Summary:
This addesses a few issues I noticed while migrating my app to the new build-time codegen on iOS.
1. I noticed random failures because of codegen on iOS. This is mostly due to the fact the codegen output files are not specified in the xcode script. The only reason it works relatively fine currently is because the codegen output is inside the input files directory. This has the side effect of causing files to be regenerated every build, then causes all core modules to be recompiled which adds up a significant amount of time to rebuilds. To fix this I added the generated files to the script phase output and moved the FBReactNativeSpec dir outside of the codegen source (Libraries). I moved it to the React directory as this seemed to make sense and is where a lot of iOS files are as well as the core modules. Note this might require internal changes. This removes the circular dependency between our build phase input and output so consecutive builds can be cached properly.
2. Add `set -o pipefail` to the xcode script, this helped propagate errors properly to xcode because of the `| tee` pipe so it fails at the script phase and not later with a header not found error. Also add `2>&1` to pipe stderr to stdout so errors are also captured in the log file.
3. Add the `-l` flag to the bash invocation to help finding the yarn binary. With my setup yarn is added to the system PATH in my user .profile. Adding this file will cause bash to source the user environment which xcode scripts does not by default. I think this will help with most setups.
4. If yarn is not found the `command -v yarn` would make the script exit without any output because of the -e flag. I made a change to ignore the return code and check later if YARN_BINARY is set and have an explicit error message if not.
## Changelog
[iOS] [Fixed] - Make codegen more reliable on iOS
Pull Request resolved: https://github.com/facebook/react-native/pull/30792
Test Plan:
Tested various project states to make sure the build always succeeds in RN tester:
- Simulate fresh clone, remove all ignored files, install pods, build
- Build, delete FBReactNativeSpec generated files, build again
- Build, build again, make sure FBReactNativeSpec is cached and not rebuilt
- Make the script fail and check that xcode shows the script error logs properly
Note: Did not test fabric
Reviewed By: fkgozali
Differential Revision: D26104213
Pulled By: hramos
fbshipit-source-id: e18d9a0b9ada7c0c2e608d29ffe88087f04605b4
Peter Argany
Janic Duplessis
