[iOS] Sending form data via fetch or axios leaks memory

Description

Sending files via form data with fetch or axios allocates memory 2-3 times the size of the file. The memory is not freed even after getting a response.

This is how memory usage spikes and stays the same until you kill the app.

When uploading a 15.8MB file, the usage spikes by 42MB and only gets reduced by 5MB after upload finishes. When uploading a 47.9MB file, the usage spikes by 115MB and gets reduced by 15MB after upload finishes.

This leads to crashes after uploading a few decently sized files.

Version

0.68.2

Output of npx react-native info

info Fetching system and libraries information… System: OS: macOS 12.3 CPU: (8) arm64 Apple M1 Memory: 99.58 MB / 16.00 GB Shell: 5.8.1 - /opt/homebrew/bin/zsh Binaries: Node: 18.0.0 - /opt/homebrew/bin/node Yarn: 1.22.18 - ~/.nvm/versions/node/v16.14.2/bin/yarn npm: 8.6.0 - /opt/homebrew/bin/npm Watchman: 2022.03.21.00 - /opt/homebrew/bin/watchman Managers: CocoaPods: 1.11.3 - /usr/local/bin/pod SDKs: iOS SDK: Platforms: DriverKit 21.4, iOS 15.4, macOS 12.3, tvOS 15.4, watchOS 8.5 Android SDK: Not Found IDEs: Android Studio: 2021.2 AI-212.5712.43.2112.8609683 Xcode: 13.3.1/13E500a - /usr/bin/xcodebuild Languages: Java: 11.0.15 - /usr/bin/javac npmPackages: @react-native-community/cli: Not Found react: 17.0.2 => 17.0.2 react-native: 0.68.2 => 0.68.2 react-native-macos: Not Found npmGlobalPackages: react-native: Not Found

Steps to reproduce

1. Create a form data object with a file attached to it
2. POST it via fetch or axios
3. Observe the app’s memory usage

Snack, code example, screenshot, or link to a repository

I have prepared a small demo project where you can upload 2 files of different sizes via fetch or axios to easily reproduce the issue. https://github.com/dklymenk/rn-formdata-memory-leaks

[MichaelBorde]

I have run your rn-formdata-memory-leaks project.

I have used a standalone debug apk with hermes enabled to get a very stable memory usage.

I do notice some memory increase corresponding to file size (15 MB or 50 MB) during total upload process. I suspect this is due to the download of the file because you are creating a form data based on url. Using my application, I upload a local file and I don’t notice such memory increase.

Besides, after something like 20 attempts, I can see something like 30 MB of memory increase. PSS usage was 91 MB at start then after my tests, usage was 122 MB. I don’t know if such memory will be released later (30 MB is not much).

[github-actions[bot]]

This issue was closed because it has been stalled for 7 days with no activity.