log which python version to use/was used

[graingert]

eg add this to the header:

 # This file is autogenerated by pip-compile on:
 # Python 2.7.15+ (default, Oct  2 2018, 22:12:08) 
 # [GCC 8.2.0] on linux2
 # To update, run:
 #
 #    pip-compile --generate-hashes --output-file=requirements.txt requirements.in

[riordan]

Would be great to also log the pip version used. Some packages have minimum pip versions (as I'm finding out now), so if you run your pip-compile in an environment with a different pip version from the one you're installing into (e.g. fresh and new and 19.x on your local laptop, but stuck at 9.x on ubuntu in the docker container), it's possible to get installation incompatibility errors.

This'll help users identify that could be an environment difference causing issues.

[graingert]

@riordan the pip version is already logged if packages eronously depend on pip

Also you can use pip install --no-deps --require-hashes -r requirements.txt to avoid pip dependency resolution getting in the way

[atugushev]

@riordan

Some packages have minimum pip versions (as I'm finding out now), so if you run your pip-compile in an environment with a different pip version from the one you're installing into (e.g. fresh and new and 19.x on your local laptop, but stuck at 9.x on ubuntu in the docker container), it's possible to get installation incompatibility errors.

Hello @riordan! You could use --allow-unsafe option, which allows you to pin pip in requirements.txt (by default it's commented-out as an unsafe package).

[atugushev]

@graingert

Also you can use pip install --no-deps --require-hashes -r requirements.txt to avoid pip dependency resolution getting in the way

Yeah, that should also work. Shouldn't we have --no-deps and --require-hashes in pip-sync as well?

[graingert]

`--require-hashes` is only useful when passed as a cli directly to the pip invocation

…

On Fri, 15 Nov 2019, 02:53 Albert Tugushev, ***@***.***> wrote: @graingert <https://github.com/graingert> Also you can use pip install --no-deps --require-hashes -r requirements.txt to avoid pip dependency resolution getting in the way Yeah, that should also work. Shouldn't we have --no-deps and --require-hashes in pip-sync as well? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#827?email_source=notifications&email_token=AADFATG7ENQ2RQHKW4LDK5DQTYFLFA5CNFSM4HQBART2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEEEDVYA#issuecomment-554187488>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADFATCN2Y4UCGKEBZPJIXTQTYFLFANCNFSM4HQBARTQ> .

[atugushev]

--require-hashes is only useful when passed as a cli directly to the pip invocation

pip-sync invokes pip install /tmp/file/with/requirements.txt under the hood.

[AndydeCleyre]

FWIW, zsh wrapper to accomplish this:

pip-compile-withpyver () {
    CUSTOM_COMPILE_COMMAND=$(
        print -l \
            "pip-compile ${(j: :)@}" \
            '#' \
            "# Last compiled with: ${(j: :)${(f)$(python -V)}}"
    ) pip-compile $@
}

$ pip-compile-withpyver --generate-hashes requirements.in

#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile --generate-hashes requirements.in
#
# Last compiled with: Python 3.6.9 (1608da62bfc71e8ac775121dd0b21bb72e61c6ea, Dec 25 2019, 02:47:23) [PyPy 7.3.0 with GCC 9.2.0]
#
...