Cannot switch context to Chrome Custom Tab

The problem

We are unable to switch Context to the Chrome Custom Tab context.

Environment

• Appium version (or git revision) that exhibits the issue: 1.15.1
• Last Appium version that did not exhibit the issue (if applicable): -
• Desktop OS/version used to run Appium: macOS Catalina
• Node.js version (unless using Appium.app|exe):
• Npm or Yarn package manager:
• Mobile platform/version under test: Android 9
• Real device or emulator/simulator: Real
• Appium CLI or Appium.app|exe: Appium.app

Details

When our Chrome Custom Tab is displayed, we cannot switch context to it. This means we are unable to automate our login page. We get the following error message:

>>> driver.switch_to.context(driver.contexts[1])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/appium/webdriver/switch_to.py", line 30, in context
    self._driver.execute(MobileCommand.SWITCH_TO_CONTEXT, {'name': context_name})
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/selenium/webdriver/remote/webdriver.py", line 321, in execute
    self.error_handler.check_response(response)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/appium/webdriver/errorhandler.py", line 29, in check_response
    raise wde
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/appium/webdriver/errorhandler.py", line 24, in check_response
    super(MobileErrorHandler, self).check_response(response)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: An unknown server-side error occurred while processing the command. Original error: An unknown server-side error occurred while processing the command. Original error: unknown error: Failed to get sockets matching: @webview_devtools_remote_.*16060
  (make sure the app has its WebView configured for debugging)

Link to Appium logs

https://gist.github.com/roddymunro/1778d2a0c98d1eddb5b0d52225d64dd8

[KazuCocoa]

As https://github.com/appium/appium/issues/13543#issuecomment-846686776 , basic custom tabs work at least 1.21.0.

[KazuCocoa]

I tested the custom tab with https://github.com/GoogleChrome/android-browser-helper/tree/main/demos/custom-tabs-example-app . Then, it worked like the below. (Emulator and developers option enabled to debug chrome browser). So, it seems to work for now. (At least, I tested the repository with Appium 1.21.0 and current master) (Possibly older version may require chromeOptions and androidPackage to handle chrome package name)

https://gist.github.com/KazuCocoa/708fc5f297e5d60cf9862f930ddcabd2

[5] pry(#<AppiumLibCoreTest::DriverTest>)> @driver = @@core.start_driver
=> #<Appium::Core::Base::Driver:0xc7f7de9e752e902 browser="unknown">
[6] pry(#<AppiumLibCoreTest::DriverTest>)> @driver.available_contexts
=> ["NATIVE_APP", "WEBVIEW_chrome"]
[7] pry(#<AppiumLibCoreTest::DriverTest>)> @driver.context = 'WEBVIEW_chrome'
=> "WEBVIEW_chrome"
[8] pry(#<AppiumLibCoreTest::DriverTest>)> @driver.title
=> "Android Developers"

According to https://developer.chrome.com/docs/android/custom-tabs/integration-guide/ , the chrome package name can be different in beta and stable. Then, probably it requires to set "chromeOptions": { "androidPackage": "com.android.beta" } for example.

appium:enableWebviewDetailsCollection: true may also need. (This was not needed on my environment though)

---

What’s the result of https://github.com/appium/appium-uiautomator2-driver#mobile-getcontexts in your case? It may print all available chrome tabs on the device via chrome://inspect/#devices. It should help to investigate your case.