Fix series sorting for numeric, non-numeric, and range positions

[Harshul23]

Closes #12153

fix

Technical

This PR updates series sorting in openlibrary/core/lists/model.py to handle mixed position formats more predictably.

Previously, the sorting logic reduced position to a single float, which worked for simple numeric values but did not handle range-based entries like 1-3, 22-23, and 24-25 well.

This change replaces the float-based sort key with a tuple-based sort key so series items are ordered as:

• numeric positions first
• non-numeric positions next
• range-based positions last

For range-based positions, sorting is further stabilized by:

• range size (max - min)
• lower bound
• work key as a deterministic tie-breaker

Testing

Verified with:

pytest openlibrary/tests/core/lists/test_model.py

Result:

• TestList : test_owner passed
• TestSeries : test_series_sorting passed

Manual verification:

• checked the affected series ordering behavior locally
• confirmed single-number entries appear first
• confirmed non-numeric entries are handled safely
• confirmed range-based entries are sorted consistently and deterministically
• confirmed Refresh stability test

Screenshot

Sorting behavior was manually verified locally on the affected series page after the fix.

Screen.Recording.2026-03-25.at.1.40.39.AM.mov

Stakeholders

@cdrini @mekarpeles

[Copilot]

Pull request overview

Updates series seed ordering in the Lists/Series model so that mixed position formats (numeric, non-numeric, and ranges) sort in a more predictable, deterministic way, addressing incorrect ordering on series pages (e.g., 3-4 appearing before 1-2).

Changes:

• Replaces float-based series position sorting with a tuple-based sort key that buckets numeric, non-numeric, and range positions.
• Adds range parsing via regex and additional tie-breakers for deterministic ordering.
• Adds/extends unit test coverage for series sorting across numeric, non-numeric, range, and None positions.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
openlibrary/core/lists/model.py	Reworks Series.get_seeds() sorting logic to handle numeric/non-numeric/range positions deterministically.
openlibrary/tests/core/lists/test_model.py	Adds a focused test validating the intended ordering across mixed position formats.

[cdrini]

Nice looks great! Two suggestions to fix the type error and making the unit tests a bit simpler.

[RayBB]

@Harshul23 please request review from drini (as I have done now) or tag him when you're ready for review again (which it seems you are)

[Harshul23]

Thanks I will make sure to re-request a review after addressing changes next time.

[cdrini]

Lgtm! Tested on testing.