chore(desktop): remove vestigial listMessages/replaceMessages IPC + DB

After chat_messages became the single source of truth for agent history
(a5b737f), the legacy design_messages path had no live callers. This
cleanup deletes:

- preload: snapshots.listMessages / replaceMessages bindings
- main IPC: snapshots:v1:list-messages / replace-messages handlers and
  channel entries (+ the dead parseDesignIdPayload / parseMessageList
  helpers they fed)
- DB layer: listMessages / replaceMessages exports, rowToMessage mapper
- tests: the DB-level describe block, the IPC describe block, the two
  schema-reject entries, and the leftover listMessages / replaceMessages
  mocks in store.test.ts

What we intentionally leave alone:
- design_messages table itself (DB schema unchanged — old data stays put)
- duplicateDesign's design_messages copy loop (no-op for new designs
  since nobody writes to the table anymore; legacy designs still clone
  their historical rows cleanly)

Both can be removed in a later DB schema migration; out of scope here.

All 362 desktop tests pass; typecheck clean.

Author: hqhq1025

apps/desktop/src/main/snapshots-db.test.ts

@@ -4,7 +4,6 @@
  * No Electron, no filesystem — just better-sqlite3 :memory:.
  */
 
-import { DesignMessageV1 } from '@open-codesign/shared';
 import { describe, expect, it } from 'vitest';
 import {
   appendChatMessage,
@@ -17,10 +16,8 @@ import {
   initInMemoryDb,
   listChatMessages,
   listDesigns,
-  listMessages,
   listSnapshots,
   renameDesign,
-  replaceMessages,
   setDesignThumbnail,
   softDeleteDesign,
   updateChatToolCallStatus,
@@ -371,69 +368,11 @@ describe('softDeleteDesign + listDesigns filter', () => {
   });
 });
 
-describe('design messages: replaceMessages + listMessages', () => {
-  it('persists a message list keyed by design and ordinal', () => {
-    const db = makeDb();
-    const d = createDesign(db);
-    replaceMessages(db, d.id, [
-      { role: 'user', content: 'first' },
-      { role: 'assistant', content: 'reply' },
-      { role: 'user', content: 'second' },
-    ]);
-    const list = listMessages(db, d.id);
-    expect(list).toHaveLength(3);
-    expect(list[0]?.ordinal).toBe(0);
-    expect(list[0]?.role).toBe('user');
-    expect(list[1]?.role).toBe('assistant');
-    expect(list[2]?.content).toBe('second');
-  });
-
-  it('replaces (not appends) when called again', () => {
-    const db = makeDb();
-    const d = createDesign(db);
-    replaceMessages(db, d.id, [{ role: 'user', content: 'a' }]);
-    replaceMessages(db, d.id, [
-      { role: 'user', content: 'b' },
-      { role: 'assistant', content: 'c' },
-    ]);
-    const list = listMessages(db, d.id);
-    expect(list.map((m) => m.content)).toEqual(['b', 'c']);
-  });
-
-  it('persists and loads system role messages (validates against DesignMessageV1)', () => {
-    const db = makeDb();
-    const d = createDesign(db);
-    replaceMessages(db, d.id, [
-      { role: 'system', content: 'you are a designer' },
-      { role: 'user', content: 'make a hero' },
-      { role: 'assistant', content: 'done' },
-    ]);
-    const list = listMessages(db, d.id);
-    expect(list).toHaveLength(3);
-    expect(list[0]?.role).toBe('system');
-    for (const row of list) {
-      expect(() => DesignMessageV1.parse(row)).not.toThrow();
-    }
-  });
-
-  it('cascades: deleting the design row removes its messages', () => {
-    const db = makeDb();
-    const d = createDesign(db);
-    replaceMessages(db, d.id, [{ role: 'user', content: 'doomed' }]);
-    db.prepare('DELETE FROM designs WHERE id = ?').run(d.id);
-    expect(listMessages(db, d.id)).toEqual([]);
-  });
-});
-
 describe('duplicateDesign', () => {
-  it('clones the design row, all messages, and all snapshots with parent rewiring', () => {
+  it('clones the design row and all snapshots with parent rewiring', () => {
     const db = makeDb();
     const source = createDesign(db, 'Source');
     setDesignThumbnail(db, source.id, 'thumbnail preview');
-    replaceMessages(db, source.id, [
-      { role: 'user', content: 'make a hero' },
-      { role: 'assistant', content: 'here you go' },
-    ]);
     const s1 = createSnapshot(db, {
       designId: source.id,
       parentId: null,
@@ -457,9 +396,6 @@ describe('duplicateDesign', () => {
     expect(cloned?.thumbnailText).toBe('thumbnail preview');
     expect(cloned?.id).not.toBe(source.id);
 
-    const clonedMessages = listMessages(db, cloned?.id ?? '');
-    expect(clonedMessages.map((m) => m.content)).toEqual(['make a hero', 'here you go']);
-
     const clonedSnaps = listSnapshots(db, cloned?.id ?? '');
     expect(clonedSnaps).toHaveLength(2);
     const clonedInitial = clonedSnaps.find((s) => s.type === 'initial');

apps/desktop/src/main/snapshots-db.ts

@@ -24,7 +24,6 @@ import type {
   CommentUpdateInput,
   Design,
   DesignFile,
-  DesignMessage,
   DesignSnapshot,
   SnapshotCreateInput,
 } from '@open-codesign/shared';
@@ -364,17 +363,6 @@ function rowToSnapshot(row: SnapshotRow): DesignSnapshot {
   };
 }
 
-function rowToMessage(row: MessageRow): DesignMessage {
-  return {
-    schemaVersion: 1,
-    designId: row.design_id,
-    role: row.role as DesignMessage['role'],
-    content: row.content,
-    ordinal: row.ordinal,
-    createdAt: row.created_at,
-  };
-}
-
 // ---------------------------------------------------------------------------
 // Designs
 // ---------------------------------------------------------------------------
@@ -550,48 +538,6 @@ export function deleteSnapshot(db: Database, id: string): void {
   db.prepare('DELETE FROM design_snapshots WHERE id = ?').run(id);
 }
 
-// ---------------------------------------------------------------------------
-// Messages
-// ---------------------------------------------------------------------------
-
-export function listMessages(db: Database, designId: string): DesignMessage[] {
-  return (
-    db
-      .prepare('SELECT * FROM design_messages WHERE design_id = ? ORDER BY ordinal ASC')
-      .all(designId) as MessageRow[]
-  ).map(rowToMessage);
-}
-
-export interface MessageInput {
-  role: 'user' | 'assistant' | 'system';
-  content: string;
-}
-
-/**
- * Replace the entire message list for a design atomically. We rewrite rather
- * than appending so the renderer's source-of-truth stays trivially in sync —
- * the chat list is small (< 200 entries) so a full rewrite is cheap and avoids
- * ordinal-conflict bugs across edits / cancels / retries.
- */
-export function replaceMessages(
-  db: Database,
-  designId: string,
-  messages: MessageInput[],
-): DesignMessage[] {
-  const now = new Date().toISOString();
-  const tx = db.transaction(() => {
-    db.prepare('DELETE FROM design_messages WHERE design_id = ?').run(designId);
-    const insert = db.prepare(
-      'INSERT INTO design_messages (design_id, ordinal, role, content, created_at) VALUES (?, ?, ?, ?, ?)',
-    );
-    messages.forEach((m, i) => {
-      insert.run(designId, i, m.role, m.content, now);
-    });
-  });
-  tx();
-  return listMessages(db, designId);
-}
-
 // ---------------------------------------------------------------------------
 // Chat messages (Sidebar v2)
 // ---------------------------------------------------------------------------

apps/desktop/src/main/snapshots-ipc.test.ts

@@ -361,8 +361,6 @@ describe('schemaVersion gating', () => {
     ['snapshots:v1:set-thumbnail', { id: 'x', thumbnailText: null }],
     ['snapshots:v1:soft-delete-design', { id: 'x' }],
     ['snapshots:v1:duplicate-design', { id: 'x', name: 'n' }],
-    ['snapshots:v1:list-messages', { designId: 'd' }],
-    ['snapshots:v1:replace-messages', { designId: 'd', messages: [] }],
     [
       'snapshots:v1:create',
       {
@@ -656,37 +654,6 @@ describe('snapshots:v1:duplicate-design', () => {
   });
 });
 
-describe('snapshots:v1:list-messages + replace-messages', () => {
-  it('round-trips a message list', () => {
-    const d = createDesign(db);
-    call(
-      'snapshots:v1:replace-messages',
-      v1({
-        designId: d.id,
-        messages: [
-          { role: 'user', content: 'hello' },
-          { role: 'assistant', content: 'hi' },
-        ],
-      }),
-    );
-    const list = call('snapshots:v1:list-messages', v1({ designId: d.id })) as Array<{
-      role: string;
-      content: string;
-    }>;
-    expect(list.map((m) => m.content)).toEqual(['hello', 'hi']);
-  });
-
-  it('rejects malformed roles', () => {
-    const d = createDesign(db);
-    expect(() =>
-      call(
-        'snapshots:v1:replace-messages',
-        v1({ designId: d.id, messages: [{ role: 'bot', content: 'x' }] }),
-      ),
-    ).toThrow();
-  });
-});
-
 describe('snapshots:v1:get-design', () => {
   it('returns the design row by id', () => {
     const d = createDesign(db, 'Lookup me');

apps/desktop/src/main/snapshots-ipc.ts

@@ -9,29 +9,21 @@
  * initSnapshotsDb().
  */
 
-import type {
-  Design,
-  DesignMessage,
-  DesignSnapshot,
-  SnapshotCreateInput,
-} from '@open-codesign/shared';
+import type { Design, DesignSnapshot, SnapshotCreateInput } from '@open-codesign/shared';
 import { CodesignError } from '@open-codesign/shared';
 import type BetterSqlite3 from 'better-sqlite3';
 import { ipcMain } from './electron-runtime';
 import { getLogger } from './logger';
 import {
-  type MessageInput,
   createDesign,
   createSnapshot,
   deleteSnapshot,
   duplicateDesign,
   getDesign,
   getSnapshot,
   listDesigns,
-  listMessages,
   listSnapshots,
   renameDesign,
-  replaceMessages,
   setDesignThumbnail,
   softDeleteDesign,
 } from './snapshots-db';
@@ -345,27 +337,6 @@ export function registerSnapshotsIpc(db: Database): void {
     logger.info('design.duplicated', { sourceId: r['id'], newId: cloned.id });
     return cloned;
   });
-
-  ipcMain.handle('snapshots:v1:list-messages', (_e: unknown, raw: unknown): DesignMessage[] => {
-    const id = parseDesignIdPayload(raw, 'list-messages');
-    return runDb('list-messages', () => listMessages(db, id));
-  });
-
-  ipcMain.handle('snapshots:v1:replace-messages', (_e: unknown, raw: unknown): DesignMessage[] => {
-    if (typeof raw !== 'object' || raw === null) {
-      throw new CodesignError(
-        'snapshots:v1:replace-messages expects { designId, messages }',
-        'IPC_BAD_INPUT',
-      );
-    }
-    const r = raw as Record<string, unknown>;
-    requireSchemaV1(r, 'snapshots:v1:replace-messages');
-    if (typeof r['designId'] !== 'string' || r['designId'].trim().length === 0) {
-      throw new CodesignError('designId must be a non-empty string', 'IPC_BAD_INPUT');
-    }
-    const messages = parseMessageList(r['messages']);
-    return runDb('replace-messages', () => replaceMessages(db, r['designId'] as string, messages));
-  });
 }
 
 function parseIdPayload(raw: unknown, channel: string): string {
@@ -380,41 +351,6 @@ function parseIdPayload(raw: unknown, channel: string): string {
   return r['id'] as string;
 }
 
-function parseDesignIdPayload(raw: unknown, channel: string): string {
-  if (typeof raw !== 'object' || raw === null) {
-    throw new CodesignError(`snapshots:v1:${channel} expects { designId }`, 'IPC_BAD_INPUT');
-  }
-  const r = raw as Record<string, unknown>;
-  requireSchemaV1(r, `snapshots:v1:${channel}`);
-  if (typeof r['designId'] !== 'string' || r['designId'].trim().length === 0) {
-    throw new CodesignError('designId must be a non-empty string', 'IPC_BAD_INPUT');
-  }
-  return r['designId'] as string;
-}
-
-function parseMessageList(raw: unknown): MessageInput[] {
-  if (!Array.isArray(raw)) {
-    throw new CodesignError('messages must be an array', 'IPC_BAD_INPUT');
-  }
-  const validRoles = ['user', 'assistant', 'system'] as const;
-  return raw.map((entry, index) => {
-    if (typeof entry !== 'object' || entry === null) {
-      throw new CodesignError(`messages[${index}] must be an object`, 'IPC_BAD_INPUT');
-    }
-    const e = entry as Record<string, unknown>;
-    if (!validRoles.includes(e['role'] as (typeof validRoles)[number])) {
-      throw new CodesignError(
-        `messages[${index}].role must be one of: ${validRoles.join(', ')}`,
-        'IPC_BAD_INPUT',
-      );
-    }
-    if (typeof e['content'] !== 'string') {
-      throw new CodesignError(`messages[${index}].content must be a string`, 'IPC_BAD_INPUT');
-    }
-    return { role: e['role'] as MessageInput['role'], content: e['content'] as string };
-  });
-}
-
 /**
  * Stub channels installed when snapshots DB init fails at boot. Without these,
  * any renderer call to window.codesign.snapshots.* would surface as Electron's
@@ -432,8 +368,6 @@ export const SNAPSHOTS_CHANNELS_V1 = [
   'snapshots:v1:set-thumbnail',
   'snapshots:v1:soft-delete-design',
   'snapshots:v1:duplicate-design',
-  'snapshots:v1:list-messages',
-  'snapshots:v1:replace-messages',
   'snapshots:v1:list',
   'snapshots:v1:get',
   'snapshots:v1:create',

apps/desktop/src/preload/index.ts

@@ -7,7 +7,6 @@ import type {
   CommentRow,
   CommentStatus,
   Design,
-  DesignMessage,
   DesignSnapshot,
   GeneratePayloadV1,
   LocalInputFile,
@@ -386,17 +385,6 @@ const api = {
         id,
         name,
       }) as Promise<Design>,
-    listMessages: (designId: string) =>
-      ipcRenderer.invoke('snapshots:v1:list-messages', {
-        schemaVersion: 1,
-        designId,
-      }) as Promise<DesignMessage[]>,
-    replaceMessages: (designId: string, messages: Array<{ role: string; content: string }>) =>
-      ipcRenderer.invoke('snapshots:v1:replace-messages', {
-        schemaVersion: 1,
-        designId,
-        messages,
-      }) as Promise<DesignMessage[]>,
     list: (designId: string) =>
       ipcRenderer.invoke('snapshots:v1:list', { schemaVersion: 1, designId }) as Promise<
         DesignSnapshot[]