Dynamically resolve simulator destinations in CI

Replace hardcoded simulator names and OS versions with dynamic
discovery using xcrun simctl. Each simulator platform job now
queries available devices at runtime and picks the first match,
making CI resilient to runner image changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: BrentMifsud

.github/workflows/ci.yaml

@@ -23,16 +23,16 @@ jobs:
             command: swift test
           - platform: iOS
             runner: macos-latest
-            command: xcodebuild test -scheme Simplicity -destination "platform=iOS Simulator,name=iPhone 17" -skipPackagePluginValidation
+            sim_runtime: iOS
           - platform: tvOS
             runner: macos-latest
-            command: xcodebuild test -scheme Simplicity -destination "platform=tvOS Simulator,name=Apple TV 4k (3rd generation)" -skipPackagePluginValidation
+            sim_runtime: tvOS
           - platform: watchOS
             runner: macos-latest
-            command: xcodebuild test -scheme Simplicity -destination "platform=watchOS Simulator,name=Apple Watch Ultra 3 (49mm)" -skipPackagePluginValidation
+            sim_runtime: watchOS
           - platform: visionOS
             runner: macos-latest
-            command: xcodebuild test -scheme Simplicity -destination "platform=visionOS Simulator,name=Apple Vision Pro" -skipPackagePluginValidation
+            sim_runtime: visionOS
           - platform: Linux
             runner: ubuntu-latest
             container: swift:6.2
@@ -59,5 +59,37 @@ jobs:
         if: ${{ matrix.runner == 'macos-latest' }}
         run: xcodebuild -version
 
+      - name: Resolve simulator destination
+        if: ${{ matrix.sim_runtime }}
+        run: |
+          RUNTIME="${{ matrix.sim_runtime }}"
+          # visionOS runtimes may use 'xrOS' in the identifier
+          case "$RUNTIME" in
+            visionOS) PATTERN="visionOS|xrOS" ;;
+            *) PATTERN="$RUNTIME" ;;
+          esac
+
+          DEVICE_INFO=$(xcrun simctl list devices available -j | jq -r --arg p "$PATTERN" '
+            [.devices | to_entries[] | select(.key | test($p)) | .value[] | select(.isAvailable == true)]
+            | first | "\(.udid)|\(.name)"
+          ')
+
+          DEVICE_UDID="${DEVICE_INFO%%|*}"
+          DEVICE_NAME="${DEVICE_INFO##*|}"
+
+          if [ "$DEVICE_UDID" = "null" ] || [ -z "$DEVICE_UDID" ]; then
+            echo "::error::No available ${{ matrix.sim_runtime }} simulator found"
+            xcrun simctl list devices available
+            exit 1
+          fi
+
+          echo "Resolved simulator: $DEVICE_NAME ($DEVICE_UDID)"
+          echo "SIM_DESTINATION=platform=${{ matrix.sim_runtime }} Simulator,id=$DEVICE_UDID" >> "$GITHUB_ENV"
+
       - name: Run tests
-        run: ${{ matrix.command }}
+        run: |
+          if [ -n "$SIM_DESTINATION" ]; then
+            xcodebuild test -scheme Simplicity -destination "$SIM_DESTINATION" -skipPackagePluginValidation
+          else
+            ${{ matrix.command }}
+          fi