Comment in requirements file cause failed check

[janusheide]

Checking a requirements file with a comment (e.g. #comment) causes the following error:

not enough values to unpack (expected 1, got 0)

Comments should be allowed according to this:
https://pip.pypa.io/en/latest/reference/pip_install/#requirements-file-format

And it looks like the official example files also currently fails
https://pip.pypa.io/en/latest/reference/pip_install/#example-requirements-file

[cjwelborn]

You are totally correct. I haven't been working on my projects lately. I see that some of them are starting to show their age. I'll see what I can do this week to rectify some of that. Also, I always accept pull requests that don't break backward compatibility. Thank you for the report.

[janusheide]

Thanks! Will keep that in mind.

[cjwelborn]

I managed to look into this today, and it seems the problem is in requirements-parser itself (not mine). If i have time I will see what I can do to fix it. This is the actual traceback:

Traceback (most recent call last):                                                                                                                                          
  File "/home/cj/scripts/requirementz/requirementz/__main__.py", line 275, in entry_point                                                                                   
    mainret = main(docopt(USAGESTR, version=VERSIONSTR, script=SCRIPT))                                                                                                     
  File "/home/cj/scripts/requirementz/requirementz/__main__.py", line 175, in main                                                                                          
    location=argd['--location'],                                                                                                                                            
  File "/home/cj/scripts/requirementz/requirementz/__main__.py", line 225, in check_requirements                                                                            
    reqs = Requirementz.from_file(filename=filename)                                                                                                                        
  File "/home/cj/scripts/requirementz/requirementz/tools.py", line 543, in from_file                                                                                        
    reqs = cls.from_lines(f.readlines())                                                                                                                                    
  File "/home/cj/scripts/requirementz/requirementz/tools.py", line 553, in from_lines                                                                                       
    for l in sorted(lines) if l.strip()                                                                                                                                     
  File "/home/cj/scripts/requirementz/requirementz/tools.py", line 482, in __init__                                                                                         
    super(Requirementz, self).__init__(requirements or tuple())                                                                                                             
  File "/usr/lib/python3.6/collections/__init__.py", line 1039, in __init__                                                                                                 
    self.data = list(initlist)                                                                                                                                              
  File "/home/cj/scripts/requirementz/requirementz/tools.py", line 553, in <genexpr>                                                                                        
    for l in sorted(lines) if l.strip()                                                                                                                                     
  File "/home/cj/.local/lib/python3.6/site-packages/requirements/requirement.py", line 220, in parse                                                                        
    return cls.parse_line(line)                                                                                                                                             
  File "/home/cj/.local/lib/python3.6/site-packages/requirements/requirement.py", line 198, in parse_line                                                                   
    pkg_req = Req.parse(line)                                                                                                                                               
  File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 3155, in parse                                                                              
    req, = parse_requirements(s)                                                                                                                                            
ValueError: not enough values to unpack (expected 1, got 0)

I'm depending on requirements-parser to do the actual parsing, so I may end up having to drop that dependency.

[janusheide]

Thanks for having a look, yes it does appear that requirements-parser have a problem and its not likely that it will get updated, but you can of course ask the maintainer :)

I also regularly use a tool called "pur" https://pypi.org/project/pur/ but it seems they implemented their own parser
https://github.com/alanhamlett/pip-update-requirements/blob/master/pur/packages/pip/_internal/cli/parser.py

You could also consider creating a new file object in memory and just strip all comment lines, not exactly elegant approach but easy and should fix the problem for now. But personally I dont like to depend on unmaintained projects, its just pushing some unavoidable work ahead of you.

I also had a quick look in pip
https://github.com/pypa/pip/blob/7ec0fa5142466f8402bb866a1dcfb8ca6ffdc66b/src/pip/_vendor/pkg_resources/__init__.py#L3075
kinda a funny, they also just drop comment lines... ane then processed to make a call that their documentation says they should not make, and its in all caps.