fix(custom-gauges): filter multi-state border gauges on the custom page

[mousebrains]

Fast-follow to #96 (review flagged this sibling issue).

Why

#96 makes border gauges (gauge.state = 'OR,WA' — the whole Columbia mainstem) selectable in the gauge picker. Their destination, custom_gauges.php?ids=…, carried the same exact-match state handling the picker had, so a selected border gauge landed on a page that couldn't filter it:

• _compute_custom_gauges_filters() — isset(CUSTOM_GAUGES_STATE_ABBREVS['OR,WA']) is false → no state pill.
• row render — CUSTOM_GAUGES_STATE_ABBREVS['OR,WA'] ?? '' → empty $state, so the if ($state !== '' && $huc8 !== '') guard emitted no data-state/data-huc8 → the row escaped both the state and watershed filters.
• the State filter group lacked data-split="csv", so even a comma data-state wouldn't have matched a pill.

Milder than the picker bug (the gauge still rendered its flow/gage), but it dropped its pills and ignored the filters.

Fix — same three-spot mirror of the static build (web/build/gauges.py, levels.py:469)

• pills: split gauge.state on the comma so each state contributes a pill.
• row: map each abbrev → full name, re-join → data-state="Oregon,Washington".
• State group: add data-split="csv" so filters.js splits the row value to match each pill.

No schema or data change — purely how the page reads the existing state column.

Tests

CustomGaugesIntegrationTest gains an OR,WA seed gauge and asserts a single border gauge surfaces both Oregon and Washington pills, the State group is data-split="csv", and the row renders as a filterable row (data-state="Oregon,Washington" data-huc8="17080003").

Local gate (green)

• custom-gauges tests 15/15 · full PHP suite 520/520, 2106 assertions · PHPStan L9+strict clean · php-cs-fixer clean

Independent of #96 (different files); merges in any order.

🤖 Generated with Claude Code

[mousebrains]

Code Review — #97 fix(custom-gauges): filter multi-state border gauges on the custom page

Verdict: ✅ Approve. This is a faithful, minimal implementation of the fast-follow I flagged in the #96 review — it fixes the exact three spots, in the right way, with a test that pins the contract. I re-verified each against the code rather than taking the description on faith.

Verified

• The three spots match the diagnosis. _compute_custom_gauges_filters() now splits state_abbrev so a border gauge contributes both pills; the row render splits → maps → re-joins to data-state="Oregon,Washington"; and the State group gains data-split="csv". That trio is precisely what was needed, and it mirrors the static build (gauges.py + levels.py:469 split_csv=True).
• The end-to-end path is sound. I'd already confirmed in fix(picker): show multi-state border gauges in the gauge picker #96 that filters.js keys splitCSV off container.dataset.split === 'csv' and that matches() splits the row value on comma — so a data-state="Oregon,Washington" row now matches either the Oregon or Washington pill. The count($states_present) > 1 gate means a lone border gauge still renders the State group (2 pills), which the test relies on.
• $state scoping is clean. The now comma-joined $state is used only by the if ($state !== '' && $huc8 !== '') guard and the data-state attribute (lines 441–442, htmlspecialchars-escaped) — it's never echoed into a visible cell, so no "Oregon,Washington" text leaks into the table. A border gauge with a HUC clears the guard and emits both data-state + data-huc8, so it's a filterable row.

The typing subtlety — done right

#96's picker fix needed (string)($row['state_abbrev'] ?? '') because those PDO rows are untyped (mixed). #97 correctly omits the cast: the custom-gauges rows are explicitly shaped (@param list<array{state_abbrev: string|null, …}>, lines 205/374), so $r['state_abbrev'] ?? '' is already a string and explode() gets a string — L9-strict stays clean. Nice that this wasn't blindly copied from the picker.

Tests

testBorderGaugeSurfacesBothStatesAndStaysFilterable pins the right server-side contract: both pills emitted from a single OR,WA seed, the data-group="state" data-split="csv" attribute, and the filterable-row regex data-state="Oregon,Washington"\s+data-huc8="17080003". The seed is realistic (Columbia/Vancouver, real HUC). No server-side negative test is needed here (unlike #96, the page is id-based, not state-filtered server-side — there's no anchoring to guard); the actual pill-matching is the shared filters.js splitCSV path, already exercised by the static page.

Note

• mergeStateStatus is currently UNSTABLE — CI looks to still be settling. Worth confirming it goes CLEAN (as fix(picker): show multi-state border gauges in the gauge picker #96 did) before merging. The change itself is independent of fix(picker): show multi-state border gauges in the gauge picker #96 and merges in any order.

🤖 Reviewed with Claude Code