Add retry to running demo projects for macOs platforms in CI

.github/other/retry.sh

@@ -15,7 +15,8 @@ for ((attempt=0; attempt<limit; attempt++)); do
     if "$@"; then
         # Command succeeded, exit the loop
         echo "Done."
-        break
+        # Exit with success status code.
+        exit 0
     fi
 
     # Calculate the sleep duration using the retry interval from the array
@@ -26,3 +27,7 @@ for ((attempt=0; attempt<limit; attempt++)); do
     echo "Retry #$attempt in $sleepDuration seconds..."
     sleep "$sleepDuration"
 done
+
+echo "Failed to execute command '$1'."
+# Exit with an error code.
+exit 1

.github/workflows/ci.yml

@@ -151,15 +151,20 @@ jobs:
         include:
           # macOS
 
+          # macOS builds fail semi-randomly with an `libc++abi: Pure virtual function called!` error.
+          # For now on run them with retry; resort to compiling only if it won't be enough (i.e. first time when it will fail three times in the row).
+          # See: https://github.com/godot-rust/demo-projects/issues/12
           - name: macos-x86
             os: macos-13
             artifact-name: macos-x86-nightly
             godot-binary: godot.macos.editor.dev.x86_64
+            retry: true
 
           - name: macos-arm
             os: macos-latest
             artifact-name: macos-arm-nightly
             godot-binary: godot.macos.editor.dev.arm64
+            retry: true
 
           # Windows
 
@@ -214,17 +219,25 @@ jobs:
         run: cargo build --release ${{ matrix.rust-extra-args }}
 
       - name: "Run examples for short time"
+        env:
+          RETRY: ${{ matrix.retry }}
         run: |
           # Enable extended globbing to allow pattern exclusion.
           shopt -s extglob
 
           # Match all directories/files except `target` and any starting with `.`.
           files='!(target|.*)/'
-
+          if [[ $RETRY == "true" ]]; then
+            # macOS – retry running demo projects several times on fail.
+            echo "Running examples with retry"
+            RETRY_CMD="./.github/other/retry.sh"
+          else
+            RETRY_CMD=""
+          fi
           # List all folders in current directory. Don't quote $files variable.
           for demo in $files; do
             # Strip trailing '/' from folder name.
-          	./.github/other/check-example.sh "${demo%/}"
+            $RETRY_CMD ./.github/other/check-example.sh "${demo%/}"
           done