From eedfe98de9ff3e7fc0e62d755592da8e1a4112b5 Mon Sep 17 00:00:00 2001
From: derrickfink <derrickfink@boisestate.edu>
Date: Mon, 14 Sep 2026 18:22:39 -0600
Subject: [PATCH] perf(ci): infra jest transpile-only + shared tsc type-check
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Make ts-jest transpile-only (isolatedModules) so jest workers stop re-type-checking the whole project each — the dominant cost of the infra suite (the long pole once backend went parallel in #1111). Add a single 'tsc --noEmit' (npm run build) step to the infra CI job so type safety is preserved on PRs (previously only ts-jest enforced it; tsc ran only in teardown.yml). Workers stay at 2 (the --maxWorkers bump regressed 2.5x in #1112). No const enum in the tree, so isolatedModules is safe. Verified: tsc clean; 178 tests green transpile-only.
---
 .github/workflows/tests.yml   | 6 ++++++
 infrastructure/jest.config.js | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a53a08d26..7dea55e10 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -154,6 +154,12 @@ jobs:
       - name: Install
         working-directory: infrastructure
         run: npm ci --prefer-offline
+      - name: Type-check (tsc --noEmit)
+        working-directory: infrastructure
+        # Single shared type-check for the whole project. jest now transpiles
+        # only (isolatedModules), so this is where infra type errors are caught
+        # on a PR — cheaper once here than re-run inside every jest worker.
+        run: npm run build
       - name: Run tests
         working-directory: infrastructure
         run: npx jest --maxWorkers=2
diff --git a/infrastructure/jest.config.js b/infrastructure/jest.config.js
index e9a420407..15b3c4cbb 100644
--- a/infrastructure/jest.config.js
+++ b/infrastructure/jest.config.js
@@ -4,6 +4,12 @@ module.exports = {
   testMatch: ['**/*.test.ts'],
   transform: {
     '^.+\\.tsx?$': ['ts-jest', {
+      // Transpile-only: skip per-worker type-checking (each jest worker
+      // otherwise re-type-checks the whole project with no shared cache, the
+      // dominant cost of this suite). Type safety is enforced once by the
+      // `tsc --noEmit` step in the CI job (.github/workflows/tests.yml) and by
+      // `npm run build` locally. Safe here: no `const enum` in the tree.
+      isolatedModules: true,
       diagnostics: {
         ignoreCodes: [151002],
       },