Even though the CIDR range is in NO_PROXY, HTTP_PROXY still takes effect

[softyoungha]

I discovered an issue while using httpx in Airflow.
Contrary to what is documented in httpx

httpx/httpx/_utils.py

Lines 228 to 239 in db9072f

	# NO_PROXY can include domains, IPv6, IPv4 addresses and "localhost"
	# NO_PROXY=example.com,::1,localhost,192.168.0.0/16
	if "://" in hostname:
	mounts[hostname] = None
	elif is_ipv4_hostname(hostname):
	mounts[f"all://{hostname}"] = None
	elif is_ipv6_hostname(hostname):
	mounts[f"all://[{hostname}]"] = None
	elif hostname.lower() == "localhost":
	mounts[f"all://{hostname}"] = None
	else:
	mounts[f"all://*{hostname}"] = None

,
when I inputs a CIDR range in no_proxy, I found that the proxy settings were still being used, even for addresses within that range

you can try this

import os
from httpx._utils import get_environment_proxies

os.environ["http_proxy"] = "http://proxy.example.com"
os.environ["https_proxy"] = "http://proxy.example.com"
os.environ["no_proxy"] = "localhost,10.0.0.0/8"

httpx_proxy_info = get_environment_proxies()
print(httpx_proxy_info)
# {
#       'http://': 'http://proxy.example.com',
#       'https://': 'http://proxy.example.com',
#       'all://localhost': None,
#       'all://10.0.0.0/8': None     <- no_proxy
# }

from httpx._utils import URLPattern
from httpx._urls import URL

url_pattern = URLPattern("all://10.0.0.0/8")
print(url_pattern.matches(URL("http://10.0.0.0")))
# True
print(url_pattern.matches(URL("http://10.240.5.168")))
# False

After reviewing the code, it seems that it can only interpret bit ranges like /8, /16, /24 as URL delimiter slashes due to its structure.
I tried to make custom modifications, but it looks like significant changes would be needed within mounts as well, so I gave up

This issue is quite important to me, so I've also raised it in Airflow.

apache/airflow#39794

I'm curious if there are any other methods or plans to fix it.