Electron cannot access user data directory when using Selenium ChromeDriver - selenium

Question

I am using Selenium with Robot Framework to run an Electron application. The application is built to read a configuration file from the user data directory. As far as I understand, this is the location where this file should be stored.
The electron main process reads the configuration file:
const localConfigFile = path.join(app.getPath('userData'), 'config.json');
const localConfig = fs.existsSync(localConfigFile) ? require(localConfigFile) : {};
The built production version works just fine and reads the file as expected, but when starting it from Robot using SeleniumLibrary, the file is not read. This leads me to believe it's a problem with Robot, Selenium or ChromeDriver.
Robot creates the webdriver using SeleniumLibrary:
Create Webdriver Remote desired_capabilities=${starting_parameters} command_executor=http://127.0.0.1:9515
Where starting parameters are simply:
{ "chromeOptions": {"binary": <binary_location> }}
Chromedriver is started as a separate process from /usr/bin/chromedriver where it has been installed and uses the default port 9515.
The versions that I am using are:
ChromeDriver 2.36.540471 (9c759b81a907e70363c6312294d30b6ccccc2752)
"electron": "^6.0.2"
"electron-builder": "^21.2.0"
robotframework==3.2.1
robotframework-seleniumlibrary==3.3.1
Ubuntu 18.04.4 LTS

Answer 1

Experienced the same problem. Finally changing the Chromedriver's user-data-dir argument to Electron's userDataDir solved the problem.
options.add_argument('--user-data-dir=' + str(app_config_path()))

Answer 2

I found out the problem by using Spectron and logging the Electron main console. In general I would advice using Spectron instead of Robot to test Electron apps.
The issue is that the user data directory was not the same as the Electron default. When running the application through Chromedriver, the user data directory is changed to /tmp/somethingsomething so naturally the file under ~/.config/app-name was not found.
My solution was to use Electron'ss application data directory instead:
app.getPath('appData')
By default this is one directory up from the user data directory, but remains the same when running through Chromedriver.