Seeing %MatchError{term: {:error, :obscured}} when calling execute_script with certain kinds of JavaScript

[mhanberg]

Issue

Elixir: 1.6.4
Erlang: 20.2.2
Google Chrome: Version 67.0.3396.99 (Official Build) (64-bit)
ChromeDriver: 2.36.540469 (1881fd7f8641508feb5166b7cae561d87723cfa8)

When attempting to use await with the execute_script function, I have experienced a %MatchError{term: {:error, :obscured}}.

session
|> visit(url)
|> execute_script("""
const resp = await fetch("#{url}").then(r => r.text());
return resp;
""")
|> page_source

This line of code works in the dev console on Chrome.

I have been told that %MatchError but might the incorrect error for this case.

---

I was able to work my way around this without needing to use await.

[keathley]

I think the issue is here: https://github.com/keathley/wallaby/blob/master/lib/wallaby/httpclient.ex#L70.

This was called out in an earlier issue but now I'm not sure what that issue was or why this wasn't fixed before. We should remove that status check and find a better way to surface errors. Returning the actual error text from the http response would be a good start and help illuminate whats really going on.

[keathley]

@mhanberg Do you have a minimal test case we can use to re-produce this locally?

[mhanberg]

@keathley The test case can be found here: https://github.com/mhanberg/wallaby_bug_demo.

[keathley]

@mhanberg Does this fail pretty reliably for you? I'm not seeing any errors. I just checked and it seems I'm running chromedriver 2.4 (same chrome version as you). Can you confirm that this error is present after updating to the latest chromedriver?

[mhanberg]

@keathley I upgraded to chromedriver 2.41 and the error persists.

Also, to clarify, the test case I provided may have been misleading, as it asserted that the MatchError would be raised, so a passing test indicates the problem is there. Sorry about that.

I have updated the test to fail when a MatchError is thrown.

[keathley]

Oh! Thats my fault. Should have looked closer at the test itself. Thats what I get for trying to rush around. Thanks for the clarity 👍.

[mhanberg]

It looks like the message that comes with this error is

Interactive Elixir (1.6.4) - press Ctrl+C to exit (type h() ENTER for help)
pry(1)> response
%{
  "sessionId" => "d701c566b82095684715f9eddc8adcbb",
  "status" => 13,
  "value" => %{
    "message" => "unknown error: Runtime.evaluate threw exception: SyntaxError: await is only valid in async function\n  (Session info: headless chrome=69.0.3497.100)\n  (Driver info: chromedriver=2.41.578706 (5f725d1b4f0a4acbf5259df887244095596231db),platform=Mac OS X 10.14.0 x86_64)"
  }
}

Which makes sense to me after reading PR #374

@keathley I have gone ahead and made a PR #389 to keep the error message instead of :obscure. Let me know what you think.

[keathley]

Thanks @mhanberg I'll take a look 👍

[mhanberg]

Fixed in #389