From b9d630edbc5091c4bbe5946511d23da17a51bf09 Mon Sep 17 00:00:00 2001
From: Jelle Raaijmakers <jelle@ladybird.org>
Date: Fri, 20 Jun 2025 16:01:09 +0200
Subject: [PATCH] CI: Trigger Windows build on PR label 'windows'

Our CI matrix now includes Windows if the 'windows' label is added to
the PR. The job still takes too long to include it for every PR, but it
is certainly useful to have it run on Windows-specific PRs and PRs that
might break Windows builds.
---
 .github/workflows/ci.yml | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index df29187b46d..327d3b3646a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,13 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - labeled
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || format('{0}-{1}', github.ref, github.run_number) }}
@@ -9,7 +16,9 @@ concurrency:
 jobs:
   # CI matrix - runs the job in lagom-template.yml with different configurations.
   Lagom:
-    if: github.repository == 'LadybirdBrowser/ladybird'
+    if: |
+      github.repository == 'LadybirdBrowser/ladybird'
+      && (github.event_name != 'pull_request' || github.event.action != 'labeled' || github.event.label.name == 'windows')
     name: ${{ matrix.os_name }}, ${{ matrix.arch }}, ${{ matrix.build_preset }}, ${{ matrix.toolchain }}
 
     strategy:
@@ -44,6 +53,17 @@ jobs:
             clang_plugins: false
             runner_labels: '["blacksmith-16vcpu-ubuntu-2404"]'
 
+          - os_name: 'Windows'
+            arch: 'x86_64'
+            build_preset: 'Windows_Sanitizer_CI'
+            toolchain: 'ClangCL'
+            clang_plugins: false
+            runner_labels: '["windows-2025"]'
+
+        exclude:
+          # Exclude the Windows build from the matrix if the PR is not labeled with 'windows'.
+          - os_name: ${{ !contains(github.event.pull_request.labels.*.name, 'windows') && 'Windows' }}
+
     uses: ./.github/workflows/lagom-template.yml
     with:
       toolchain: ${{ matrix.toolchain }}