Merge master into fix/terminal-history-scroll

test/file-preview-media.test.ts

@@ -0,0 +1,178 @@
+/**
+ * @fileoverview File viewer media teardown: closing the preview must stop the video.
+ *
+ * `closeFilePreview()` used to do nothing but drop the overlay's `visible`
+ * class. That hides the overlay (`display: none`) and hides it ONLY: the
+ * `<video>` inside carried on playing, so the audio kept going after the user
+ * pressed X, with no visible player to pause. Detaching the element is not a fix
+ * either — a detached HTMLMediaElement plays until it is garbage collected —
+ * which is why the teardown has to pause() and unload the element explicitly.
+ *
+ * What is pinned here:
+ *   1. close pauses AND unloads every media element (not just the first),
+ *   2. close still works with no media in the body (the common text case),
+ *   3. opening a NEW preview stops what the previous one was playing, since
+ *      overwriting innerHTML only detaches it,
+ *   4. a dirty edit buffer still wins: cancelling the discard prompt must not
+ *      tear the buffer down.
+ *
+ * Loaded via `vm` against a stub app, same harness style as
+ * file-browser-hidden.test.ts (no jsdom).
+ */
+
+import { readFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+import vm from 'node:vm';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const PUBLIC = resolve(import.meta.dirname, '../src/web/public');
+const panelsJs = readFileSync(resolve(PUBLIC, 'panels-ui.js'), 'utf8');
+
+interface FakeMedia {
+  tag: 'video' | 'audio';
+  paused: boolean;
+  src: string | null;
+  loadCalls: number;
+  pause: () => void;
+  removeAttribute: (name: string) => void;
+  load: () => void;
+}
+
+function fakeMedia(tag: 'video' | 'audio'): FakeMedia {
+  const el: FakeMedia = {
+    tag,
+    paused: false,
+    src: 'https://example.test/clip.mp4',
+    loadCalls: 0,
+    pause() {
+      el.paused = true;
+    },
+    removeAttribute(name: string) {
+      if (name === 'src') el.src = null;
+    },
+    load() {
+      el.loadCalls += 1;
+    },
+  };
+  return el;
+}
+
+function loadApp(media: FakeMedia[]) {
+  const CodemanApp = function CodemanApp(this: unknown) {} as unknown as new () => Record<string, unknown>;
+  const context = vm.createContext({
+    CodemanApp,
+    console: { ...console, warn: vi.fn() },
+    localStorage: { getItem: () => null, setItem: () => {}, removeItem: () => {} },
+    escapeHtml: (s: string) => String(s),
+    document: { getElementById: () => null, addEventListener: vi.fn() },
+    window: { addEventListener: vi.fn() },
+    setTimeout,
+    clearTimeout,
+    confirm: () => true,
+    fetch: () => {
+      throw new Error('fetch not stubbed');
+    },
+  });
+  vm.runInContext(panelsJs, context, { filename: 'panels-ui.js' });
+
+  const body = {
+    innerHTML: '<video src="/api/sessions/s1/file-raw?path=clip.mp4" controls></video>',
+    querySelectorAll: (sel: string) => {
+      expect(sel).toBe('video, audio');
+      return media;
+    },
+  };
+  const overlay = {
+    classes: new Set<string>(['visible']),
+    classList: {
+      add: (c: string) => overlay.classes.add(c),
+      remove: (c: string) => overlay.classes.delete(c),
+      contains: (c: string) => overlay.classes.has(c),
+    },
+  };
+  const elements: Record<string, unknown> = { filePreviewBody: body, filePreviewOverlay: overlay };
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const app = new CodemanApp() as Record<string, any>;
+  app.$ = (id: string) => elements[id] ?? null;
+  app.filePreviewContent = 'previous content';
+  app.context = context;
+  return { app, body, overlay, context };
+}
+
+describe('file viewer media teardown', () => {
+  let media: FakeMedia[];
+
+  beforeEach(() => {
+    media = [fakeMedia('video')];
+  });
+
+  it('pauses and unloads the video when the preview is closed', () => {
+    const { app, overlay, body } = loadApp(media);
+
+    app.closeFilePreview();
+
+    expect(overlay.classList.contains('visible')).toBe(false);
+    expect(media[0].paused).toBe(true);
+    // src dropped + load() is what aborts the in-flight fetch; pause() alone
+    // leaves the browser downloading the rest of the file.
+    expect(media[0].src).toBeNull();
+    expect(media[0].loadCalls).toBe(1);
+    expect(body.innerHTML).toBe('');
+  });
+
+  it('stops every media element, not just the first', () => {
+    media = [fakeMedia('video'), fakeMedia('audio')];
+    const { app } = loadApp(media);
+
+    app.closeFilePreview();
+
+    expect(media.every((m) => m.paused && m.src === null)).toBe(true);
+  });
+
+  it('closes cleanly when the preview holds no media (the text case)', () => {
+    const { app, overlay } = loadApp([]);
+
+    expect(() => app.closeFilePreview()).not.toThrow();
+    expect(overlay.classList.contains('visible')).toBe(false);
+    expect(app.filePreviewContent).toBe('');
+  });
+
+  it('survives a media element that throws on teardown', () => {
+    const hostile = fakeMedia('video');
+    hostile.pause = () => {
+      throw new Error('detached');
+    };
+    const { app, overlay } = loadApp([hostile]);
+
+    expect(() => app.closeFilePreview()).not.toThrow();
+    expect(overlay.classList.contains('visible')).toBe(false);
+  });
+
+  it('stops the previous video when another file is previewed', async () => {
+    const { app, context } = loadApp(media);
+    // openFilePreview bails right after the teardown: the fetch stub rejects and
+    // the handler swallows it, which is enough to pin the teardown ordering.
+    context.fetch = async () => ({ ok: false, json: async () => ({ success: false }) });
+    app._resetFilePreviewEdit = () => {};
+    app.$ = ((orig) => (id: string) => (id === 'filePreviewTitle' || id === 'filePreviewFooter' ? {} : orig(id)))(
+      app.$
+    );
+
+    await app.openFilePreview('other.txt', 's1');
+
+    expect(media[0].paused).toBe(true);
+    expect(media[0].src).toBeNull();
+  });
+
+  it('keeps the editor buffer when the discard prompt is declined', () => {
+    const { app, overlay, context } = loadApp(media);
+    context.confirm = () => false;
+    app.filePreviewEdit = { dirty: true };
+
+    app.closeFilePreview();
+
+    expect(overlay.classList.contains('visible')).toBe(true);
+    expect(media[0].paused).toBe(false);
+  });
+});

test/http-range.test.ts

@@ -0,0 +1,101 @@
+/**
+ * @fileoverview Byte-range parsing for the raw file-serving routes.
+ *
+ * The file viewer's video player is only seekable when file-raw answers `Range`
+ * requests with 206 (measured before the fix: `video.seekable` was `[0, 0]` and
+ * `currentTime = x` silently reverted). What that correctness rests on is this
+ * parser, so the cases pinned here are the ones a media element actually emits
+ * plus the malformed input a browser never sends but a client can:
+ *
+ *   - `bytes=0-` — how Chrome opens EVERY media element. Must be 206, not 200.
+ *   - `bytes=-N` — the SUFFIX form (last N bytes), not "from N onwards"; mp4
+ *     players use it to read a trailing moov atom.
+ *   - out of bounds -> 416, malformed -> ignored (200), which are different
+ *     answers for what looks like the same "bad range".
+ */
+
+import { describe, expect, it } from 'vitest';
+import { parseByteRange } from '../src/web/http-range.js';
+
+describe('parseByteRange', () => {
+  it('serves the full file when there is no Range header', () => {
+    expect(parseByteRange(undefined, 1000)).toEqual({ kind: 'full' });
+    expect(parseByteRange('', 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('answers bytes=0- with a partial range (the form Chrome opens media with)', () => {
+    expect(parseByteRange('bytes=0-', 1000)).toEqual({ kind: 'partial', start: 0, end: 999 });
+  });
+
+  it('parses a closed range inclusive of both ends', () => {
+    expect(parseByteRange('bytes=100-199', 1000)).toEqual({ kind: 'partial', start: 100, end: 199 });
+  });
+
+  it('clamps an end past EOF instead of rejecting the range', () => {
+    expect(parseByteRange('bytes=900-5000', 1000)).toEqual({ kind: 'partial', start: 900, end: 999 });
+  });
+
+  it('reads bytes=-N as the LAST N bytes, not as an offset', () => {
+    expect(parseByteRange('bytes=-100', 1000)).toEqual({ kind: 'partial', start: 900, end: 999 });
+  });
+
+  it('clamps a suffix longer than the file to the whole file', () => {
+    expect(parseByteRange('bytes=-5000', 1000)).toEqual({ kind: 'partial', start: 0, end: 999 });
+  });
+
+  it('accepts a single-byte range', () => {
+    expect(parseByteRange('bytes=0-0', 1000)).toEqual({ kind: 'partial', start: 0, end: 0 });
+  });
+
+  it('tolerates whitespace and a capitalised unit', () => {
+    expect(parseByteRange('  BYTES = 10-20 ', 1000)).toEqual({ kind: 'partial', start: 10, end: 20 });
+  });
+
+  it('reports a start at or past EOF as unsatisfiable (416)', () => {
+    expect(parseByteRange('bytes=1000-', 1000)).toEqual({ kind: 'unsatisfiable' });
+    expect(parseByteRange('bytes=1500-1600', 1000)).toEqual({ kind: 'unsatisfiable' });
+  });
+
+  it('reports a zero-length suffix as unsatisfiable', () => {
+    expect(parseByteRange('bytes=-0', 1000)).toEqual({ kind: 'unsatisfiable' });
+  });
+
+  it('reports any range against an empty file as unsatisfiable', () => {
+    expect(parseByteRange('bytes=0-', 0)).toEqual({ kind: 'unsatisfiable' });
+    expect(parseByteRange('bytes=-10', 0)).toEqual({ kind: 'unsatisfiable' });
+  });
+
+  it('ignores an inverted range rather than 416-ing it (invalid spec, not unsatisfiable)', () => {
+    expect(parseByteRange('bytes=500-100', 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('ignores units it does not implement', () => {
+    expect(parseByteRange('items=0-10', 1000)).toEqual({ kind: 'full' });
+    expect(parseByteRange('bytes 0-10', 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('ignores multi-range requests instead of answering only the first range', () => {
+    // A multipart/byteranges body is the only correct answer to these, and no
+    // media element asks for one — serving the whole file is spec-legal.
+    expect(parseByteRange('bytes=0-99,200-299', 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('ignores malformed specs', () => {
+    expect(parseByteRange('bytes=', 1000)).toEqual({ kind: 'full' });
+    expect(parseByteRange('bytes=-', 1000)).toEqual({ kind: 'full' });
+    expect(parseByteRange('bytes=abc-def', 1000)).toEqual({ kind: 'full' });
+    expect(parseByteRange('bytes=1.5-2', 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('ignores a duplicated Range header rather than guessing which one won', () => {
+    expect(parseByteRange(['bytes=0-10', 'bytes=20-30'], 1000)).toEqual({ kind: 'full' });
+  });
+
+  it('bounds an absurdly long offset instead of producing Infinity', () => {
+    // A 100-digit first-byte-pos must not reach createReadStream as Infinity.
+    const huge = '9'.repeat(100);
+    expect(parseByteRange(`bytes=${huge}-`, 1000)).toEqual({ kind: 'unsatisfiable' });
+    const range = parseByteRange(`bytes=0-${huge}`, 1000);
+    expect(range).toEqual({ kind: 'partial', start: 0, end: 999 });
+  });
+});

test/routes/file-routes-range.test.ts

@@ -0,0 +1,204 @@
+/**
+ * @fileoverview Range-request coverage for the raw file-serving routes.
+ *
+ * The file viewer points a `<video>` at `GET /api/sessions/:id/file-raw`. That
+ * route used to read the whole file and answer 200 with no `Accept-Ranges`,
+ * which makes a browser treat the media as unseekable: measured against an 18MB
+ * mp4, `video.seekable` was `[0, 0]` and assigning `currentTime` was reverted on
+ * the next tick, so the scrub bar looked dead.
+ *
+ * These tests pin the wire contract that makes seeking work, since none of it is
+ * visible from a plain 200-vs-404 assertion:
+ *   1. `Accept-Ranges: bytes` on the un-ranged response (what tells the browser
+ *      it MAY seek at all),
+ *   2. 206 + `Content-Range` + the sliced body for a range request,
+ *   3. the slice actually coming from a bounded read, not a full-file read that
+ *      is then truncated,
+ *   4. 416 (with `Content-Range: bytes *​/size`) for a range past EOF, rather
+ *      than a silent full-body 200 the media element cannot interpret.
+ *
+ * Uses app.inject() — no real ports.
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { Readable } from 'node:stream';
+import { createRouteTestHarness, type RouteTestHarness } from './_route-test-utils.js';
+import { registerFileRoutes } from '../../src/web/routes/file-routes.js';
+
+const FILE_BYTES = Buffer.from('0123456789ABCDEFGHIJ'); // 20 bytes, index == value position
+
+vi.mock('node:fs/promises', () => ({
+  default: {
+    readFile: vi.fn(async () => Buffer.from('unused')),
+    stat: vi.fn(async () => ({ size: 20, isFile: () => true, isDirectory: () => false, mtimeMs: 1 })),
+    readdir: vi.fn(async () => []),
+  },
+}));
+
+vi.mock('node:fs', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('node:fs')>();
+  return {
+    ...actual,
+    realpathSync: vi.fn((p: string) => p),
+    // Honour start/end so a test can tell a real bounded read from a full read.
+    createReadStream: vi.fn((_path: string, opts?: { start?: number; end?: number }) => {
+      const start = opts?.start ?? 0;
+      const end = opts?.end ?? FILE_BYTES.length - 1;
+      return Readable.from([FILE_BYTES.subarray(start, end + 1)]);
+    }),
+  };
+});
+
+vi.mock('../../src/file-stream-manager.js', () => ({
+  fileStreamManager: {
+    createStream: vi.fn(async () => ({ success: true, streamId: 'stream-1' })),
+    closeStream: vi.fn(() => true),
+  },
+}));
+
+import fs from 'node:fs/promises';
+import { createReadStream, realpathSync } from 'node:fs';
+
+const mockedStat = vi.mocked(fs.stat);
+const mockedRealpathSync = vi.mocked(realpathSync);
+const mockedCreateReadStream = vi.mocked(createReadStream);
+
+describe('file-raw range requests', () => {
+  let harness: RouteTestHarness;
+  let sid: string;
+
+  beforeEach(async () => {
+    harness = await createRouteTestHarness(registerFileRoutes);
+    vi.clearAllMocks();
+    mockedRealpathSync.mockImplementation((p: string) => p as never);
+    mockedStat.mockResolvedValue({ size: FILE_BYTES.length, isFile: () => true } as never);
+    mockedCreateReadStream.mockImplementation(
+      (_path: unknown, opts?: unknown) =>
+        Readable.from([
+          FILE_BYTES.subarray(
+            (opts as { start?: number })?.start ?? 0,
+            ((opts as { end?: number })?.end ?? FILE_BYTES.length - 1) + 1
+          ),
+        ]) as never
+    );
+    sid = harness.ctx._sessionId as string;
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  const rawUrl = (name = 'clip.mp4') => `/api/sessions/${sid}/file-raw?path=${name}`;
+
+  it('advertises Accept-Ranges on an un-ranged response, so the browser knows it may seek', async () => {
+    const res = await harness.app.inject({ method: 'GET', url: rawUrl() });
+
+    expect(res.statusCode).toBe(200);
+    expect(res.headers['accept-ranges']).toBe('bytes');
+    expect(res.headers['content-type']).toBe('video/mp4');
+    expect(res.headers['content-length']).toBe(String(FILE_BYTES.length));
+    expect(res.rawPayload.equals(FILE_BYTES)).toBe(true);
+  });
+
+  it('answers bytes=0- with 206 (Chrome opens every media element this way)', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=0-' },
+    });
+
+    expect(res.statusCode).toBe(206);
+    expect(res.headers['content-range']).toBe(`bytes 0-19/${FILE_BYTES.length}`);
+    expect(res.headers['content-length']).toBe(String(FILE_BYTES.length));
+    expect(res.rawPayload.equals(FILE_BYTES)).toBe(true);
+  });
+
+  it('serves a mid-file slice from a bounded read', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=5-9' },
+    });
+
+    expect(res.statusCode).toBe(206);
+    expect(res.headers['content-range']).toBe('bytes 5-9/20');
+    expect(res.headers['content-length']).toBe('5');
+    expect(res.rawPayload.toString()).toBe('56789');
+    // The read itself must be bounded: a full read that is sliced afterwards
+    // would still pull an 18MB video into memory on every seek.
+    expect(mockedCreateReadStream).toHaveBeenCalledWith(expect.any(String), { start: 5, end: 9 });
+  });
+
+  it('serves a suffix range as the LAST N bytes', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=-4' },
+    });
+
+    expect(res.statusCode).toBe(206);
+    expect(res.headers['content-range']).toBe('bytes 16-19/20');
+    expect(res.rawPayload.toString()).toBe('GHIJ');
+  });
+
+  it('answers a range past EOF with 416 instead of a full-body 200', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=100-200' },
+    });
+
+    expect(res.statusCode).toBe(416);
+    expect(res.headers['content-range']).toBe('bytes */20');
+    expect(JSON.parse(res.body).success).toBe(false);
+  });
+
+  it('ignores a malformed range and serves the whole file', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=abc-def' },
+    });
+
+    expect(res.statusCode).toBe(200);
+    expect(res.rawPayload.equals(FILE_BYTES)).toBe(true);
+  });
+
+  it('keeps the security headers on a partial response', async () => {
+    // 206 bodies go out through reply.hijack(), which bypasses Fastify's own
+    // header write — the nosniff/type headers have to be carried across by hand.
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl(),
+      headers: { range: 'bytes=0-3' },
+    });
+
+    expect(res.statusCode).toBe(206);
+    expect(res.headers['x-content-type-options']).toBe('nosniff');
+    expect(res.headers['content-type']).toBe('video/mp4');
+  });
+
+  it('supports resuming a download (?download=true) as well as inline playback', async () => {
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: `${rawUrl('clip.mp4')}&download=true`,
+      headers: { range: 'bytes=10-14' },
+    });
+
+    expect(res.statusCode).toBe(206);
+    expect(res.headers['content-disposition']).toContain('attachment; filename="clip.mp4"');
+    expect(res.rawPayload.toString()).toBe('ABCDE');
+  });
+
+  it('still refuses files past the raw size cap before looking at Range', async () => {
+    mockedStat.mockResolvedValue({ size: 100 * 1024 * 1024, isFile: () => true } as never);
+
+    const res = await harness.app.inject({
+      method: 'GET',
+      url: rawUrl('huge.mp4'),
+      headers: { range: 'bytes=0-99' },
+    });
+
+    expect(res.statusCode).toBe(400);
+  });
+});

test/routes/file-routes.test.ts

@@ -6,6 +6,7 @@
  */
 
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { Readable } from 'node:stream';
 import { createRouteTestHarness, type RouteTestHarness } from './_route-test-utils.js';
 import { registerFileRoutes } from '../../src/web/routes/file-routes.js';
 import { ApiErrorCode } from '../../src/types.js';
@@ -19,12 +20,15 @@ vi.mock('node:fs/promises', () => ({
   },
 }));
 
-// Mock realpathSync for symlink resolution
+// Mock realpathSync for symlink resolution, plus createReadStream: file-raw
+// STREAMS its body (range support), so an unmocked read would hit the real
+// filesystem and fail with ENOENT rather than serving the fixture bytes.
 vi.mock('node:fs', async (importOriginal) => {
   const actual = await importOriginal<typeof import('node:fs')>();
   return {
     ...actual,
     realpathSync: vi.fn((p: string) => p),
+    createReadStream: vi.fn(() => Readable.from([Buffer.from('fake file bytes')])),
   };
 });
 
@@ -37,13 +41,14 @@ vi.mock('../../src/file-stream-manager.js', () => ({
 }));
 
 import fs from 'node:fs/promises';
-import { realpathSync } from 'node:fs';
+import { createReadStream, realpathSync } from 'node:fs';
 import { fileStreamManager } from '../../src/file-stream-manager.js';
 
 const mockedReaddir = vi.mocked(fs.readdir);
 const mockedReadFile = vi.mocked(fs.readFile);
 const mockedStat = vi.mocked(fs.stat);
 const mockedRealpathSync = vi.mocked(realpathSync);
+const mockedCreateReadStream = vi.mocked(createReadStream);
 const mockedFileStreamManager = vi.mocked(fileStreamManager);
 
 describe('file-routes', () => {
@@ -55,6 +60,7 @@ describe('file-routes', () => {
 
     // Default: realpathSync returns the path unchanged
     mockedRealpathSync.mockImplementation((p: string) => p as never);
+    mockedCreateReadStream.mockImplementation(() => Readable.from([Buffer.from('fake file bytes')]) as never);
     // Default stat
     mockedStat.mockResolvedValue({ size: 100, isFile: () => true, isDirectory: () => true } as never);
     mockedReadFile.mockImplementation(async (path) =>
@@ -739,7 +745,7 @@ describe('file-routes', () => {
 
     it('serves raw file with correct content type', async () => {
       const content = Buffer.from('fake png data');
-      mockedReadFile.mockResolvedValue(content as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content]) as never);
       mockedStat.mockResolvedValue({ size: content.length } as never);
 
       const res = await harness.app.inject({
@@ -752,7 +758,7 @@ describe('file-routes', () => {
 
     it('serves workspace SVG as an untrusted attachment instead of inline image/svg+xml', async () => {
       const content = Buffer.from('<svg><script>alert("xss")</script></svg>');
-      mockedReadFile.mockResolvedValue(content as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content]) as never);
       mockedStat.mockResolvedValue({ size: content.length } as never);
 
       const res = await harness.app.inject({

test/session-lineage-lines.test.ts

@@ -77,25 +77,47 @@ describe('lineage line geometry', () => {
     expect(first.d).not.toBe(second.d);
   });
 
-  it('switches to a vertical bezier when the strip has wrapped to two rows', () => {
+  it('keeps bending at strip-wide spans instead of flattening into a straight line', () => {
     const helper = loadLineageHelper();
+    // A worker the agent skill starts is appended to the END of the strip, so this
+    // is the span the feature is actually used at. The first shipped clamp (44px)
+    // turned it into a flat thread across the terminal.
+    const wide = helper.computePath({ parent: tab(0), child: tab(1300), strip: { ...STRIP, width: 1500 } })!;
+    const near = helper.computePath({ parent: tab(0), child: tab(140), strip: STRIP })!;
+
+    const wideDip = controlYs(wide.d)[0] - 34;
+    const nearDip = controlYs(near.d)[0] - 34;
+    expect(wideDip).toBeGreaterThan(nearDip * 2);
+    expect(wideDip).toBeGreaterThanOrEqual(80);
+  });
+
+  it('brackets a wrapped pair BELOW the lower row rather than inside the row gap', () => {
+    const helper = loadLineageHelper();
+    // The reported bug: with the desktop strip wrapped, a parent on row 1 (bottom 34)
+    // and its child on row 2 (top 48) are 14px apart, and a parent-bottom → child-TOP
+    // bezier had 14px to bend in, so it drew a flat line hidden in the gap, three
+    // siblings overprinting each other. Both ends now anchor on the tab BOTTOM and the
+    // curve hangs below the LOWER row, the same bracket the flat strip gets.
     const strip: Rect = { left: 0, top: 0, width: 1200, height: 90 };
     const geom = helper.computePath({ parent: tab(0, 4), child: tab(200, 48), strip })!;
 
     expect(geom.sameRow).toBe(false);
-    // Parent bottom (34) → child top (48): the arc travels between rows.
-    expect(geom.d.startsWith('M 60 34')).toBe(true);
-    expect(geom.endY).toBe(48);
+    expect(geom.d.startsWith('M 60 34')).toBe(true); // parent BOTTOM
+    expect(geom.endY).toBe(78); // child BOTTOM, not its top
+    // Every control point clears the lower row by at least the minimum dip.
+    for (const y of controlYs(geom.d)) expect(y).toBeGreaterThanOrEqual(78 + helper.DIP_MIN_PX);
   });
 
-  it('draws upward when the child sits on the row ABOVE its parent', () => {
+  it('draws the same bracket when the child sits on the row ABOVE its parent', () => {
     const helper = loadLineageHelper();
     const strip: Rect = { left: 0, top: 0, width: 1200, height: 90 };
     const geom = helper.computePath({ parent: tab(0, 48), child: tab(200, 4), strip })!;
 
     expect(geom.sameRow).toBe(false);
-    expect(geom.d.startsWith('M 60 48')).toBe(true); // parent TOP edge
-    expect(geom.endY).toBe(34); // child bottom edge
+    expect(geom.d.startsWith('M 60 78')).toBe(true); // parent BOTTOM
+    expect(geom.endY).toBe(34); // child BOTTOM
+    // The parent's row is the lower one here, so that is what the curve clears.
+    for (const y of controlYs(geom.d)) expect(y).toBeGreaterThanOrEqual(78 + helper.DIP_MIN_PX);
   });
 
   it('skips an edge whose tab is scrolled out of the strip', () => {