.dev suffix not correctly recognized as a prerelease in pdm

[tyong920]

Describe the bug

When using pdm, I noticed that versions with a .dev suffix (e.g., prefect 3.1.3.dev1) are not correctly identified as prerelease versions. From examining the code, it appears that the current logic only recognizes versions with {a|b|rc}N suffixes as prereleases. This means that .dev versions are mistakenly treated as stable releases, which can cause issues when managing dependencies.

To reproduce

1. Add a dependency with a .dev version, such as prefect 3.1.3.dev1
2. Attempt to constrain updates to stable releases only
3. Observe that .dev versions are not treated as prereleases.

Expected Behavior

Versions with a .dev suffix should be identified as prerelease versions, similar to versions with {a|b|rc}N suffixes, to ensure consistency and prevent unstable versions from being installed when only stable releases are desired.

Environment Information

PDM version:
2.20.1
Python Interpreter:
/home/projects/p-g/.venv/bin/python (3.12)
Project Root:
/home/projects/p-g
Local Packages:

{
"implementation_name": "cpython",
"implementation_version": "3.12.4",
"os_name": "posix",
"platform_machine": "x86_64",
"platform_release": "5.4.0-150-generic",
"platform_system": "Linux",
"platform_version": "#167~18.04.1-Ubuntu SMP Wed May 24 00:51:42 UTC 2023",
"python_full_version": "3.12.4",
"platform_python_implementation": "CPython",
"python_version": "3.12",
"sys_platform": "linux"
}

pdm -v output

No response

Additional Context

No response

Are you willing to submit a PR to fix this bug?

• Yes, I would like to submit a PR.

[tyong920]

https://peps.python.org/pep-0440/#appendix-b-parsing-version-strings-with-regular-expressions

[frostming]

• Add a dependency with a .dev version, such as prefect 3.1.3.dev1
• Attempt to constrain updates to stable releases only
• Observe that .dev versions are not treated as prereleases.

I don't understand these steps, can you make it clear with commands? How did you add the dependency and how did you constrain updates to stable releases only? @tyong920

Basically if a prerelease has been locked in the lock file, following updates will respect and allow prereleases.

[tyong920]

@frostming Thank you very much for your prompt response and insightful feedback!

Bingo! Your note, “Basically, if a prerelease has been locked in the lock file, following updates will respect and allow prereleases”, was exactly on point. Following this advice led me to identify the actual root cause: a transitive dependency in our project directly specifies dependencies = ["prefect>=3.0.0rc1"], which permits prerelease versions and is the underlying reason for the unexpected .dev version installations.

Thanks again for your valuable input, which helped clarify this situation!