的空模型没有未改动区域，第一份
+真实文本的所有区域都会被当作“已展开”。渲染器在文本被替换时重新挂接模型，
+让折叠状态从头计算；文本相同的刷新不重挂，读者已展开的区域保留。
+真实 WebKit 回归覆盖首次折叠、单个按钮和搜索揭示，去掉重挂会失败。
+
 预览借用主编辑器时还保存查找栏的查询、选项和显隐状态。关闭预览必须恢复
 主编辑器原先的查找状态，不能把替换预览的查询栏留在原文件中。
 

docs/development/platform-parity-matrix.csv

@@ -32,7 +32,7 @@ search-replace,搜索,搜索与导航,项目替换与取消,已实现,待验证,
 git-status-commit,版本控制,Git,状态、暂存与提交,已实现,待验证,已实现,待验证,Git,修改、暂存、取消暂存并提交文件，确认状态、提交消息和错误回显。 Windows 另验证原生 UNC/verbatim 输入、中文/空格/长路径仓库往返及 linked worktree；末尾点/空格必须明确拒绝，外部提交/切换须触发元数据刷新。,,macos/Sources/Lithe/Views/Git; macos/Sources/Lithe/Services,windows/tauri/src/features/git; shared/contracts/application-boundary.md; windows/tauri/src/features/git/api/git-repository-path.ts; rust/lithe-core/tests/git_path_roundtrip.rs; shared/fixtures/git/windows-paths.json
 git-multi-repository-change-groups,版本控制,Git,多仓库变更折叠分组,已实现,待验证,已实现,待验证,Git,在同一工作区打开多个 Git 仓库，确认变更按仓库折叠分组；只剩一个仓库有变更时仍显示仓库名。仓库级和文件级勾选与 Git 暂存区同步；子模块只有未提交文件时显示提示，不能勾选未变化的引用。,两端直接消费共享 Rust Core 的计划、依赖排序、执行结果与重试。平台负责真实暂存勾选、确认与结果界面、认证取消和项目生命周期。原生界面实测待平台验收。,macos/Sources/Lithe/Views/Git/ChangesSidebarView.swift; macos/Sources/Lithe/Views/Git/GitChangeSectionsCache.swift; macos/Sources/LitheGitModule/Models/GitModels.swift; rust/lithe-core/src/git/mod.rs,windows/tauri/src/features/git/components/status/git-status-panel.tsx; windows/tauri/src/features/git/components/git-commit-panel.tsx; windows/tauri/src/features/git/components/git-workspace-commit-review.tsx; windows/tauri/src/features/git/services/git-workspace-commit-workflow.ts; windows/tauri/src/features/git/services/git-workspace-commit-workflow.test.ts; windows/tauri/src/features/git/components/status/git-workspace-status-panel.test.tsx; windows/tauri/src-tauri/src/platform.rs; shared/fixtures/git/workspace-commit-workflow-v1.json
 git-branches-remotes,版本控制,Git,分支、标签与远程,已实现,待验证,已实现,待验证,Git,创建、切换、合并分支并查看标签和远程，确认冲突与认证失败可恢复。,,macos/Sources/Lithe/Views/Git,windows/tauri/src/features/git
-git-diff-review,版本控制,Git,Diff 与变更审查,已实现,待验证,已实现,待验证,Git,验证新增、删除、重命名、二进制和多文件 Diff 的展示与定位；从源代码管理打开已修改和未跟踪文件的工作区 Diff 后保持静止，确认 Diff 不会自动关闭，且只在文件不再出现在 Git 状态中时关闭。,,macos/Sources/Lithe/Views/Git; macos/Sources/Lithe/Views/Diff,windows/tauri/src/features/git; windows/tauri/src/features/viewer
+git-diff-review,版本控制,Git,Diff 与变更审查,已实现,待验证,已实现,待验证,Git,验证新增、删除、重命名、二进制和多文件 Diff 的展示与定位；从源代码管理打开已修改和未跟踪文件的工作区 Diff 后保持静止，确认 Diff 不会自动关闭，且只在文件不再出现在 Git 状态中时关闭；在 Windows 单文件工作区 Diff 中点击折叠条展开省略的未改动代码，确认 Diff 保持打开且每个修改块仍可单独暂存。,,macos/Sources/Lithe/Views/Git; macos/Sources/Lithe/Views/Diff,windows/tauri/src/features/git; windows/tauri/src/features/viewer
 git-history,版本控制,Git,提交历史与图谱,已实现,待验证,已实现,待验证,Git,分页浏览提交历史、分支图谱和提交详情，确认日期、作者和文件列表一致；分支最新提交的图谱连线从提交圆点开始，不超出到圆点上方；在双端使用同一包含本地分支、远端引用、标签和合并提交的仓库，核对永久图布局、图头引用排序、合并边投影及跨越 30 行的紧凑长边；在本地分支新增提交后确认分支颜色保持稳定，且不会因共用屏幕泳道直接沿用父分支颜色。双端保留各自调色板，不要求 RGB 值一致。,,macos/Sources/Lithe/Views/Git; macos/Sources/LitheGitModule/Services/GitGraphLayoutService.swift; macos/Sources/LitheGitModule/Services/GitGraphHeadOrdering.swift; macos/Sources/Lithe/Views/Git/GitGraphColor.swift,windows/tauri/src/features/git; windows/tauri/src/features/git/utils/git-graph-layout.ts; windows/tauri/src/features/git/utils/git-graph-colors.ts; windows/tauri/src/features/git/utils/git-graph-layout.test.ts
 git-rebase-stash,版本控制,Git,Rebase 与 Stash,已实现,待验证,已实现,待验证,Git,执行交互式 Rebase 和 Stash 保存/恢复，确认中断、冲突和继续操作。,,macos/Sources/Lithe/Views/Git,windows/tauri/src/features/git
 git-worktrees,版本控制,Git,Worktree 管理,已实现,待验证,已实现,待验证,Git,列出、创建、切换和删除 Worktree，确认路径、分支和安全检查。,,macos/Sources/Lithe/Views/Git,windows/tauri/src/features/git

docs/development/platform-parity-matrix.md

@@ -115,7 +115,7 @@
 | Git | **状态、暂存与提交**<br><sub>git-status-commit</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`、`macos/Sources/Lithe/Services`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`、`shared/contracts/application-boundary.md`、`windows/tauri/src/features/git/api/git-repository-path.ts`、`rust/lithe-core/tests/git_path_roundtrip.rs`、`shared/fixtures/git/windows-paths.json`</sub> | Git | 修改、暂存、取消暂存并提交文件，确认状态、提交消息和错误回显。 Windows 另验证原生 UNC/verbatim 输入、中文/空格/长路径仓库往返及 linked worktree；末尾点/空格必须明确拒绝，外部提交/切换须触发元数据刷新。 |  |
 | Git | **多仓库变更折叠分组**<br><sub>git-multi-repository-change-groups</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git/ChangesSidebarView.swift`、`macos/Sources/Lithe/Views/Git/GitChangeSectionsCache.swift`、`macos/Sources/LitheGitModule/Models/GitModels.swift`、`rust/lithe-core/src/git/mod.rs`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git/components/status/git-status-panel.tsx`、`windows/tauri/src/features/git/components/git-commit-panel.tsx`、`windows/tauri/src/features/git/components/git-workspace-commit-review.tsx`、`windows/tauri/src/features/git/services/git-workspace-commit-workflow.ts`、`windows/tauri/src/features/git/services/git-workspace-commit-workflow.test.ts`、`windows/tauri/src/features/git/components/status/git-workspace-status-panel.test.tsx`、`windows/tauri/src-tauri/src/platform.rs`、`shared/fixtures/git/workspace-commit-workflow-v1.json`</sub> | Git | 在同一工作区打开多个 Git 仓库，确认变更按仓库折叠分组；只剩一个仓库有变更时仍显示仓库名。仓库级和文件级勾选与 Git 暂存区同步；子模块只有未提交文件时显示提示，不能勾选未变化的引用。 | 两端直接消费共享 Rust Core 的计划、依赖排序、执行结果与重试。平台负责真实暂存勾选、确认与结果界面、认证取消和项目生命周期。原生界面实测待平台验收。 |
 | Git | **分支、标签与远程**<br><sub>git-branches-remotes</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`</sub> | Git | 创建、切换、合并分支并查看标签和远程，确认冲突与认证失败可恢复。 |  |
-| Git | **Diff 与变更审查**<br><sub>git-diff-review</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`、`macos/Sources/Lithe/Views/Diff`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`、`windows/tauri/src/features/viewer`</sub> | Git | 验证新增、删除、重命名、二进制和多文件 Diff 的展示与定位；从源代码管理打开已修改和未跟踪文件的工作区 Diff 后保持静止，确认 Diff 不会自动关闭，且只在文件不再出现在 Git 状态中时关闭。 |  |
+| Git | **Diff 与变更审查**<br><sub>git-diff-review</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`、`macos/Sources/Lithe/Views/Diff`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`、`windows/tauri/src/features/viewer`</sub> | Git | 验证新增、删除、重命名、二进制和多文件 Diff 的展示与定位；从源代码管理打开已修改和未跟踪文件的工作区 Diff 后保持静止，确认 Diff 不会自动关闭，且只在文件不再出现在 Git 状态中时关闭；在 Windows 单文件工作区 Diff 中点击折叠条展开省略的未改动代码，确认 Diff 保持打开且每个修改块仍可单独暂存。 |  |
 | Git | **提交历史与图谱**<br><sub>git-history</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`、`macos/Sources/LitheGitModule/Services/GitGraphLayoutService.swift`、`macos/Sources/LitheGitModule/Services/GitGraphHeadOrdering.swift`、`macos/Sources/Lithe/Views/Git/GitGraphColor.swift`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`、`windows/tauri/src/features/git/utils/git-graph-layout.ts`、`windows/tauri/src/features/git/utils/git-graph-colors.ts`、`windows/tauri/src/features/git/utils/git-graph-layout.test.ts`</sub> | Git | 分页浏览提交历史、分支图谱和提交详情，确认日期、作者和文件列表一致；分支最新提交的图谱连线从提交圆点开始，不超出到圆点上方；在双端使用同一包含本地分支、远端引用、标签和合并提交的仓库，核对永久图布局、图头引用排序、合并边投影及跨越 30 行的紧凑长边；在本地分支新增提交后确认分支颜色保持稳定，且不会因共用屏幕泳道直接沿用父分支颜色。双端保留各自调色板，不要求 RGB 值一致。 |  |
 | Git | **Rebase 与 Stash**<br><sub>git-rebase-stash</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`</sub> | Git | 执行交互式 Rebase 和 Stash 保存/恢复，确认中断、冲突和继续操作。 |  |
 | Git | **Worktree 管理**<br><sub>git-worktrees</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`macos/Sources/Lithe/Views/Git`</sub> | ✅ 已实现<br><sub>🔍 待验证</sub><br><sub>`windows/tauri/src/features/git`</sub> | Git | 列出、创建、切换和删除 Worktree，确认路径、分支和安全检查。 |  |

frontend/editor/src/diff-review.ts

@@ -10,6 +10,9 @@ export interface ReviewRow {
   right: string | null;
   kind: "context" | "changed" | "addition" | "removal" | "information";
   hunkID?: string | null;
+  /** Renders the hunk's action band above this row. Full-file reviews have no
+   * `@@` information rows, so the host marks each hunk's first change instead. */
+  actionAnchor?: boolean;
 }
 export interface ReviewAction { id: string; title: string }
 export interface DiffReviewInput {
@@ -136,8 +139,14 @@ export function mountDiffReview(container: HTMLElement,
       leftRows = old.rows; rightRows = next.rows;
       if (original.getLanguageId() !== input.language) monaco.editor.setModelLanguage(original, input.language);
       if (modified.getLanguageId() !== input.language) monaco.editor.setModelLanguage(modified, input.language);
+      const replaced = original.getValue() !== old.text || modified.getValue() !== next.text;
       if (original.getValue() !== old.text) original.setValue(old.text);
       if (modified.getValue() !== next.text) modified.setValue(next.text);
+      // Monaco carries fold state across content changes: regions that did not
+      // exist before, such as every region of the first real text after the
+      // empty mount, open fully revealed. Re-attaching the models starts a
+      // fresh diff view model whose unchanged regions fold, like a new review.
+      if (replaced) { editor.setModel(null); editor.setModel({ original, modified }); }
       left.updateOptions({ lineNumbers: line => String(leftRows[line - 1]?.oldLine ?? "") });
       right.updateOptions({ lineNumbers: line => String(rightRows[line - 1]?.newLine ?? "") });
       editor.updateOptions({ renderSideBySide: input.sideBySide ?? true,
@@ -146,11 +155,19 @@ export function mountDiffReview(container: HTMLElement,
       container.classList.toggle("no-word-highlights", input.highlightWords === false);
       const actions = input.actions ?? [];
       if (actions.length) {
-        for (const [view, rows] of [[left, leftRows], [right, rightRows]] as const) {
+        for (const [view, side] of [[left, "left"], [right, "right"]] as const) {
           const ids: string[] = [];
           view.changeViewZones(accessor => {
-            rows.forEach((row, index) => {
-              if (row.kind !== "information" || !row.hunkID) return;
+            let projected = 0;
+            for (const row of input.rows) {
+              const visible = row[side] !== null;
+              // An `@@` row owns the band below it. An anchor row may be absent
+              // from this side (an addition on the left), so its band goes after
+              // the rows this side has already shown, keeping both sides level.
+              const afterLineNumber = row.hunkID && row.actionAnchor ? projected
+                : row.hunkID && row.kind === "information" && visible ? projected + 1 : null;
+              if (visible) projected++;
+              if (afterLineNumber === null) continue;
               const node = document.createElement("div");
               node.className = "lithe-review-actions";
               if (view === right) for (const action of actions) {
@@ -159,8 +176,8 @@ export function mountDiffReview(container: HTMLElement,
                 button.onclick = () => { if (!disposed && request === version) onAction(row.hunkID!, action.id); };
                 node.append(button);
               }
-              ids.push(accessor.addZone({ afterLineNumber: index + 1, heightInPx: 26, domNode: node }));
-            });
+              ids.push(accessor.addZone({ afterLineNumber, heightInPx: 26, domNode: node }));
+            }
           });
           zones.push({ view, ids });
         }

macos/Experiments/Monaco/workbench.integration.ts

@@ -117,6 +117,45 @@ async function verify() {
       subscription?.dispose(); review.dispose(); container.remove();
     }
   });
+  // #557: the first text after the empty mount used to open with every
+  // unchanged region revealed, so a full-file review showed nothing to expand.
+  await check("first full-file diff folds unchanged regions and anchors hunk actions", async () => {
+    const container = document.createElement("div");
+    container.style.cssText = "position:absolute;inset:0;height:400px;width:1000px";
+    document.body.append(container);
+    const review = mountDiffReview(container);
+    const rows: ReviewRow[] = Array.from({ length: 120 }, (_, index) => ({
+      id: `full-${index}`, oldLine: index + 1, newLine: index + 1,
+      left: `value ${index}`, right: index === 4 ? "changed" : `value ${index}`,
+      kind: index === 4 ? "changed" : "context", hunkID: index < 8 ? "hunk-4" : null,
+      ...(index === 4 ? { actionAnchor: true } : {}),
+    }));
+    let subscription: { dispose(): void } | undefined;
+    let deadline: ReturnType<typeof setTimeout> | undefined;
+    try {
+      const computed = new Promise<void>((resolve, reject) => {
+        deadline = setTimeout(() => reject(new Error("Full-file diff computation exceeded 5 seconds")), 5000);
+        subscription = review.editor.onDidUpdateDiff(() => {
+          if (review.editor.getLineChanges()?.length) resolve();
+        });
+      });
+      await Promise.all([review.update({ rows, language: "plaintext", collapse: true,
+        actions: [{ id: "stage", title: "Stage" }] }), computed]);
+      const next = review.editor.getModifiedEditor();
+      // Content height, unlike the viewport, shrinks only when lines are folded.
+      const lineHeight = next.getOption(monacoEditor.EditorOption.lineHeight);
+      assert(next.getContentHeight() < lineHeight * 40,
+        "unchanged region opened revealed instead of folded");
+      assert(container.querySelectorAll(".lithe-review-actions button").length === 1,
+        "full-file hunk did not render exactly one action band");
+      review.select({ revealID: "full-60", searchIDs: ["full-60"] });
+      assert(next.getVisibleRanges().some(range => range.startLineNumber <= 61 && range.endLineNumber >= 61),
+        "folded source row could not be revealed");
+    } finally {
+      if (deadline !== undefined) clearTimeout(deadline);
+      subscription?.dispose(); review.dispose(); container.remove();
+    }
+  });
   await check("inline diff navigation scrolls to a removed source row", async () => {
     const container = document.createElement("div");
     container.style.cssText = "position:absolute;inset:0;height:400px;width:1000px";