cannot build react native project after react-native-git-upgrade - react-native

Question

I tried to upgrade react-native from 0.49.3 to 0.55.3. I followed the official [guide][1] and when I ran react-native-git-upgrade, I got the following log:
git-upgrade info Check for updates
git-upgrade info Using yarn 1.5.1
git-upgrade info Read package.json files
git-upgrade info Check declared version
git-upgrade info Check matching versions
git-upgrade info Check React peer dependency
git-upgrade info Check that Git is installed
git-upgrade info Get information from NPM registry
git-upgrade info Upgrading to React Native 0.55.3, React 16.3.1
git-upgrade info Setup temporary working directory
git-upgrade info Configure Git environment
git-upgrade info Init Git repository
git-upgrade info Add all files to commit
git-upgrade info Commit current project sources
git-upgrade info Create a tag before updating sources
git-upgrade info Generate old version template
git-upgrade info Add updated files to commit
git-upgrade info Commit old version template
git-upgrade info Install the new version
warning " > react-native-maps#0.20.1" has incorrect peer dependency "react#16.0.0".
warning " > react-native-maps#0.20.1" has incorrect peer dependency "react-native#0.51.0".
warning " > #storybook/addon-storyshots#3.2.13" has unmet peer dependency "#storybook/addons#^3.2.13".
warning " > #storybook/addon-storyshots#3.2.13" has unmet peer dependency "#storybook/channels#^3.2.13".
warning " > #storybook/addon-storyshots#3.2.13" has unmet peer dependency "#storybook/react#^3.2.13".
warning " > #storybook/addon-storyshots#3.2.13" has unmet peer dependency "babel-core#^6.26.0".
warning "#storybook/react-native > #storybook/ui > react-icons#2.2.7" has incorrect peer dependency "react-dom#^0.14.0 || ^15.0.0 || ^16.0.0".
warning "#storybook/react-native > #storybook/ui > react-komposer#2.0.0" has incorrect peer dependency "react#^0.14.7 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > react-modal#2.4.1" has incorrect peer dependency "react#^0.14.0 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > react-modal#2.4.1" has incorrect peer dependency "react-dom#^0.14.0 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > react-treebeard#2.0.3" has incorrect peer dependency "react#^15.5.4".
warning "#storybook/react-native > #storybook/ui > react-treebeard#2.0.3" has incorrect peer dependency "react-dom#^15.5.4".
warning "#storybook/react-native > #storybook/ui > mantra-core > react-komposer#1.13.1" has incorrect peer dependency "react#^0.14.3 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > mantra-core > react-simple-di#1.2.0" has incorrect peer dependency "react#^0.14.0 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > react-komposer > react-stubber#1.0.0" has incorrect peer dependency "react#^0.14.7 || ^15.0.0".
warning "#storybook/react-native > #storybook/ui > react-treebeard > velocity-react#1.3.3" has incorrect peer dependency "react-dom#^15.3.0 || ^16.0.0".
warning "#storybook/react-native > #storybook/ui > react-treebeard > velocity-react > react-transition-group#1.2.1" has incorrect peer dependency "react-dom#^15.0.0 || ^16.0.0".
warning " > babel-jest#21.2.0" has unmet peer dependency "babel-core#^6.0.0 || ^7.0.0-alpha || ^7.0.0-beta || ^7.0.0".
warning " > enzyme#2.9.1" has incorrect peer dependency "react#0.13.x || 0.14.x || ^15.0.0-0 || 15.x".
warning " > react-addons-test-utils#15.4.2" has incorrect peer dependency "react-dom#^15.4.2".
warning "react-native > eslint-plugin-react-native#3.2.1" has unmet peer dependency "eslint#^3.17.0 || ^4.0.0".
git-upgrade info Generate new version template
git-upgrade info Add updated files to commit
git-upgrade info Commit new version template
git-upgrade info Generate the patch between the 2 versions
git-upgrade info Save the patch in temp directory
git-upgrade info Reset the 2 temporary commits
git-upgrade info Apply the patch
error: patch failed: .gitignore:51
Falling back to three-way merge...
Applied patch to '.gitignore' with conflicts.
error: ios/MyApp.xcodeproj/project.pbxproj: does not exist in index
error: ios/MyApp/AppDelegate.h: does not exist in index
error: ios/MyApp/AppDelegate.m: does not exist in index
error: ios/MyApp/main.m: does not exist in index
error: ios/MyAppTests/MyAppTests.m: does not exist in index
git-upgrade WARN The upgrade process succeeded but there might be conflicts to be resolved. See above for the list of files that have merge conflicts.
git-upgrade info Upgrade done
Notice these lines:
error: ios/MyApp.xcodeproj/project.pbxproj: does not exist in index
error: ios/MyApp/AppDelegate.h: does not exist in index
error: ios/MyApp/AppDelegate.m: does not exist in index
error: ios/MyApp/main.m: does not exist in index
error: ios/MyAppTests/MyAppTests.m: does not exist in index
These files are now all missing. Despite the message saying it succeeded, trying react-native -v yields
react-native-cli: 2.0.1
react-native: 0.55.3
And now the MyApp/ios/ directory is missing almost all of it's original files. If I even try react-native run-ios, I get xcodebuild: error: Scheme MyApp is not currently configured for the build action. Any suggestions would be incredibly helpful.

Answer 1

Figured it out. For those of you with this problem, all you need to do is delete your android/ios folder and use react-native eject which will regenerate the files necessary to rebuild your react-native project. This should be in the official react native upgrading guide IMO.