feat(ui): respect current line when opening in $EDITOR

.changeset/current-line-editor.md

@@ -0,0 +1,5 @@
+---
+"hunkdiff": minor
+---
+
+Open `$EDITOR` at the current line instead of the start of the selected hunk.

src/ui/App.tsx

@@ -417,6 +417,11 @@ export function App({
   const currentLinePaintPending =
     currentLinePaintState.status === "pending" ||
     (currentLinePaintState.status === "ready" && !currentLinePaintMatchesCursor);
+  /** The review stream's current line, or null when line-level navigation is off. */
+  const activeLineCursor = useMemo(
+    () => (cursorLine === "off" ? null : review.lineCursor),
+    [cursorLine, review.lineCursor],
+  );
   const sessionFileViews = useMemo(
     () => (extensions ? resolveExtensionFileViews(extensions.registry).views : []),
     [extensions],
@@ -1222,7 +1227,7 @@ export function App({
 
   /** Step one line: move the current line, or scroll the viewport when there is no marker. */
   const stepDiffLine = (delta: number) => {
-    if (cursorLine === "off" || !review.lineCursor) {
+    if (!activeLineCursor) {
       scrollDiff(delta, "step");
       return;
     }
@@ -1569,6 +1574,7 @@ export function App({
     const message = openSelectedFileInEditor({
       basePath,
       file: selectedFile,
+      lineCursor: activeLineCursor,
       renderer,
       selectedHunk: review.selectedHunk,
     });
@@ -1582,6 +1588,7 @@ export function App({
       triggerRefreshCurrentInput();
     }
   }, [
+    activeLineCursor,
     bootstrap.changeset.sourceLabel,
     bootstrap.input.kind,
     canRefreshCurrentInput,
@@ -1729,8 +1736,7 @@ export function App({
   const startUserNote = useCallback(
     (fileId?: string, hunkIndex?: number, target?: UserNoteLineTarget) => {
       const hoverTarget = fileId === undefined ? activeAddNoteTarget : null;
-      const keyboardTarget =
-        hoverTarget ?? (fileId === undefined && cursorLine !== "off" ? review.lineCursor : null);
+      const keyboardTarget = hoverTarget ?? (fileId === undefined ? activeLineCursor : null);
       const draft = review.startUserNote(
         fileId ?? keyboardTarget?.fileId,
         hunkIndex ?? keyboardTarget?.hunkIndex,
@@ -1742,7 +1748,7 @@ export function App({
         setFocusArea("note");
       }
     },
-    [activeAddNoteTarget, cursorLine, review.lineCursor, review.startUserNote],
+    [activeAddNoteTarget, activeLineCursor, review.startUserNote],
   );
 
   /** Mark the inline draft note textarea as the active keyboard input. */

src/ui/AppHost.edit-in-editor.test.tsx

@@ -0,0 +1,148 @@
+import { afterEach, beforeEach, describe, expect, test } from "bun:test";
+import { testRender } from "@opentui/react/test-utils";
+import { mkdtempSync, realpathSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { act } from "react";
+import type { AppBootstrap } from "../core/types";
+import { createTestVcsAppBootstrap } from "../../test/helpers/app-bootstrap";
+import { createTestDiffFile, lines } from "../../test/helpers/diff-helpers";
+
+const { AppHost } = await import("./AppHost");
+
+const WIDE = { width: 200, height: 24 };
+
+const BEFORE = lines(
+  "const alpha = 1;",
+  "const beta = 2;",
+  "const gamma = 3;",
+  "const delta = 4;",
+  "const epsilon = 5;",
+);
+const AFTER = lines(
+  "const alpha = 1;",
+  "const beta = 22222;",
+  "const gamma = 3;",
+  "const delta = 4;",
+  "const epsilon = 5;",
+);
+
+const originalEditor = process.env.EDITOR;
+const originalSpawnSync = Bun.spawnSync;
+const tempDirs: string[] = [];
+
+let setup: Awaited<ReturnType<typeof testRender>> | undefined;
+
+function createTempWorkspace() {
+  const dir = realpathSync(mkdtempSync(join(tmpdir(), "hunk-apphost-editor-")));
+  tempDirs.push(dir);
+  writeFileSync(join(dir, "sample.ts"), AFTER);
+  return dir;
+}
+
+function mockSpawnSync(implementation: typeof Bun.spawnSync) {
+  const mutableBun = Bun as unknown as { spawnSync: typeof Bun.spawnSync };
+  mutableBun.spawnSync = implementation;
+}
+
+/** Bootstrap one working-tree review whose file really exists under `sourceLabel`. */
+function createEditorBootstrap(sourceLabel: string): AppBootstrap {
+  return createTestVcsAppBootstrap({
+    changesetId: "changeset:edit-in-editor",
+    initialMode: "stack",
+    sourceLabel,
+    files: [
+      createTestDiffFile({
+        after: AFTER,
+        agent: false,
+        before: BEFORE,
+        context: 3,
+        id: "sample",
+        path: "sample.ts",
+      }),
+    ],
+  });
+}
+
+async function flush(target: Awaited<ReturnType<typeof testRender>>) {
+  await act(async () => {
+    await target.renderOnce();
+    await Bun.sleep(0);
+    await target.renderOnce();
+  });
+}
+
+async function pressKeys(target: Awaited<ReturnType<typeof testRender>>, keys: string) {
+  for (const key of keys) {
+    await act(async () => {
+      await target.mockInput.typeText(key);
+    });
+    await flush(target);
+  }
+}
+
+beforeEach(() => {
+  delete process.env.EDITOR;
+});
+
+afterEach(async () => {
+  if (setup) {
+    const current = setup;
+    setup = undefined;
+    await act(async () => {
+      current.renderer.destroy();
+    });
+  }
+
+  if (originalEditor === undefined) {
+    delete process.env.EDITOR;
+  } else {
+    process.env.EDITOR = originalEditor;
+  }
+  mockSpawnSync(originalSpawnSync);
+
+  while (tempDirs.length > 0) {
+    const dir = tempDirs.pop();
+    if (dir) {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  }
+});
+
+describe("AppHost edit-selected-file shortcut", () => {
+  test("pressing e with no $EDITOR surfaces a notice instead of crashing", async () => {
+    setup = await testRender(
+      <AppHost bootstrap={createEditorBootstrap(createTempWorkspace())} />,
+      WIDE,
+    );
+    await flush(setup);
+
+    await pressKeys(setup, "e");
+
+    // openSelectedFileInEditor returns "$EDITOR is not set." which shows as a session notice.
+    expect(setup.captureCharFrame()).toContain("EDITOR is not set");
+  });
+
+  test("pressing e opens the editor at the current line, not the hunk start", async () => {
+    const workspace = createTempWorkspace();
+    process.env.EDITOR = "vim";
+
+    const spawnCalls: string[][] = [];
+    mockSpawnSync(((cmds: string[]) => {
+      spawnCalls.push(cmds);
+      return { exitCode: 1 };
+    }) as unknown as typeof Bun.spawnSync);
+
+    setup = await testRender(<AppHost bootstrap={createEditorBootstrap(workspace)} />, WIDE);
+    await flush(setup);
+
+    // The hunk starts at line 1; step down onto the changed line, then one line past it.
+    await pressKeys(setup, "jje");
+    await pressKeys(setup, "je");
+
+    expect(spawnCalls).toEqual([
+      ["vim", "+2", join(workspace, "sample.ts")],
+      ["vim", "+3", join(workspace, "sample.ts")],
+    ]);
+  });
+});

src/ui/AppHost.sidebar-resize.test.tsx

@@ -196,32 +196,3 @@ describe("AppHost sidebar resize", () => {
     expect(dividerColumn(setup)).toBe(INITIAL_DIVIDER_COLUMN);
   });
 });
-
-describe("AppHost edit-selected-file shortcut", () => {
-  const originalEditor = process.env.EDITOR;
-
-  beforeEach(() => {
-    delete process.env.EDITOR;
-  });
-
-  afterEach(() => {
-    if (originalEditor === undefined) {
-      delete process.env.EDITOR;
-    } else {
-      process.env.EDITOR = originalEditor;
-    }
-  });
-
-  test("pressing e with no $EDITOR surfaces a notice instead of crashing", async () => {
-    setup = await testRender(<AppHost bootstrap={createResizeBootstrap()} />, WIDE);
-    await flush(setup);
-
-    await act(async () => {
-      await setup!.mockInput.typeText("e");
-    });
-    await flush(setup);
-
-    // openSelectedFileInEditor returns "$EDITOR is not set." which shows as a session notice.
-    expect(setup.captureCharFrame()).toContain("EDITOR is not set");
-  });
-});