Validate conf.py before build docs

[humitos]

This build https://readthedocs.org/projects/wagtail/builds/7918857/ produced a log into Sentry as an ERROR https://sentry.io/read-the-docs/readthedocs-org/issues/712546002/?query=is:unresolved which is annoying. These exceptions are raised to communicate a specific message to the user and shouldn't be logged as ERROR for us to take a look at.

I'm not sure if this is already implemented in v2 of our configuration or not.

There is some related work at #4495 and #4590.

[stsewd]

I think this happens when we try to find aconf.py file for the user and we found more than one. With v2 we still keep the find automatically magic.

[ba11b0y]

@stsewd So is this supposed to be fixed? If yes, I would like to take a stab at it.

[stsewd]

@invinciblycool we can't validate this on the config module because we put None when rtd needs to find the file automatically, I think there is a case where rtd fails to find one or there are multiple config files, we need to dig a little more to see the entire flow and see how we want to fix this.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stsewd]

We haven't seen this in ~2 months, we should test if this can be replicated. I think it was raised when the project has 2 conf.py files, and isn't using a config file.

[stsewd]

I was able to replicate this locally

Traceback (most recent call last):
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/doc_builder/backends/sphinx.py", line 176, in append_conf
    self.config_file or self.project.conf_file(self.version.slug)
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/projects/models.py", line 719, in conf_file
    ProjectConfigurationError.MULTIPLE_CONF_FILES,
readthedocs.projects.exceptions.ProjectConfigurationError: We found more than one conf.py and are not sure which one to use. Please, specify the correct file under the Advanced settings tab
 in the project's Admin.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/projects/tasks.py", line 565, in run_build
    outcomes = self.build_docs()
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/projects/tasks.py", line 830, in build_docs
    outcomes['html'] = self.build_docs_html()
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/projects/tasks.py", line 847, in build_docs_html
    html_builder.append_conf()
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/doc_builder/backends/sphinx.py", line 183, in append_conf
    ).with_traceback(trace)
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/doc_builder/backends/sphinx.py", line 176, in append_conf
    self.config_file or self.project.conf_file(self.version.slug)
  File "/home/stsewd/rtd/readthedocs.org/readthedocs/projects/models.py", line 719, in conf_file
    ProjectConfigurationError.MULTIPLE_CONF_FILES,
readthedocs.projects.exceptions.ProjectConfigurationError: A configuration file was not found. Make sure you have a conf.py file in your repository.

with this structure

├── conf.py
├── more
│   └── conf.py
├── README.rst
└── requirements.txt

[dojutsu-user]

@stsewd
Is this still valid?

[stsewd]

Yeah, I think we fail with a general exception with the above structure #4745 (comment)

[dojutsu-user]

@stsewd
I am not sure as what needs to be done here.
Can you provide some details here.