The "no matching distributions" hint is shown for packages that are installable

[2ykwang]

Description

Pip reports no matching distributions available for your environment for urllib3, but urllib3==2.7.0 installs fine on its own.

Expected behavior

That message only names packages that really have no candidates for the current environment.

pip version

26.1.2

Python version

3.14

OS

macOS

How to Reproduce

$ pip install --dry-run "botocore==1.29.0" "urllib3==2.7.0"

Output

$ pip install --dry-run "botocore==1.29.0" "urllib3==2.7.0"
...
The conflict is caused by:
    The user requested urllib3==2.7.0
    botocore 1.29.0 depends on urllib3<1.27 and >=1.25.4

Additionally, some packages in these conflicts have no matching distributions available for your environment:
    urllib3

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip to attempt to solve the dependency conflict

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts

$ pip index versions urllib3
urllib3 (2.7.0)
Available versions: 2.7.0, 2.6.3, 2.6.2, 2.6.1, 2.6.0, 2.5.0, ...

$ pip install --dry-run "urllib3==2.7.0"                                                                                poc/git/main
Collecting urllib3==2.7.0
  Using cached urllib3-2.7.0-py3-none-any.whl.metadata (6.9 kB)
Would install urllib3-2.7.0

Code of Conduct

• I agree to follow the PSF Code of Conduct.

[pfmoore]

Um, as the message says, botocore depends on urllib3<1.27, >=1.25.4. But you're requesting urllib3 2.7.0, which doesn't satisfy that constraint.

The message (and behaviour) seems perfectly fine to me...

[notatallshaw]

I'll take a look when I'm near a computer, the "Additionally," message looks off but I would need to reproduce to understand.

[2ykwang]

@pfmoore Sorry, the issue body wasn't clear enough.

This part is correct:

    The conflict is caused by:
        The user requested urllib3==2.7.0
        botocore 1.29.0 depends on urllib3<1.27 and >=1.25.4

What felt off is the one under it, which reads as if urllib3 can't be installed at all. that's what I opened the issue for:

    Additionally, some packages in these conflicts have no matching distributions available for your environment:
        urllib3

[2ykwang]

@notatallshaw From what I found, using find_all_candidates() in _has_any_candidates() makes the message go away. Since I wasn’t sure whether this is intentional, I opened an issue instead of a PR.

[notatallshaw]

Yeah, that's probably the correct fix.

[pfmoore]

What felt off is the one under it

Ah, right - good catch.