@capacitor/filesystem leaks memory on Filesystem.writeFile

[nicolascotton]

Bug Report

Plugin(s)

@capacitor/filesystem version 7.0.0

Capacitor Version

Capacitor Doctor   

Latest Dependencies:

  @capacitor/cli: 7.0.1
  @capacitor/core: 7.0.1
  @capacitor/android: 7.0.1
  @capacitor/ios: 7.0.1

Installed Dependencies:

  @capacitor/ios: not installed
  @capacitor/core: 7.0.1
  @capacitor/android: 7.0.1
  @capacitor/cli: 7.0.1

[success] Android looking great! 👌

Platform(s)

Android for sure. I'm unable to test for iOS.

Current Behavior

When a file is written, the size of the file is leaked in memory.

Expected Behavior

There should be no memory leaks when writing a file.

Code Reproduction

I can provide the following code to reproduce the issue.

import { Component } from '@angular/core';
import { Directory, Encoding, Filesystem } from '@capacitor/filesystem';
import { IonButton } from '@ionic/angular/standalone';


@Component({
  selector: 'app-root',
  template: `<ion-button (click)="repro()">Repro</ion-button>`,
  standalone: true,
  imports: [IonButton],
})
export class AppComponent {
  async repro() {
    const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    const randomIndex = Math.floor(Math.random() * chars.length);
    const char = chars[randomIndex]; // Note that the leak only occurs when the data differs.
    const data = char.repeat(1024 * 1024 * 10); // 10mb of data
    return Filesystem.writeFile({
      directory: Directory.External,
      path: 'test.txt',
      encoding: Encoding.UTF8, // Does not happen with base64 encoding.
      data
    })
  }
}

Open the dev tools and click on the repro button.
Notice the memory is climbing up every time even if we run a GC.

Other Technical Details

I'm using Angular v18.
The leak only occurs when the data differs between writes & the encoding is not base64 (utf8).

Additional Context

None

[nicolascotton]

It's not a capacitor issue.
Removing the data from the options after writeFile solves the issue:

import { Component } from '@angular/core';
import { Directory, Encoding, Filesystem } from '@capacitor/filesystem';
import { IonButton } from '@ionic/angular/standalone';


@Component({
  selector: 'app-root',
  template: `<ion-button (click)="repro()">Repro</ion-button>`,
  standalone: true,
  imports: [IonButton],
})
export class AppComponent {
  repro() {
    const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    const randomIndex = Math.floor(Math.random() * chars.length);
    const char = chars[randomIndex]; // Note that the leak only occurs when the data differs.
    const data = char.repeat(1024 * 1024 * 10); // 10mb of data
    const options = {
      directory: Directory.External,
      path: 'test.txt',
      data,
      encoding: Encoding.UTF8
    };
    return Filesystem.writeFile(options)
      .finally(() => (options.data as any) = null);
  }
}