ci: build and test only changed packages and dependants

.github/workflows/lint-build-test.yml

@@ -64,11 +64,13 @@
   validate-changelog:
     name: Validate changelog
     runs-on: ubuntu-latest
-    needs: prepare
+    needs:
+      - prepare
+      - get-changed-packages
     strategy:
       matrix:
         node-version: [24.x]
-        package-name: ${{ fromJson(needs.prepare.outputs.child-workspace-package-names) }}
+        package-name: ${{ fromJson(needs.get-changed-packages.outputs.package-names) }}
     steps:
       - name: Checkout and setup environment
         uses: MetaMask/action-checkout-and-setup@v3
@@ -87,6 +89,57 @@
             exit 1
           fi
 
+  get-changed-packages:
+    name: Get changed packages
+    runs-on: ubuntu-latest
+    needs: prepare
+    outputs:
+      merge-base: ${{ steps.fetch-merge-base.outputs.merge-base }}
+      package-names: ${{ steps.packages.outputs.package-names }}
+    steps:
+      - name: Checkout and setup environment
+        uses: MetaMask/action-checkout-and-setup@v3
+        with:
+          is-high-risk-environment: false
+          persist-credentials: false
+          node-version: 24.x
+      - name: Fetch merge base
+        id: fetch-merge-base
+        if: github.base_ref != '' || github.event.merge_group.base_ref != ''
+        run: |
+          set -euo pipefail
+
+          PREFIXED_REF_REGEX='refs/heads/(.+)'
+          if [[ "$BASE_REF" =~ $PREFIXED_REF_REGEX ]]; then
+            BASE_REF="${BASH_REMATCH[1]}"
+          fi
+
+          MERGE_BASE=$(gh api "repos/$GITHUB_REPOSITORY/compare/$BASE_REF...$HEAD_SHA" --jq '.merge_base_commit.sha')
+          git fetch --unshallow --filter=blob:none --no-tags origin HEAD
+
+          echo "merge-base=$MERGE_BASE" >> "$GITHUB_OUTPUT"
+        env:
+          BASE_REF: ${{ github.event.pull_request.base.ref || github.event.merge_group.base_ref }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha || github.event.merge_group.head_sha }}
+          GH_TOKEN: ${{ github.token }}
+      - name: Get changed package names
+        id: packages
+        run: |
+          if [[ -n "$MERGE_BASE" ]]; then
+            PACKAGES=$(yarn tsx scripts/get-changed-workspaces.mts "$MERGE_BASE" "$HEAD_SHA")
+            # Fall back to all packages if no packages changed (e.g. CI-only PRs),
+            # to ensure required status checks are not skipped.
+            if [[ "$PACKAGES" == "[]" ]]; then
+              PACKAGES=$(yarn workspaces list --no-private --json | jq --slurp --raw-output 'map(.name) | @json')
+            fi
+          else
+            PACKAGES=$(yarn workspaces list --no-private --json | jq --slurp --raw-output 'map(.name) | @json')
+          fi
+          echo "package-names=$PACKAGES" >> "$GITHUB_OUTPUT"
+        env:
+          MERGE_BASE: ${{ steps.fetch-merge-base.outputs.merge-base }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha || github.event.merge_group.head_sha }}
+
   validate-changelog-diffs:
     name: Validate changelog diffs
     if: github.event_name == 'pull_request' || github.event_name == 'merge_group'
@@ -102,7 +155,9 @@
   build:
     name: Build
     runs-on: ubuntu-latest
-    needs: prepare
+    needs:
+      - prepare
+      - get-changed-packages
     strategy:
       matrix:
         node-version: [24.x]
@@ -113,7 +168,28 @@
           is-high-risk-environment: false
           persist-credentials: false
           node-version: ${{ matrix.node-version }}
-      - run: yarn build
+      - name: Unshallow checkout
+        if: needs.get-changed-packages.outputs.merge-base != ''
+        run: |
+          # Unshallow so git can walk history back to the merge base for
+          # `git diff --name-only`. Using `--filter=blob:none` avoids
+          # downloading file content — only commit and tree objects are needed.
+          git fetch --unshallow --filter=blob:none --no-tags origin HEAD
+      - name: Build
+        run: |
+          if [[ -n "$MERGE_BASE" ]]; then
+            TSCONFIG=$(mktemp --tmpdir="$GITHUB_WORKSPACE" --suffix=.json)
+            yarn tsx scripts/generate-partial-build-tsconfig.mts "$MERGE_BASE" "$HEAD_SHA" > "$TSCONFIG"
+            if [[ -s "$TSCONFIG" ]]; then
+              yarn ts-bridge --project "$TSCONFIG" --verbose
+            fi
+            rm -f "$TSCONFIG"
+          else
+            yarn build
+          fi
+        env:
+          MERGE_BASE: ${{ needs.get-changed-packages.outputs.merge-base }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha || github.event.merge_group.head_sha }}
       - name: Require clean working directory
         shell: bash
         run: |
@@ -151,10 +227,12 @@
   test-18:
     name: Test (18.x)
     runs-on: ubuntu-latest
-    needs: prepare
+    needs:
+      - prepare
+      - get-changed-packages
     strategy:
       matrix:
-        package-name: ${{ fromJson(needs.prepare.outputs.child-workspace-package-names) }}
+        package-name: ${{ fromJson(needs.get-changed-packages.outputs.package-names) }}
     steps:
       - name: Checkout and setup environment
         uses: MetaMask/action-checkout-and-setup@v3
@@ -176,10 +254,12 @@
   test-20:
     name: Test (20.x)
     runs-on: ubuntu-latest
-    needs: prepare
+    needs:
+      - prepare
+      - get-changed-packages
     strategy:
       matrix:
-        package-name: ${{ fromJson(needs.prepare.outputs.child-workspace-package-names) }}
+        package-name: ${{ fromJson(needs.get-changed-packages.outputs.package-names) }}
     steps:
       - name: Checkout and setup environment
         uses: MetaMask/action-checkout-and-setup@v3
@@ -201,10 +281,12 @@
   test-22:
     name: Test (22.x)
     runs-on: ubuntu-latest
-    needs: prepare
+    needs:
+      - prepare
+      - get-changed-packages
     strategy:
       matrix:
-        package-name: ${{ fromJson(needs.prepare.outputs.child-workspace-package-names) }}
+        package-name: ${{ fromJson(needs.get-changed-packages.outputs.package-names) }}
     steps:
       - name: Checkout and setup environment
         uses: MetaMask/action-checkout-and-setup@v3

scripts/generate-partial-build-tsconfig.mts

@@ -0,0 +1,50 @@
+import {
+  getTypeScriptWorkspaces,
+  computeChangedWorkspaces,
+} from './lib/workspaces.mjs';
+
+/**
+ * Generate a filtered tsconfig.build.json for partial CI builds.
+ *
+ * Given a merge base SHA, outputs a tsconfig that references only the
+ * TypeScript packages that changed since that commit plus their transitive
+ * dependants and dependencies. Pipe the output to a temp file and pass it
+ * to `ts-bridge --project`.
+ *
+ * Dependencies are always included because TypeScript project references
+ * require every referenced project's dist output to already exist on disk.
+ *
+ * Usage: `tsx scripts/generate-partial-build-tsconfig.mts <merge-base-sha> [<head-sha>]`
+ */
+async function main() {
+  const mergeBase = process.argv[2];
+  if (!mergeBase) {
+    console.error(
+      'Usage: generate-partial-build-tsconfig.mts <merge-base-sha> [<head-sha>]',
+    );
+    process.exitCode = 1;
+    return;
+  }
+
+  const headRef = process.argv[3] ?? 'HEAD';
+
+  const workspaces = await getTypeScriptWorkspaces();
+  const packagesToBuild = await computeChangedWorkspaces(
+    workspaces,
+    mergeBase,
+    headRef,
+    true,
+  );
+
+  const references = workspaces
+    .filter(({ name }) => packagesToBuild.has(name))
+    .map(({ location }) => ({ path: `./${location}/tsconfig.build.json` }));
+
+  if (references.length === 0) {
+    return;
+  }
+
+  console.log(JSON.stringify({ files: [], include: [], references }, null, 2));
+}
+
+await main();

scripts/get-changed-workspaces.mts

@@ -0,0 +1,43 @@
+import {
+  getAllWorkspaces,
+  computeChangedWorkspaces,
+} from './lib/workspaces.mjs';
+
+/**
+ * List workspace package names that need to be checked given a merge base.
+ *
+ * Outputs a JSON array of package names to stdout. Always includes packages
+ * that changed since the merge base plus their transitive dependants. Pass
+ * `--include-dependencies` to also include transitive dependencies (needed
+ * for TypeScript project reference builds where dist outputs must exist).
+ *
+ * Usage: `tsx scripts/get-changed-workspaces.mts <merge-base-sha> [<head-sha>] [--include-dependencies]`
+ */
+const args = process.argv.slice(2);
+const includeDependencies = args.includes('--include-dependencies');
+const positional = args.filter((arg) => !arg.startsWith('--'));
+
+const mergeBase = positional[0];
+if (!mergeBase) {
+  console.error(
+    'Usage: get-changed-workspaces.mts <merge-base-sha> [<head-sha>] [--include-dependencies]',
+  );
+  process.exitCode = 1;
+  process.exit();
+}
+
+const headRef = positional[1] ?? 'HEAD';
+
+const workspaces = await getAllWorkspaces();
+const changed = await computeChangedWorkspaces(
+  workspaces,
+  mergeBase,
+  headRef,
+  includeDependencies,
+);
+
+const names = workspaces
+  .filter(({ name }) => changed.has(name))
+  .map(({ name }) => name);
+
+console.log(JSON.stringify(names));