`pip list --quiet` squelches normal output

[aukalas]

Environment

• pip version: 20.1.1
• Python version: Python 2.7/3.8
• OS: Arch Linux

Description
When running pip list --quiet or pip list --quiet --quiet, normal output is suppressed, not just warnings. This differs from the behavior of pip freeze (which I am switching from as advised in #8174 (comment)).

Expected behavior
Package listing is output, but no warnings.

Actual behavior
With --quiet, only warnings are output. With --quiet --quiet, nothing is output.

How to Reproduce

• Run in Python 2 so that you get the deprecation notice. (This is not necessary, but illustrates better what's happening.)
• Have a few packages installed.

See below for commands to try.

Output

$ pip2 list --format=freeze
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
appdirs==1.4.4
[…]
$ pip2 list --format=freeze --quiet
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
$ pip2 list --format=freeze --quiet --quiet

For comparison:

$ pip2 freeze                       
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
appdirs==1.4.4
[…]
$ pip2 freeze --quiet
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
-f https://leifarne%40auka.io:8YxwbRIe4MAlV5XtXBGVVRY68DWb4S2Rc4x1qNeO6vA@auka-build-tools.appspot.com/find-links
appdirs==1.4.4
[…]
$ pip2 freeze --quiet --quiet
appdirs==1.4.4
[…]

[deveshks]

So we decide the verbosity of a command here:

pip/src/pip/_internal/cli/base_command.py

Line 137 in 2f9b50c

self.verbosity = options.verbose - options.quiet

and then the following function defined the log level based on verbosity value

pip/src/pip/_internal/utils/logging.py

Lines 278 to 294 in 2f9b50c

	def setup_logging(verbosity, no_color, user_log_file):
	"""Configures and sets up all of the logging
	Returns the requested logging level, as its integer value.
	"""
	# Determine the level to be logging at.
	if verbosity >= 1:
	level = "DEBUG"
	elif verbosity == -1:
	level = "WARNING"
	elif verbosity == -2:
	level = "ERROR"
	elif verbosity <= -3:
	level = "CRITICAL"
	else:
	level = "INFO"

When we pass -qq to pip list --format=freeze, we have self.verbosity == -2, making log level as ERROR, and none of the write_output functions below are called, which are at log level INFO

pip/src/pip/_internal/commands/list.py

Lines 240 to 246 in 2f9b50c

	elif options.list_format == 'freeze':
	for dist in packages:
	if options.verbose >= 1:
	write_output("%s==%s (%s)", dist.project_name,
	dist.version, dist.location)
	else:
	write_output("%s==%s", dist.project_name, dist.version)

[aukalas]

Thanks @deveshks! 🙌 Should list also be using sys.stdout.write, like freeze? Seems appropriate, since the package list is the desired output of the command (it's not exactly logging).

[bartoli]

I also 'vote' for sys.stdout.write. I think just removing the if around the write_output calls would still pass the outut as the wrong level?
I can do the PR if accepted