fix(district): stop attributing docket uploads to a stale cached case id

[playfulart]

What this fixes

When a district docket report page yields no case id from its own context (URL, inputs, referrer), handleDocketDisplayPage falls back to the per-tab cached case id and uploads the entire page HTML under it. That cached value can belong to a different case viewed earlier in the same tab — nothing invalidates it on navigation — so one case's full docket sheet gets uploaded under another case's pacer_case_id, and the archive faithfully merges one case's entire history (entries and parties) into the other's docket.

Real-world occurrence

This happened to a pro se litigant's case in D. Nev.: the complete docket of Empire Trust v. Cellura (nvd 3:25-cv-00553, pacer_case_id 177277) was uploaded under Mitchell v. Tate's id (nvd 2:26-cv-00720, pacer_case_id 180126). CourtListener docket 72456248 now contains ~165 entries byte-identical (same entry numbers, dates, text, and pacer_doc_ids) to entries on docket 71566874, including the foreign case's SDNY pre-transfer history and two of its parties. Both CL docket records carry correct, distinct pacer_case_ids, so the wrong id had to be attached client-side at upload time. A data-repair request for that docket was sent separately via the CourtListener contact form.

The fix

Before reaching for the cached id, derive the case id from the page itself: a district docket sheet carries its own case id in every document link's goDLS() onclick handler. New helper PACER.getCaseIdFromDocketDisplayLinks() tallies those ids, and the fallback path in handleDocketDisplayPage now prefers that evidence over the tab cache:

• The plurality (most common) id wins, so a stray link to another case's document — legitimate on consolidated/MDL sheets (the existing comment in findAndStorePacerDocIds notes this corner case) — cannot outvote the sheet itself.
• A tie counts as no evidence — the cached-id fallback applies as before rather than guessing.
• An id the page context already provided is never overridden. On consolidated member dockets the document links legitimately point at the lead case, so the goDLS plurality is only trusted when there is no context id at all. This keeps the change strictly scoped to the previously-unprotected fallback path — behavior on every other path is byte-for-byte unchanged.
• When the page id beats a conflicting cached id, a console warning says so, and the cached id is corrected, seeding the right id for a later docket-report load in the same tab.
• Pages with no goDLS evidence behave exactly as before (some courts don't emit goDLS).

Tests

Five new specs in ContentDelegateSpec.js:

• stale tab-cached id + page links assert another id → upload uses the page's id, nothing is sent under the stale id, and the cached id is corrected in storage;
• consolidated member docket shape: context-derived id present + goDLS plurality pointing at the lead case → context id wins (never overridden);
• consolidated plurality: three links to the lead case + one stray member-case link → most common id used;
• tied ids → no guessing, cached-id fallback preserved;
• fresh tab with no storage record at all → no throw, no upload (regression for the missing-record guard caught in review).

Full suite: 188/188 passing (183 pre-existing + 5 new). CHANGES.md updated under Upcoming → Fixes.

Review round 1 (@ERosendo)

All four suggestions adopted, one commit each: the sort-based rewrite of getCaseIdFromDocketDisplayLinks, the plurality (not strict-majority) doc wording, the corrected comment on what the tab-storage write feeds (a later docket-report load — attachment menus resolve via docsToCases, verified), and the || {} guard on getItemsFromStorage with the regression spec above.

[CLAassistant]

All committers have signed the CLA.

[ERosendo]

Thanks for putting this together! it's a nice improvement, and it should address the stale cache issue from freelawproject/courtlistener#5247.

I left a few small suggestions, mostly around hardening and documentation, but I think the overall approach looks great.

[playfulart]

@ERosendo Thanks for the review! All four suggestions are in, one commit each: your rewrite of getCaseIdFromDocketDisplayLinks verbatim (121ecfa), the plurality wording (29e4871), the corrected tab-storage comment (8e8be8f), and the || {} guard plus a regression spec for the fresh-tab path (9d02f4d). Suite is 188/188 locally. Ready for another look — CI just needs a maintainer to approve the workflow runs.

[MargoSchlanger]

Another one of these: https://www.courtlistener.com/docket/63890699/american-civil-liberties-union-v-united-states-immigration-and-customs/
It combines the dockets for ACLU v. ICE, 3:18-cv-01200 (N.D. Cal.) (this is the one that should be there) and some other case against "GPL Servicing, Ltd.".

[mlissner]

Thanks Margo. Can you please take a look, Eduardo?

[albertisfu]

Thanks @MargoSchlanger! The reported case has been cleaned up.