Debug mode

[blueyed]

When debugging issues pip-tools should be more helpful:

1. print/log executed commands, e.g. https:/pypa/pip/blob/f8732ac06dcb7c6af81dcdc0cc3158196b796baf/src/pip/_internal/utils/misc.py#L721 - pip appears to have some logging for this (see the --log option), which could be configured for this
2. keep build directories, so that you can run the setup commands from there. Currently pip cleans them up.

This could be triggered through PIPTOOLS_DEBUG in the environment, -vv, or a new --debug option.

It might be worth/good to have this with pip itself via an environment already, i.e. PIP_DEBUG=1 would behave like using --log=/dev/stderr.

pip's logging get setup here: https:/pypa/pip/blob/f8732ac06dcb7c6af81dcdc0cc3158196b796baf/src/pip/_internal/cli/base_command.py#L133-L137

[atugushev]

Hello @blueyed,

Sounds reasonable!

2. keep build directories, so that you can run the setup commands from there. Currently pip cleans them up.

Do you know how to force pip to keep build directories?

[atugushev]

Related to #321

[atugushev]

• print/log executed commands, e.g. https:/pypa/pip/blob/f8732ac06dcb7c6af81dcdc0cc3158196b796baf/src/pip/_internal/utils/misc.py#L721 - pip appears to have some logging for this (see the --log option), which could be configured for this
• keep build directories, so that you can run the setup commands from there. Currently pip cleans them up.

#1080 introduced --pip-args, so now any additional pip's options can be passed, e.g.:

$ pip-compile --pip-args="--no-clean -vv"

I'll close this then. Feel free to reopen if it doesn't resolve the issue. Thanks!