fix(district): attribute docket uploads by the page's own goDLS case id

The docket report upload previously trusted a pacer_case_id derived from
the referrer or cached in per-tab storage. Both values can belong to a
different case viewed earlier in the same tab, and when that happened the
entire docket sheet of one case was uploaded under another case's id,
merging one case's full history into the other's archive docket.
Observed in the wild: all ~165 entries of nvd 3:25-cv-00553 were merged
into nvd 2:26-cv-00720 (CourtListener docket 72456248), including the
other case's parties.

A district docket sheet already asserts its own case id: every document
link carries it in the goDLS() onclick handler. Tally those ids and
attribute the upload by the strict majority, so a stray link to another
case's document (legitimate on consolidated/MDL sheets) cannot outvote
the sheet itself; a tie falls back to the previous behavior rather than
guessing. When the page id wins over a conflicting inherited id, warn on
the console and heal the tab's cached case id so later pages in the tab
(e.g. attachment menus, which have no case id of their own) inherit the
right one. Pages with no goDLS evidence behave exactly as before.

Author: Bryan Mitchell

CHANGES.md

@@ -11,7 +11,12 @@ Changes:
  - None yet
 
 Fixes:
- - None yet
+ - Attribute district docket report uploads by the case id the page's own
+   goDLS document links assert, instead of a referrer-derived or per-tab
+   cached case id that can belong to a different case viewed earlier in
+   the same tab. Prevents one case's docket sheet from being uploaded
+   under another case's `pacer_case_id` and merged into the wrong archive
+   docket.
 
 For developers:
  - Nothing yet

spec/ContentDelegateSpec.js

@@ -596,6 +596,16 @@ describe('The ContentDelegate class', function () {
       });
 
       describe('when the docket page is not an interstitial page', function () {
+        const makeLink = (caseId, docId) => {
+          const a = document.createElement('a');
+          a.href = `https://ecf.canb.uscourts.gov/doc1/${docId}`;
+          a.setAttribute(
+            'onclick',
+            `goDLS('/doc1/${docId}','${caseId}','5','','','1','','','');` +
+              'return(false);'
+          );
+          return a;
+        };
         beforeEach(function () {
           clearDocumentBody();
           table = document.createElement('table');
@@ -670,6 +680,131 @@ describe('The ContentDelegate class', function () {
           expect(button.length).toBe(1);
         });
 
+        it('prefers the goDLS case id over a stale tab id', async function () {
+          // The tab's cached caseId ('531591' in the storage mock)
+          // belongs to another case; the page's goDLS links must win.
+          const link = makeLink('177277', '034031424909');
+          const cd = new ContentDelegate(
+            tabId,
+            docketDisplayUrl,
+            docketDisplayPath,
+            'canb',
+            undefined, // no case id derived from url/referrer/inputs
+            undefined,
+            [link]
+          );
+          dispatchBackgroundNotifier = jasmine.createSpy();
+          dispatchBackgroundFetch = jasmine
+            .createSpy()
+            .and.callFake(fakeBackgroundFetch);
+          spyOn(history, 'replaceState');
+          await cd.handleDocketDisplayPage();
+          expect(dispatchBackgroundFetch).toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              action: 'upload',
+              data: jasmine.objectContaining({ pacer_case_id: '177277' }),
+            })
+          );
+          expect(dispatchBackgroundFetch).not.toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              data: jasmine.objectContaining({ pacer_case_id: '531591' }),
+            })
+          );
+          // the stale cached id is corrected for later pages in this tab
+          expect(window.chrome.storage.local.set).toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              1234: jasmine.objectContaining({ caseId: '177277' }),
+            }),
+            jasmine.any(Function)
+          );
+        });
+
+        it('overrides a conflicting id with the goDLS id', async function () {
+          // Same protection when a wrong id arrived at initialization
+          // (e.g. parsed from the referrer of a previously viewed case).
+          const link = makeLink('177277', '034031424909');
+          const cd = new ContentDelegate(
+            tabId,
+            docketDisplayUrl,
+            docketDisplayPath,
+            'canb',
+            '531591', // stale id from another case
+            undefined,
+            [link]
+          );
+          dispatchBackgroundNotifier = jasmine.createSpy();
+          dispatchBackgroundFetch = jasmine
+            .createSpy()
+            .and.callFake(fakeBackgroundFetch);
+          spyOn(history, 'replaceState');
+          await cd.handleDocketDisplayPage();
+          expect(dispatchBackgroundFetch).toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              action: 'upload',
+              data: jasmine.objectContaining({ pacer_case_id: '177277' }),
+            })
+          );
+        });
+
+        it('uses the majority goDLS id on merged sheets', async function () {
+          // Consolidated/MDL dockets legitimately link member cases'
+          // documents — a stray link must not outvote the sheet.
+          const cd = new ContentDelegate(
+            tabId,
+            docketDisplayUrl,
+            docketDisplayPath,
+            'canb',
+            undefined,
+            undefined,
+            [
+              makeLink('177277', '034031424909'),
+              makeLink('177277', '034031424910'),
+              makeLink('177277', '034031424911'),
+              makeLink('999999', '034031424912'), // stray member-case link
+            ]
+          );
+          dispatchBackgroundNotifier = jasmine.createSpy();
+          dispatchBackgroundFetch = jasmine
+            .createSpy()
+            .and.callFake(fakeBackgroundFetch);
+          spyOn(history, 'replaceState');
+          await cd.handleDocketDisplayPage();
+          expect(dispatchBackgroundFetch).toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              action: 'upload',
+              data: jasmine.objectContaining({ pacer_case_id: '177277' }),
+            })
+          );
+        });
+
+        it('falls back when the goDLS ids are tied', async function () {
+          // Equal votes for two ids: don't guess; keep the old behavior.
+          const cd = new ContentDelegate(
+            tabId,
+            docketDisplayUrl,
+            docketDisplayPath,
+            'canb',
+            '531591',
+            undefined,
+            [
+              makeLink('177277', '034031424909'),
+              makeLink('888888', '034031424910'),
+            ]
+          );
+          dispatchBackgroundNotifier = jasmine.createSpy();
+          dispatchBackgroundFetch = jasmine
+            .createSpy()
+            .and.callFake(fakeBackgroundFetch);
+          spyOn(history, 'replaceState');
+          await cd.handleDocketDisplayPage();
+          expect(dispatchBackgroundFetch).toHaveBeenCalledWith(
+            jasmine.objectContaining({
+              action: 'upload',
+              data: jasmine.objectContaining({ pacer_case_id: '531591' }),
+            })
+          );
+        });
+
         it('calls uploadDocket and responds to a negative result', async function () {
           const cd = docketDisplayContentDelegate;
           dispatchBackgroundNotifier = jasmine.createSpy();

src/content_delegate.js

@@ -269,12 +269,28 @@ ContentDelegate.prototype.handleDocketDisplayPage = async function () {
   // check if appellate
   // let isAppellate = PACER.isAppellateCourt(this.court);
 
-  // if the content_delegate didn't pull the case Id on initialization,
-  // check the page for a lead case dktrpt url.
-  const tabStorage = await getItemsFromStorage(this.tabId);
-  this.pacer_case_id = this.pacer_case_id
-    ? this.pacer_case_id
-    : tabStorage.caseId;
+  // Prefer the case id the page asserts about itself (via its goDLS
+  // links) over the referrer-derived or tab-cached id — either of those
+  // can belong to a different case viewed earlier in this tab.
+  const pageCaseId = PACER.getCaseIdFromDocketDisplayLinks(this.links);
+  if (pageCaseId) {
+    if (this.pacer_case_id && this.pacer_case_id !== pageCaseId) {
+      console.warn(
+        `RECAP: Not attributing this docket to case ${this.pacer_case_id}: ` +
+          'its own document links say it belongs to case ' +
+          `${pageCaseId}. Using ${pageCaseId}.`
+      );
+    }
+    this.pacer_case_id = pageCaseId;
+    // Refresh the cached id so caseless pages downstream (e.g. attachment
+    // menus) inherit the right one.
+    await saveCaseIdinTabStorage({ tabId: this.tabId }, pageCaseId);
+  } else if (!this.pacer_case_id) {
+    // if the content_delegate didn't pull the case Id on initialization,
+    // check the tab storage for a lead case dktrpt url.
+    const tabStorage = await getItemsFromStorage(this.tabId);
+    this.pacer_case_id = tabStorage.caseId;
+  }
 
   // If we don't have this.pacer_case_id at this point, punt.
   if (!this.pacer_case_id) return;

src/pacer.js

@@ -462,6 +462,35 @@ let PACER = {
     }
   },
 
+  // Returns the case id a docket report page asserts about itself: the
+  // strict majority of the de_caseid values in its document links' goDLS()
+  // handlers. Majority, because consolidated/MDL sheets legitimately link
+  // member cases' documents. Returns undefined when there is no goDLS
+  // evidence or the top ids are tied.
+  getCaseIdFromDocketDisplayLinks: function (links) {
+    let tally = {};
+    for (let i = 0; i < links.length; i++) {
+      if (!PACER.isDoc1Url(links[i].href)) {
+        continue;
+      }
+      let goDLS = PACER.parseGoDLSFunction(links[i].getAttribute('onclick'));
+      if (goDLS && goDLS.de_caseid && goDLS.de_caseid !== '0') {
+        tally[goDLS.de_caseid] = (tally[goDLS.de_caseid] || 0) + 1;
+      }
+    }
+    let best;
+    let tied = false;
+    for (let caseId of Object.keys(tally)) {
+      if (best === undefined || tally[caseId] > tally[best]) {
+        best = caseId;
+        tied = false;
+      } else if (tally[caseId] === tally[best]) {
+        tied = true;
+      }
+    }
+    return tied ? undefined : best;
+  },
+
   // Given a URL that satisfies isDocketQueryUrl, gets its case number.
   getCaseNumberFromUrls: function (urls) {
     // Iterate over an array of URLs and get the case number from the