fix(docs): stop the version banner showing on the stable docs

[skoudoro]

Closes #141.

Root cause

Not gh-pages, not the deploy workflow — one field in switcher.json.

tools/update_switcher.py appended a synthetic entry and always moved preferred onto it:

{"name": "stable", "version": "stable", "url": ".../stable/", "preferred": true}

But pydata-sphinx-theme gates the version-warning banner on a semver parse of the preferred entry's version field:

// _static/scripts/pydata-sphinx-theme.js (theme 0.21.0)
const t = e => "string" == typeof e && /^[v\d]/.test(e) && o.test(e);  // o = semver regex
...
const s = r[0].version, a = r[0].url;   // "stable", ".../stable/"
const i = t(o) && t(s);                 // t("stable") === false  ->  i === false
if (i && n(o, s, "=")) return;          // suppression branch unreachable
...
m.innerText = o ? `version ${o}` : "an unknown version";

"stable" fails the /^[v\d]/ test, so the suppression branch could never run and every page fell through to the final else. That is the banner in the issue — rendered on /stable/ itself, with a "Switch to stable version" button linking back to the page you are already on.

Fix

Drop the pseudo-version entry. Following the numpy/scipy/pandas convention, the newest release is the stable entry and is served from the /stable/ alias:

[
    {"name": "dev",            "version": "dev",   "url": ".../dev/"},
    {"name": "0.5.0 (stable)", "version": "0.5.0", "url": ".../stable/", "preferred": true},
    {"name": "0.4.0",          "version": "0.4.0", "url": ".../0.4.0/"},
    {"name": "0.3",            "version": "0.3",   "url": ".../0.3/"}
]

This is a pure data fix. Every deployed page fetches switcher.json from the site root at runtime (the URL is hardcoded absolute in conf.py), so correcting the file fixes /stable/, /0.4.0/, /0.3/ and /dev/ retroactively, with no doc rebuild.

Verification

Ran the theme's own regex and predicate, copied verbatim from the deployed bundle, against both the current and the proposed file:

Page	current switcher	this PR
/stable/	banner: "version 0.5.0" ← the bug	no banner
/0.5.0/	banner: "version 0.5.0"	no banner
/0.4.0/	banner: "version 0.4.0"	banner: "an old version (0.4.0)"
/0.3/	banner: "version 0.3"	banner: "an old version (0.3)"
/dev/	banner: "an unstable development version"	unchanged

The old-release banners were wrong for the same reason: with an unparseable preferred version the < comparison could not run either, so they reported a bare version X.Y.Z instead of an old version (X.Y.Z).

Changes

• tools/update_switcher.py — rewritten around build_switcher(). The newest release gets preferred, the " (stable)" name suffix and the /stable/ URL; older releases keep their versioned URL. New parse_version() and is_latest() helpers, and a --rebuild mode. Stdlib only, since the deploy job runs this with the bare runner Python and installs no dependencies.
• .github/workflows/docbuild.yml
  • Read switcher.json from the gh-pages worktree instead of curl-ing the published site. Pages serves that through a CDN cache, so two tags pushed in quick succession could be built from a stale copy and silently drop an entry.
  • Only copy to stable/ when the tag is the newest release, so a backport tag such as 0.4.1 published after 0.5.0 still gets its own folder but cannot demote stable.
  • New workflow_dispatch rebuild-switcher job, so the live site can be fixed without cutting a release. It derives the version list from the folders actually published on gh-pages rather than from git tag -l, because tags 0.0.1–0.2.9 predate the versioned docs and have no folder to link to.
• docs/source/conf.py — version_match collapsed to "dev" if "dev" in version else version. Behaviour is unchanged; the previous form was only accidentally correct.
• trx/tests/test_update_switcher.py — new. update_switcher.py was untested and is the thing that broke. 22 tests, including a named regression test asserting no entry ever carries "version": "stable", plus coverage of the backport guard and --rebuild idempotency.

After merge

Run the workflow manually (Actions → Documentation build → Run workflow) to rewrite switcher.json on gh-pages and fix the live banner. Clear localStorage.pst_banner_pref before checking — the theme remembers dismissals for 14 days and will otherwise mask the result.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.86%. Comparing base (eac5318) to head (6f0002a).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #142      +/-   ##
==========================================
+ Coverage   86.46%   86.86%   +0.40%     
==========================================
  Files          13       14       +1     
  Lines        2881     2970      +89     
==========================================
+ Hits         2491     2580      +89     
  Misses        390      390              

Flag	Coverage Δ
unittests	86.86% <100.00%> (+0.40%)	⬆️

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[arokem]

Thank for doing this!

One question:

Clear localStorage.pst_banner_pref before checking

How/where do I do that? I am not familiar with localStorage.