New readthedocs project solves pdf build Problem

[SimeonEhrig]

Since we moved to the configuration file format v2, the pdf build of our readthedocs page failed.

Error

Build output directory for format "pdf" contains multiple files and it is not currently supported. Please, remove all the files but the "pdf" you want to upload.

We didn't recognized immediately because the preview in PRs was still working (does not build pdf) and we didn't configured an e-mail notification. Simple fixes does not solve the problem. Therefore I created a second readthedocs page, which uses my fork for testing purpose. The build of the fork works without problem. It used the same development branch like the upstream.

I found only one difference between both readthedocs project. The upstream runs the following command:

python -m pip install --upgrade --no-cache-dir pillow mock==1.0.1 alabaster>=0.7,<0.8,!=0.7.5 commonmark==0.9.1 recommonmark==0.5.0 sphinx sphinx-rtd-theme readthedocs-sphinx-ext<2.3

and the fork this command:

python -m pip install --upgrade --no-cache-dir sphinx readthedocs-sphinx-ext 

In the documentation, there is mentioned, that it happens because it the upstream is "legacy" project: https://docs.readthedocs.io/en/stable/build-default-versions.html#python

I'm not sure, if this causes the problem and if yes, how to move the readthedocs project to a "non-legacy" state.

Details

• Read the Docs project URL: https://readthedocs.org/projects/alpaka/
• Build URL (if applicable): https://readthedocs.org/projects/alpaka/builds/21693635/
• Read the Docs project of the fork URL: https://readthedocs.org/projects/alpaka-test/
• Build URL of the fork (if applicable): https://readthedocs.org/projects/alpaka-test/builds/21693936/
• Read the Docs username (if applicable): https://readthedocs.org/profiles/SimeonEhrig/

[humitos]

New projects are installing only sphinx and readthedocs-sphinx-ext. We announced this at https://blog.readthedocs.com/python-core-requirements-changed/

I added the project alpaka to the feature flag so it has that new behavior and triggered a new build for its latest version at https://readthedocs.org/projects/alpaka/builds/21709321/. Let me know if it works as you expects.

We plan to migrate all projects to the new behavior in the following months.

[SimeonEhrig]

@humitos Thanks for your help. I see that the dependencies are not installed anymore. Therefore the change was successful. Unfortunately, it does not solve the problem :-(

[humitos]

@SimeonEhrig how many PDF files are generated when you run the PDF command locally? Make sure that only 1 is generated, since Read the Docs does not support more than 1 currently (see #2045)

[SimeonEhrig]

@humitos Indeed, this was the problem. We stored the project logo in a pdf for the latex documentation. I replaced it by a png and now it is working. Thank you very much. But it is little bit strange, that my fork builds. Nevertheless the problem is solved.

P.S.: I already found the PR, which will solve the problem in future: #10438