Repository: electron/electron
Pull request: build: set the minimum macOS SDK to 10.15

#### Description of Change

An unfortunate side effect of a recent Chrome roll was 6493969: Update mac_sdk_min to
match minimum required SDK version | https://chromium-review.googlesource.com/c/chromium/src/+/6493969, which bumped the required minimum macOS SDK version to 15, and bumped our required runners to use `macos-15-xlarge`, which is now running out of space on publish.

This PR is meant to unblock nightlies and get our builds back up and running while we fix this issue upstream and/or reduce space on the runners themselves.

#### Checklist
<!-- Remove items that do not apply. For completed items, change [ ] to [x]. -->

- [x] PR description included and stakeholders cc'd
- [x] `npm test` passes
- [x] tests are [changed or added](https://github.com/electron/electron/blob/main/docs/development/testing.md)
- [x] relevant API documentation, tutorials, and examples are updated and follow the [documentation style guide](https://github.com/electron/electron/blob/main/docs/development/style-guide.md)
- [x] [PR release notes](https://github.com/electron/clerk/blob/main/README.md) describe the change in a way relevant to app developers, and are [capitalized, punctuated, and past tense](https://github.com/electron/clerk/blob/main/README.md#examples).

#### Release Notes

Notes: none


Changed files:
filename: .github/workflows/build.yml
patch: @@ -184,7 +184,7 @@ jobs:
     with:
       target-platform: macos
       target-archs: x64 arm64
-      check-runs-on: macos-15
+      check-runs-on: macos-14
       gn-build-type: testing
     secrets: inherit
 
@@ -219,7 +219,7 @@ jobs:
     uses: ./.github/workflows/pipeline-electron-build-and-test.yml
     needs: checkout-macos
     with:
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       test-runs-on: macos-13
       target-platform: macos
       target-arch: x64
@@ -237,7 +237,7 @@ jobs:
     uses: ./.github/workflows/pipeline-electron-build-and-test.yml
     needs: checkout-macos
     with:
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       test-runs-on: macos-14
       target-platform: macos
       target-arch: arm64

filename: .github/workflows/macos-publish.yml
patch: @@ -47,7 +47,7 @@ jobs:
     needs: checkout-macos
     with:
       environment: production-release
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       target-platform: macos
       target-arch: x64
       target-variant: darwin
@@ -62,7 +62,7 @@ jobs:
     needs: checkout-macos
     with:
       environment: production-release
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       target-platform: macos
       target-arch: x64
       target-variant: mas
@@ -77,7 +77,7 @@ jobs:
     needs: checkout-macos
     with:
       environment: production-release
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       target-platform: macos
       target-arch: arm64
       target-variant: darwin
@@ -92,7 +92,7 @@ jobs:
     needs: checkout-macos
     with:
       environment: production-release
-      build-runs-on: macos-15-xlarge
+      build-runs-on: macos-14-xlarge
       target-platform: macos
       target-arch: arm64
       target-variant: mas

filename: patches/chromium/.patches
patch: @@ -135,3 +135,4 @@ refactor_patch_electron_permissiontypes_into_blink.patch
 revert_views_remove_desktopwindowtreehostwin_window_enlargement.patch
 build_partial_revert_mac_fullscreen_top_chrome_mouse_events.patch
 revert_update_siso-chromium_image.patch
+build_set_mac_sdk_minimum_to_10.patch

filename: patches/chromium/build_set_mac_sdk_minimum_to_10.patch
patch: @@ -0,0 +1,26 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Keeley Hammond <khammond@slack-corp.com>
+Date: Tue, 1 Jul 2025 15:40:02 -0700
+Subject: build: Set MacOS SDK minimum back to 10
+
+This commit reverts 6493969: Update mac_sdk_min to
+match minimum required SDK version |
+https://chromium-review.googlesource.com/c/chromium/src/+/6493969
+
+This patch is purely to unblock nightlies while
+we merge an upstream fix and allocate additional space
+on the Mac runners. If this patch is still in main
+anytime after July 30, 2025, find @VerteDinde and yell
+at her.
+
+diff --git a/build/config/mac/mac_sdk_overrides.gni b/build/config/mac/mac_sdk_overrides.gni
+index 8f8ac1c218ce15fa5c1aecbbcd0b93281f6c52f2..15ddfd5cffbaba0704b3217e1ae4f2825f399d96 100644
+--- a/build/config/mac/mac_sdk_overrides.gni
++++ b/build/config/mac/mac_sdk_overrides.gni
+@@ -7,5 +7,5 @@
+ 
+ declare_args() {
+   # Minimum supported version of the Mac SDK.
+-  mac_sdk_min = "15"
++  mac_sdk_min = "10.15"
+ }