ci: check that files copied across the three atlases stay identical

.github/workflows/shared.yml

@@ -0,0 +1,26 @@
+name: shared files
+
+# The three atlases copy a few terminal primitives byte for byte: catch a copy left behind.
+on:
+  pull_request:
+    paths: ['src/browser.ts', 'src/ui/mouse.ts', 'src/ui/palette.ts', 'src/ui/render.ts', 'src/ui/width.ts', 'src/ui/ListSelect.tsx', 'scripts/check-shared.ts', '.github/workflows/shared.yml']
+  # A sibling can change too: check once a week against their main branches.
+  schedule:
+    - cron: '23 5 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  drift:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+      - run: npm ci
+      - run: npm run check:shared

package.json

@@ -19,6 +19,7 @@
     "dev": "tsx src/launch.ts",
     "crawl": "tsx scripts/crawl.ts",
     "demo": "tsx scripts/build-demo.ts",
+    "check:shared": "tsx scripts/check-shared.ts",
     "sync-agents": "tsx scripts/sync-agents.ts",
     "reclassify": "tsx scripts/reclassify.ts",
     "typecheck": "tsc --noEmit",

scripts/check-shared.ts

@@ -0,0 +1,56 @@
+/**
+ * skills-atlas, mcp-atlas and plugins-atlas copy a few terminal primitives byte for byte
+ * instead of sharing a package (the rest of their code has diverged too far for one).
+ * This checks that the copies still match, so that a fix made in one reaches the others.
+ *
+ *   npm run check:shared              compare with each sibling's main branch on GitHub
+ *   npm run check:shared -- --local   compare with sibling checkouts next to this one (../mcp-atlas…)
+ *
+ * Exits with 1 and names the files that differ.
+ */
+import { readFile } from 'node:fs/promises';
+import { join } from 'node:path';
+
+/** File under src/ → the sibling repositories that must hold the same bytes. */
+export const SHARED: Record<string, string[]> = {
+  'browser.ts': ['mcp-atlas', 'plugins-atlas'],
+  'ui/mouse.ts': ['mcp-atlas', 'plugins-atlas'],
+  'ui/palette.ts': ['mcp-atlas', 'plugins-atlas'],
+  'ui/render.ts': ['mcp-atlas', 'plugins-atlas'],
+  'ui/width.ts': ['mcp-atlas', 'plugins-atlas'],
+  // plugins-atlas reads its strings from its own messages module, not i18n.
+  'ui/ListSelect.tsx': ['mcp-atlas'],
+};
+
+const normalize = (text: string) => text.replace(/\r\n?/g, '\n');
+
+export async function drift(read: (repo: string, file: string) => Promise<string>, own = (file: string) => readFile(join('src', file), 'utf8')) {
+  const out: { file: string; repo: string; error?: string }[] = [];
+  for (const [file, repos] of Object.entries(SHARED)) {
+    const mine = normalize(await own(file));
+    for (const repo of repos) {
+      try {
+        if (normalize(await read(repo, file)) !== mine) out.push({ file, repo });
+      } catch (err) {
+        out.push({ file, repo, error: err instanceof Error ? err.message : String(err) });
+      }
+    }
+  }
+  return out;
+}
+
+const fromGitHub = async (repo: string, file: string) => {
+  const res = await fetch(`https://raw.githubusercontent.com/devohmycode/${repo}/main/src/${file}`, { signal: AbortSignal.timeout(20_000) });
+  if (!res.ok) throw new Error(`HTTP ${res.status}`);
+  return res.text();
+};
+const fromSibling = (repo: string, file: string) => readFile(join('..', repo, 'src', file), 'utf8');
+
+if (process.argv[1]?.endsWith('check-shared.ts')) {
+  const local = process.argv.includes('--local');
+  const found = await drift(local ? fromSibling : fromGitHub);
+  for (const d of found) console.error(`${d.error ? 'unreadable' : 'differs   '}  src/${d.file}  ${d.repo}${d.error ? `: ${d.error}` : ''}`);
+  const checked = Object.values(SHARED).reduce((n, r) => n + r.length, 0);
+  console.log(found.length ? `${found.length} of ${checked} shared copies out of step` : `${checked} shared copies match (${local ? 'local checkouts' : 'GitHub main'})`);
+  process.exitCode = found.length ? 1 : 0;
+}

test/shared.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from 'vitest';
+import { drift, SHARED } from '../scripts/check-shared.js';
+
+describe('shared files check', () => {
+  it('reports copies that differ or cannot be read, ignoring line endings', async () => {
+    const own = async (file: string) => `${file}\n`;
+    const found = await drift(async (repo, file) => {
+      if (repo === 'plugins-atlas' && file === 'ui/mouse.ts') return 'changed\n';
+      if (repo === 'mcp-atlas' && file === 'ui/width.ts') throw new Error('HTTP 404');
+      return `${file}\r\n`;
+    }, own);
+    expect(found).toEqual([{ file: 'ui/mouse.ts', repo: 'plugins-atlas' }, { file: 'ui/width.ts', repo: 'mcp-atlas', error: 'HTTP 404' }]);
+    expect(Object.keys(SHARED)).toContain('browser.ts');
+  });
+});