Maintenance roadmap: compatibility, branches, CI, and releases

[waddell]

UDST is resuming active maintenance of UrbanAccess.

Several contributors continued compatibility and feature work while regular maintenance was inactive. We appreciate those efforts. Contributions incorporated into UrbanAccess will retain clear authorship and release-note credit.

Initial priorities:

• define UrbanAccess's maintained scope and relationship to Pandana, OSMnet, and current transit/network tooling
• review and reconcile the accumulated work in PR compat for new pandas #94 and its source branches
• restore compatibility with current Pandas and supported Python versions
• coordinate NumPy 2 support with the Pandana compatibility release
• establish a tested dependency range
• restore fast, deterministic CI and separate network-dependent tests
• modernize packaging metadata and remove Python 2 declarations
• review PR Feature/networkx helpers #91 and the underlying NetworkX converter branch as a separate feature proposal
• resolve the obsolete Docker proposal in PR Provide Dockerfile #18 and issue Dockerfile for repo #12
• reconcile dev, master, and outstanding feature branches
• establish main as the protected integration branch
• prepare and publish a maintenance release
• restore automated PyPI and Conda-forge distribution

PR #94 is the primary source for recovery work, but it should not be merged as-is. It combines 79 commits and approximately four years of previously unmerged UDST branch work with newer compatibility changes. An initial Python 3.12 validation installed successfully, but current dependency combinations exposed both the released Pandana NumPy 2 ABI blocker and substantial remaining Pandas compatibility failures. The work should be decomposed, credited, and validated through a modern CI baseline.

PR #91 targets an unmerged feature branch rather than the integration branch and should be reconsidered after the maintenance baseline is established. PR #18 targets the obsolete master branch and proposes a 2017 development image that should not be adopted as current infrastructure.

This issue will remain open until UrbanAccess has an operational maintenance, test, branch, packaging, and release process.

[waddell]

Proposed decomposition of PR #94

PR #94 will remain open as the provenance and reference PR while its accumulated work is recovered through an ordered series of reviewable pull requests. @sablanchard is the UDST technical owner for PRs 1–8.

• PR 1 — Modern packaging and deterministic CI

  • establish supported Python versions and a known working dependency envelope
  • remove Python 2 declarations
  • add package build and installed-package tests
  • separate deterministic required tests from network-dependent tests

• PR 2 — GTFS download, ZIP handling, configuration, and validation

  • recover the coherent work from enhancement/download-refactor
  • preserve original commit authorship where practical
  • include the corresponding feed download and validation tests

• PR 3 — GTFS identifiers, dtypes, whitespace handling, and shapes.txt support

  • recover the agency-ID and feed-ID fixes
  • incorporate feature/shapes-txt
  • test missing optional files, malformed values, dtype conversion, and multiple feeds

• PR 4 — Calendar and service-selection logic

  • recover feature/expand-cal-service-id-extraction
  • keep the calendar implementation and its extensive tests together
  • validate calendar-only, calendar-dates-only, combined, date-range, and highest-frequency cases

• PR 5 — Network utilities and integration

  • recover enhancement/network_utils
  • expose and test reusable connector and nearest-neighbor utilities
  • validate network integration independently of external downloads

• PR 6 — Transit-network simplification

  • recover feature/simplify-transit-net
  • build on the calendar and network-utility PRs
  • include behavioral and topology regression tests

• PR 7 — Direction-aware headways and memory improvements

  • recover @jessicacamacho's direction, memory, and append-removal commits
  • test both directions, route types, and headway integration

• PR 8 — Current Pandas compatibility sweep

  • retain or explicitly credit @knaaptime's compatibility commits
  • replace removed APIs and positional-indexing assumptions throughout the recovered code
  • address current dtype and copy-on-write behavior
  • test the full deterministic suite across the declared Pandas range

• PR 9 — NumPy 2 and current Pandana integration

  • begin after the Pandana compatibility release is available
  • test NumPy 1 and 2 only if both remain in the declared support contract
  • exercise installed Pandana and an end-to-end accessibility smoke test

• PR 10 — Documentation, migration notes, and release preparation

  • document restored and changed behavior
  • provide upgrade guidance and supported-version policy
  • prepare release notes with complete contributor credit

Integration rules

• Start with a known working dependency envelope; do not make unreleased Pandana compatibility a prerequisite for all recovery work.
• Land implementation and its associated tests together.
• Preserve original commit authorship through cherry-picking when the history can be retained cleanly.
• When changes must be rewritten, identify the source branch and authors explicitly in the PR body and release notes.
• Each replacement PR must link compat for new pandas #94 and this roadmap issue.
• Do not close compat for new pandas #94 until every incorporated branch and commit has been either recovered, explicitly deferred, or rejected with a documented reason.
• After the series is complete, close compat for new pandas #94 as superseded with links to the replacement PRs; do not characterize the contribution as rejected.