ci: add diff coverage workflow enforcing 80% on changed code only

Uses diff-cover to check that newly added or modified lines in PRs
have at least 80% test coverage, without requiring the entire
codebase to meet the threshold.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/coverage.yml

@@ -0,0 +1,65 @@
+name: PR Diff Coverage
+
+on:
+  pull_request:
+    branches: [main]
+
+concurrency:
+  group: coverage-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  diff-coverage:
+    name: Diff Coverage (80% on changed code)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: pnpm/action-setup@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: pnpm
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+
+      - name: Install diff-cover
+        run: pip install diff-cover
+
+      - name: Install tmux
+        run: sudo apt-get update && sudo apt-get install -y tmux
+
+      - name: Start tmux server
+        run: tmux start-server
+
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm -r --filter '!@composio/ao-web' build
+
+      - name: Core tests with coverage
+        run: pnpm --filter @composio/ao-core exec vitest run --coverage
+
+      - name: CLI tests with coverage
+        run: pnpm --filter @composio/ao-cli exec vitest run --coverage
+
+      - name: Web tests with coverage
+        run: pnpm --filter @composio/ao-web exec vitest run --coverage
+
+      - name: Prepare lcov reports
+        run: |
+          mkdir -p combined-coverage
+          # Prefix source paths so they match git diff (repo-root-relative)
+          sed 's|^SF:|SF:packages/core/|' packages/core/coverage/lcov.info > combined-coverage/core.info
+          sed 's|^SF:|SF:packages/cli/|' packages/cli/coverage/lcov.info > combined-coverage/cli.info
+          sed 's|^SF:|SF:packages/web/|' packages/web/coverage/lcov.info > combined-coverage/web.info
+          cat combined-coverage/core.info combined-coverage/cli.info combined-coverage/web.info > combined-coverage/lcov.info
+
+      - name: Check diff coverage (80% on changed lines)
+        run: |
+          diff-cover combined-coverage/lcov.info \
+            --compare-branch=origin/${{ github.base_ref }} \
+            --fail-under=80 \
+            --diff-range-notation='...'

packages/cli/vitest.config.ts

@@ -11,5 +11,9 @@ export default defineConfig({
         maxThreads: 8,
       },
     },
+    coverage: {
+      provider: "v8",
+      reporter: ["lcov"],
+    },
   },
 });

packages/core/vitest.config.ts

@@ -16,5 +16,11 @@ export default defineConfig({
       ),
       "@composio/ao-plugin-scm-github": resolve(__dirname, "../plugins/scm-github/src/index.ts"),
     },
+    coverage: {
+      provider: "v8",
+      reporter: ["lcov"],
+      include: ["src/**/*.ts"],
+      exclude: ["src/__tests__/**", "src/index.ts", "src/recovery/index.ts"],
+    },
   },
 });

packages/web/package.json

@@ -62,6 +62,7 @@
     "tailwindcss": "^4.0.0",
     "tsx": "^4.19.0",
     "typescript": "^5.7.0",
+    "@vitest/coverage-v8": "^2.1.0",
     "vitest": "^2.1.0"
   }
 }

packages/web/vitest.config.ts

@@ -9,6 +9,11 @@ export default defineConfig({
     environment: "jsdom",
     setupFiles: ["./src/__tests__/setup.ts"],
     include: ["src/**/*.test.{ts,tsx}", "server/**/*.test.ts"],
+    coverage: {
+      provider: "v8",
+      reporter: ["lcov"],
+      include: ["src/**/*.{ts,tsx}", "server/**/*.ts"],
+    },
   },
   resolve: {
     alias: {

pnpm-lock.yaml

@@ -649,6 +649,9 @@ importers:
       '@vitejs/plugin-react':
         specifier: ^4.3.0
         version: 4.7.0(vite@5.4.21(@types/node@25.2.3)(lightningcss@1.30.2))
+      '@vitest/coverage-v8':
+        specifier: ^2.1.0
+        version: 2.1.9(vitest@2.1.9(@types/node@25.2.3)(jsdom@25.0.1)(lightningcss@1.30.2))
       concurrently:
         specifier: ^9.2.1
         version: 9.2.1
@@ -803,6 +806,9 @@ packages:
     resolution: {integrity: sha512-LwdZHpScM4Qz8Xw2iKSzS+cfglZzJGvofQICy7W7v4caru4EaAmyUuO6BGrbyQ2mYV11W0U8j5mBhd14dd3B0A==}
     engines: {node: '>=6.9.0'}
 
+  '@bcoe/v8-coverage@0.2.3':
+    resolution: {integrity: sha512-0hYQ8SB4Db5zvZB4axdMHGwEaQjkZzFjQiN9LVYvIFB2nSUHW9tYpxWriPrWDASIxiaXax83REcLxuSdnGPZtw==}
+
   '@bcoe/v8-coverage@1.0.2':
     resolution: {integrity: sha512-6zABk/ECA/QYSCQ1NGiVwwbQerUCZ+TQbp64Q3AgmfNvurHH0j8TtXa1qbShXA6qqkpAj4V5W8pP6mLe1mcMqA==}
     engines: {node: '>=18'}
@@ -2001,6 +2007,15 @@ packages:
     peerDependencies:
       vite: ^4.2.0 || ^5.0.0 || ^6.0.0 || ^7.0.0
 
+  '@vitest/coverage-v8@2.1.9':
+    resolution: {integrity: sha512-Z2cOr0ksM00MpEfyVE8KXIYPEcBFxdbLSs56L8PO0QQMxt/6bDj45uQfxoc96v05KW3clk7vvgP0qfDit9DmfQ==}
+    peerDependencies:
+      '@vitest/browser': 2.1.9
+      vitest: 2.1.9
+    peerDependenciesMeta:
+      '@vitest/browser':
+        optional: true
+
   '@vitest/coverage-v8@3.2.4':
     resolution: {integrity: sha512-EyF9SXU6kS5Ku/U82E259WSnvg6c8KTjppUncuNdm5QHpe17mwREHnjDzozC8x9MZ0xfBUFSaLkRv4TMA75ALQ==}
     peerDependencies:
@@ -4278,6 +4293,8 @@ snapshots:
       '@babel/helper-string-parser': 7.27.1
       '@babel/helper-validator-identifier': 7.28.5
 
+  '@bcoe/v8-coverage@0.2.3': {}
+
   '@bcoe/v8-coverage@1.0.2': {}
 
   '@cfworker/json-schema@4.1.1': {}
@@ -5385,6 +5402,24 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
+  '@vitest/coverage-v8@2.1.9(vitest@2.1.9(@types/node@25.2.3)(jsdom@25.0.1)(lightningcss@1.30.2))':
+    dependencies:
+      '@ampproject/remapping': 2.3.0
+      '@bcoe/v8-coverage': 0.2.3
+      debug: 4.4.3
+      istanbul-lib-coverage: 3.2.2
+      istanbul-lib-report: 3.0.1
+      istanbul-lib-source-maps: 5.0.6
+      istanbul-reports: 3.2.0
+      magic-string: 0.30.21
+      magicast: 0.3.5
+      std-env: 3.10.0
+      test-exclude: 7.0.2
+      tinyrainbow: 1.2.0
+      vitest: 2.1.9(@types/node@25.2.3)(jsdom@25.0.1)(lightningcss@1.30.2)
+    transitivePeerDependencies:
+      - supports-color
+
   '@vitest/coverage-v8@3.2.4(vitest@3.2.4(@types/node@25.2.3)(jiti@2.6.1)(jsdom@25.0.1)(lightningcss@1.30.2)(tsx@4.21.0)(yaml@2.8.2))':
     dependencies:
       '@ampproject/remapping': 2.3.0