`build()` goes in OOM when rewriting the RNTesterPods xcodeproject

[cipolleschi]

Hey there!

I was trying to use this amazing package to do some manipulation to the RNTesterPods project, in the React Native repository.

As you know, we are moving away from Cocoapods toward SwiftPM, but we still need a solution to modify the Xcode project.

The problem I'm facing is that the build function goes in OOM when trying to create the String representation of the RNTesterPods project.

This is the full stack trace:

<--- Last few GCs --->

[32490:0x130008000]    20341 ms: Scavenge (interleaved) 4043.1 (4121.6) -> 4043.0 (4122.6) MB, pooled: 0 MB, 10.00 / 0.00 ms  (average mu = 0.121, current mu = 0.058) allocation failure; 
[32490:0x130008000]    20431 ms: Scavenge (interleaved) 4044.1 (4122.6) -> 4044.1 (4145.3) MB, pooled: 0 MB, 90.04 / 0.00 ms  (average mu = 0.121, current mu = 0.058) allocation failure; 


<--- JS stacktrace --->

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
----- Native stack trace -----

 1: 0x1042ef484 node::OOMErrorHandler(char const*, v8::OOMDetails const&) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 2: 0x1044b5a48 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, v8::OOMDetails const&) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 3: 0x1046c39a0 v8::internal::Heap::stack() [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 4: 0x1046c1d40 v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 5: 0x1046b6328 v8::internal::HeapAllocator::AllocateRawWithLightRetrySlowPath(int, v8::internal::AllocationType, v8::internal::AllocationOrigin, v8::internal::AllocationAlignment) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 6: 0x1046b6b60 v8::internal::HeapAllocator::AllocateRawWithRetryOrFailSlowPath(int, v8::internal::AllocationType, v8::internal::AllocationOrigin, v8::internal::AllocationAlignment) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 7: 0x104699e80 v8::internal::Factory::NewFillerObject(int, v8::internal::AllocationAlignment, v8::internal::AllocationType, v8::internal::AllocationOrigin) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 8: 0x104ab555c v8::internal::Runtime_AllocateInYoungGeneration(int, unsigned long*, v8::internal::Isolate*) [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
 9: 0x104f75e9c Builtins_WasmCEntry [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
10: 0x104f762e4 Builtins_StringAdd_CheckNone [/Users/cipolleschi/.nvm/versions/node/v22.15.0/bin/node]
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I prepared a reproducer for this problem in this PR in the React Native repo.

To test this out, you can simply:

git clone https://github.com/facebook/react-native
cd react-native
git checkout cipolleschi/integrate-bacons/xcode // this is not a fork
yarn
cd packages/rn-tester
node scripts/test-bacons-xcode.js

Let me know if I can help somehow!

Edit: I tried to debug the Writer a little and there is something weird happening.
The indent variable reaches a value of 417, which is clearly not correct!

[wodin]

#27 might be relevant

No idea about the 417 indent, though

[brentvatne]

@byCedric will investigate this

[byCedric]

In this library, we have two APIs.

1. The JSON-representation of the pbxproj (in https://github.com/EvanBacon/xcode/tree/main/src/json)
   • This handles parsing and serialization
2. The API-representation of the pbxproj
   • This includes a model-based representation of the json data.
   • It contains helpful methods to traverse, mutate, or extract specific data

Right now, to serialize back to the pbxproj format you'd have to use the JSON API directly. But, you can't provide the API representation. Once you do that, the JSON serialization can't figure out the proper structures and will cause to infinitely try to recurse and serialize objects (because the API has parent references, etc).

In essence:

import { XcodeProject } from '@bacons/xcode';
import { build } from '@bacons/xcode/json';

const PBXPROJ_PATH = 'path/to/proj.pbxproj';
const project = XcodeProject.open(PBXPROJ_PATH);

// ❌ Don't do this
const pbxproj = build(project);

// ✅ Do this
const pbxproj = build(project.toJSON());

[cipolleschi]

Thanks @byCedric for the explanation.
I think it would be nice to have a single entry point. If we read the Xcode project with XcodeProject.open(PBXPROJ_PATH);, it would be nice to have a project.write(PBXPROJ_PATH); method that takes care of calling toJSON and to write on disk.

Also, in this way, we don't have to use a deep import into the xcode/json folder which seems to be an implementation details.

WDYT?