install options have no effect?

[haampie]

I have the impression that none of this:

python-zstandard/setup.py

Lines 56 to 82 in 80c3142

	# PyPy doesn't support the C backend.
	if platform.python_implementation() == "PyPy":
	C_BACKEND = False
	if "--legacy" in sys.argv:
	SUPPORT_LEGACY = True
	sys.argv.remove("--legacy")
	if "--system-zstd" in sys.argv:
	SYSTEM_ZSTD = True
	sys.argv.remove("--system-zstd")
	if "--warnings-as-errors" in sys.argv:
	WARNINGS_AS_ERRORS = True
	sys.argv.remove("--warning-as-errors")
	if "--no-c-backend" in sys.argv:
	C_BACKEND = False
	sys.argv.remove("--no-c-backend")
	if "--no-cffi-backend" in sys.argv:
	CFFI_BACKEND = False
	sys.argv.remove("--no-cffi-backend")
	if "--rust-backend" in sys.argv:
	RUST_BACKEND = True
	sys.argv.remove("--rust-backend")

actually does anything.

I can pass --install-option=--no-c-backend but it is ignored.

[DjDeepDive]

Furthermore, checking for sys.argv directly is brittle, as PIP is deprecating the ability to pass arguments this way at all. This should all be changed to --config-settings KEY=VALUE format if possible:

DEPRECATION: --build-option and --global-option are deprecated. pip 23.3 will enforce this behaviour change. A possible replacement is to use --config-settings. Discussion can be found at https://github.com/pypa/pip/issues/11859