Implement a workaround for macOS/Bazel flakes.

See bazelbuild/bazel#17437 for more details.

PiperOrigin-RevId: 509869860

.github/actions/bazel/action.yml

@@ -98,6 +98,17 @@ runs:
       run: ${{ inputs.bash }}
       shell: bash
 
+    # Xcode has a warmup period that can frequently exceed the 2m timeout
+    # that Bazel uses internally.  If we warm it up in advance w/o a timeout,
+    # Bazel's call will run in seconds.
+    # See https://github.com/bazelbuild/bazel/issues/17437 for more details.
+    - name: Warm up Xcode
+      if: ${{ runner.os == 'macOS' }}
+      shell: bash
+      run: |
+        bazelisk build @bazel_tools//tools/osx:xcode_locator.m
+        time xcrun --sdk macosx clang -mmacosx-version-min=10.9 -fobjc-arc -framework CoreServices -framework Foundation -o xcode-locator-bin $(bazel info output_base)/external/bazel_tools/tools/osx/xcode_locator.m
+
     - name: Run Bazel
       if: ${{ !inputs.bash }}
       run: >-

.github/actions/internal/bazel-setup/action.yml

@@ -42,7 +42,9 @@ runs:
     - name: Initialize MacOS-specific Bazel flags
       if: runner.os == 'macOS'
       shell: bash
-      run: echo "BAZEL_FLAGS=$BAZEL_FLAGS --xcode_version_config=//.github:host_xcodes" >> $GITHUB_ENV
+      run: |
+        echo "BAZEL_FLAGS=$BAZEL_FLAGS --xcode_version_config=//.github:host_xcodes" >> $GITHUB_ENV
+        echo "DEVELOPER_DIR=${{ env.DEVELOPER_DIR || '/Applications/Xcode_14.1.app/Contents/Developer' }}" >> $GITHUB_ENV
 
     - name: Configure Bazel caching
       # Skip bazel cache for local act runs due to issue with credential files