Seems like a gunzip cpio problem

.ci/package-mac.sh

@@ -16,16 +16,15 @@ set -e
 # Modify the package with the solution from https://stackoverflow.com/a/11299907
 # First, download the package and extract it
 wget https://github.com/rime/squirrel/releases/download/${SQUIRREL_VERSION}/Squirrel-${SQUIRREL_VERSION}.pkg
+pkgutil --expand Squirrel-${SQUIRREL_VERSION}.pkg package
+pushd package
 
 # Extract the application
-mkdir package
-pushd package
-xar -xf ../Squirrel-${SQUIRREL_VERSION}.pkg
-cat Payload | gunzip -dc | cpio -i
+tar --xattrs -xzf Payload
+pushd Squirrel.app/Contents
 
 # Remove all default rime schemas but keep opencc data and app config
 # Then, download the latest schemas we need and amend the `default.yaml`
-pushd Squirrel.app/Contents
 GLOBIGNORE=SharedSupport/squirrel.yaml
 rm SharedSupport/*.*
 cp -rf "$SCHEMA_DIR/"* SharedSupport
@@ -35,16 +34,16 @@ popd
 codesign --sign "Developer ID Application: $APPLE_DEVELOPER_NAME ($APPLE_DEVELOPER_TEAM_ID)" --timestamp --deep --force --options runtime --preserve-metadata=identifier,entitlements Squirrel.app
 
 # Compress back the application
-find Squirrel.app | cpio -o | gzip -c > Payload
+tar --xattrs -czf Payload Squirrel.app
 mkbom Squirrel.app Bom
 rm -rf Squirrel.app
+popd
 
 # Finally, compress back the package
-mkdir ../output
-xar -cf ../output/Squirrel.pkg *
-popd
+mkdir output
+pkgutil --flatten package output/Squirrel.pkg
+cd output
 
 # Resign the package
-cd output
 pkg_path=Squirrel-${SQUIRREL_VERSION}-rime-cantonese.pkg
 productsign --sign "Developer ID Installer: $APPLE_DEVELOPER_NAME ($APPLE_DEVELOPER_TEAM_ID)" Squirrel.pkg "$pkg_path"