From 052b5f5bf0dd76bc3bc51fde3e704b5de0ffd9df Mon Sep 17 00:00:00 2001
From: Pyseph <45090858+Pyseph@users.noreply.github.com>
Date: Wed, 4 Nov 2026 16:09:44 +0100
Subject: [PATCH] perf(ci): split Test Web over two runners with vitest --shard

Test Web is the longest job of web pull requests; vitest --shard halves its files per runner.
The boot step runs on shard 1 only; Check still gates on test_web as a whole.
---
 .github/workflows/ci.yml | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dc12d15d17860..b79485088dd11 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -287,16 +287,25 @@ jobs:
 
   # The web suite is the largest outside the server. In the shared Test job it
   # started last and ran alone for about 40s after everything else finished.
-  # release.yml mirrors this test, test_web, and test_server split.
+  # It is also the longest job of web pull requests, so vitest's `--shard` splits
+  # its test files (unit and browser alike, by a hash of the path) over two
+  # runners. The shards repeat only checkout, install and the Chromium restore,
+  # about 20s. The `Check` job needs `test_web` as a whole, so this adds no
+  # required status. release.yml mirrors the test, test_web, and test_server
+  # split but not the web shards: it is not a pull request wait.
   test_web:
     permissions:
       contents: read
       id-token: write
-    name: Test Web
+    name: Test Web ${{ matrix.shard }}
     needs: changes
     if: ${{ !cancelled() && needs.changes.outputs.test_web != 'false' }}
     runs-on: blacksmith-8vcpu-ubuntu-2404
     timeout-minutes: 10
+    strategy:
+      fail-fast: false
+      matrix:
+        shard: [1, 2]
     steps:
       - name: Checkout
         uses: actions/checkout@v6
@@ -338,10 +347,12 @@ jobs:
           fi
 
       - name: Test
-        run: vp run --filter @t3tools/web test
+        run: vp run --filter @t3tools/web test --shard ${{ matrix.shard }}/${{ strategy.job-total }}
 
       # Browser tests run source modules; this boots the production chunk graph.
+      # One shard runs it: the build does not depend on which test files ran.
       - name: Boot the built web client
+        if: matrix.shard == 1
         run: |
           vp run --filter @t3tools/web build
           node apps/web/scripts/verify-built-boot.ts