fix user conflicts with version ranges

[memsharded]

Changelog: Bugfix: Solve conflict not raised when version-ranges have different user.
Docs: Omit

Close #17875

[memsharded]

CI failure is unrelated, will be fixed once develop2 is fixed

[kiloalphaindia]

We used this to provide our own packages. By providing pkg/2.1@me/stable to satisfy pkg/[>=2] in dependent packages with our own patched versions.
How is the recommended way to provide your own patched packages without fully ignoring version requirements in other packages?

[memsharded]

Hi @kiloalphaindia

We used this to provide our own packages. By providing pkg/2.1@me/stable to satisfy pkg/[>=2] in dependent packages with our own patched versions.

I am afraid this was never an intended use case, pkg/[version_range] doesn't resolve to pkg/version@user/channel in the general case, the fix in this PR was about conflicts not being detected.

How is the recommended way to provide your own patched packages without fully ignoring version requirements in other packages?

Not sure what is exactly the question. In general the idea is that user/channel are immutable parts of the package reference, they cannot be used as variables or replaced.
If you want to do full downstream requirement replacing, you might use the [replace_requires] feature, but this is intended more for other use cases and problem solving, not as a resolution mechanism.
The recommended approach in general would be to align and make all pkg packages have the same referencing, all of them using user/channel or none of them using user/channel, but not mixing both approaches.

If we are talking about ConanCenter packages, there are guidelines in https://docs.conan.io/2/devops/conancenter/hosting_binaries.html

Do not add user/channel to these packages, it is way simpler to use them as zlib/1.2.13 without user-channel. The user/channel part would be mostly recommended for your own proprietary packages, but not for open source ConanCenter packages.

If you have further questions, it might be better to create a new ticket, to track it.