ensure iOS config plugin is idempotent

packages/plugin-expo-eas-sourcemaps/src/ios.js

@@ -26,17 +26,24 @@ function withIosPlugin (config, onPremConfig) {
 
     const additionalExports = '"export EXTRA_PACKAGER_ARGS=\\"--sourcemap-output $TMPDIR/$(md5 -qs \\"$CONFIGURATION_BUILD_DIR\\")-main.jsbundle.map\\"\\n'
 
-    const modifiedScript = additionalExports + initialScript.substr(1)
-
-    bundleReactNativePhase.shellScript = modifiedScript
+    if (!initialScript.indexOf(additionalExports) < 0) {
+      const modifiedScript = additionalExports + initialScript.substr(1)
+      bundleReactNativePhase.shellScript = modifiedScript
+    }
 
     // 03. Configure the new build phase
-    const shellScript = 'SOURCE_MAP="$TMPDIR/$(md5 -qs "$CONFIGURATION_BUILD_DIR")-main.jsbundle.map" ../node_modules/@bugsnag/plugin-expo-eas-sourcemaps/lib/bugsnag-expo-xcode.sh'
+    const uploadBuildPhaseComment = 'Upload source maps to Bugsnag'
 
-    xcodeProject.addBuildPhase([], buildPhaseName, 'Upload source maps to Bugsnag', null, {
-      shellPath: '/bin/sh',
-      shellScript: shellScript
-    })
+    const uploadBuildPhase = xcodeProject.pbxItemByComment(uploadBuildPhaseComment, buildPhaseName)
+
+    if( !uploadBuildPhase ) {
+      const shellScript = 'SOURCE_MAP="$TMPDIR/$(md5 -qs "$CONFIGURATION_BUILD_DIR")-main.jsbundle.map" ../node_modules/@bugsnag/plugin-expo-eas-sourcemaps/lib/bugsnag-expo-xcode.sh'
+
+      xcodeProject.addBuildPhase([], buildPhaseName, uploadBuildPhaseComment, null, {
+        shellPath: '/bin/sh',
+        shellScript: shellScript
+      })
+    }
 
     return config
   })