Incorrect documentation on requirements.txt format

While attempting to fix an issue in pip-tools, it was discovered that the documentation for the requirements.txt format conflicts with the actual behaviour of pip when it parses a requirements.txt file.

The documentation for requirements.txt format mentions Comments are stripped before line continuations are processed. but the pip code appears to do the opposite, processing the line continuations before it strips the comments.

Which one is correct?

[atugushev]

I made an experiment (#8094) and swapped the lines to see what happens. Two tests test_comments_and_joins_case1 and test_comments_and_joins_case3 are failed, see the tests:

https://github.com/pypa/pip/blob/a531a15376ae8ee9670c1ab15262876a96624b97/tests/unit/test_req_file.py#L76-L100

Since this case:

package1 \
   # a comment
package2

is pretty legit and well tested, thus we may assume that there is a bug in documentation rather than in code.

[AndydeCleyre]

Just in case it’s missed, all that’s needed IMO is #7780.