pip-sync errors when merging multiple requirements.txt files that point at the same editable install

[vivster7]

pip-sync raises an AttributeError: 'NoneType' object has no attribute 'specifier' error when you try and run it with multiple requirements files that each include an editable install for the same package.

Environment Versions

1. OS Type: Linux
2. Python version: Python 3.9.11
3. pip version: pip 22.3
4. pip-tools version: pip-compile, version 6.9.0

Steps to replicate

1. Create a setup.py, dev_requirements.in, requirements.in file

# setup.py
from setuptools import find_packages, setup
setup(name="a", version="0.0.1", packages=find_packages())

# dev_requirements.in
-e file:.

# requirements.in
-e file:.

2. Run pip-compile

pip-compile requirements.in
pip-compile dev_requirements.in

3. Run pip-sync

pip-sync requirements.in  dev_requirements.in

Expected result

I expected the editable package to install once. Similar to running pip install -r requirements.txt -r dev_requirements.txt

Actual result

pip-sync raised an error
Full stack trace

➜  scratch pip-sync  requirements.txt dev_requirements.txt 
Traceback (most recent call last):
  File "/home/vivek/.pyenv/versions/3.9.11/bin/pip-sync", line 8, in <module>
    sys.exit(cli())
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/piptools/scripts/sync.py", line 146, in cli
    merged_requirements = sync.merge(requirements, ignore_conflicts=force)
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/piptools/sync.py", line 115, in merge
    if ireq.specifier != existing_ireq.specifier:
  File "/home/vivek/.pyenv/versions/3.9.11/lib/python3.9/site-packages/pip/_internal/req/req_install.py", line 245, in specifier
    return self.req.specifier
AttributeError: 'NoneType' object has no attribute 'specifier'

...

[atugushev]

Alas, can't reproduce the bug. Could you show the pip --version output? This does look like you're using some old pip version.

[vivster7]

➜  /src git:(main) pip --version
pip 22.3 from /home/vivek/.pyenv/versions/3.9.11/envs/chrono/lib/python3.9/site-packages/pip (python 3.9)

Would it help if I pushed a Docker image with the repro in it?

[richafrank]

I was able to reproduce this, with the above versions, as well as on MacOS with Python 3.8.12 | pip 22.3.1 | pip-tools main, as well as Python 3.10.6.

@atugushev would be good to see if the tests I add fail for you too without the fix.

[richafrank]

(Added tests and fix in PR)