09f26ed9a7dcc52b03b4d3e5b2f97c5177cd9334
max
  Mon Sep 21 06:00:40 2026 -0700
Drop the ${hgsid} trackDb variable; add session ids to links in the browser instead

A description page's links can carry the session id without the page itself holding
one.  addHgsidToLinks() in utils.js walks the rendered page and appends hgsid to every
<a href> that stays on this host and points into the same cgi-bin directory: a relative
CGI link gets one, a static .html, a link to another host, a mailto and a plain #anchor
do not, and a link that already names a session is left alone.  hgc and hgTrackUi call
it through a new jsAddHgsidToLinks(), and hgTracks.js calls it on the track description
popup once the ajax content is in.  A link written with a literal $hgsid is rewritten
rather than skipped, so the description pages already deployed in the GenArk hubs work
again.

hVarSubst no longer knows about hgsid: it is out of the trackDb variable list, so
hVarSubstTrackDbHtml is a hub-only pass again and needs no cart, and hVarSubstWithCart
and webIncludeHelpFileSubst, which existed only to resolve it, are gone.  The variable
is taken out of the trackDb README and out of the twenty-odd description pages that
used it.

refs #38380

diff --git src/hg/hgTrackUi/hgTrackUi.c src/hg/hgTrackUi/hgTrackUi.c
index ad5c3dbea05..d7edeb8f5e5 100644
--- src/hg/hgTrackUi/hgTrackUi.c
+++ src/hg/hgTrackUi/hgTrackUi.c
@@ -3740,31 +3740,31 @@
 
 printf("<b>Configure track container: "
            "<img height=12 src='../images/ab_up.gif'>"
             "<a href='%s?%s=%s&db=%s&c=%s&g=%s'>%s </a></b>",
             hgTrackUiName(), cartSessionVarName(), cartSessionId(cart),
             database, chromosome, cgiEncode(tdbParent->track), tdbParent->longLabel);
 printf("<p>");
 
 if (tdbIsFacetedComposite(tdb))
     return;
 
 if (tdbParent->html)
     {
     // the excerpt below is the container's own description page, so it needs the same
     // substitution the track's page gets further down
-    hVarSubstTrackDbHtml(cart, tdbParent, database);
+    hVarSubstTrackDbHtml(tdbParent, database);
     // collapsed panel for Description
     printf("<p><table>");  // required by jsCollapsible
     jsBeginCollapsibleSectionFontSize(cart, tdb->track, "superDescription", "Description", FALSE,
                                             "medium");
     // TODO: better done with regex
     char *html = replaceChars(tdbParent->html, "<H", "<h");
     html = replaceChars(html, "</H", "</h");
 
     // remove Description header
     html = replaceChars(html, "<h2>Description</h2>", "");
     html = replaceChars(html, "<h3>Description</h3>", "");
     html = replaceChars(html, "<h1>Description</h1>", "");
 
     // remove everything after Description text
     char *end = stringIn("<h2>", html);
@@ -3862,47 +3862,47 @@
 
 // NOTE: Currently only composite multi-view tracks because
 // reset relies upon all cart vars following naming convention:
 //   {track}.{varName}...  ( One exception supported: {track}_sel ).
 
 if (trackDbLocalSetting(tdb, "container"))
     {
     /* For the moment, be a composite... */
     tdbMarkAsComposite(tdb);
     }
 if (ajax && cartOptionalString(cart, "descriptionOnly"))
     {
     char *liftDb = cloneString(trackDbSetting(tdb, "quickLiftDb"));
     if (liftDb)
         tdb->html = getTrackHtml(liftDb, tdb->table);
-    // resolve $hgsid, and for a hub the rest of its description page variables
-    hVarSubstTrackDbHtml(cart, tdb, database);
+    // a hub's description page has not been substituted yet
+    hVarSubstTrackDbHtml(tdb, database);
     //struct trackDb *tdbParent = tdbFillInAncestry(cartString(cart, "db"),tdb);
     if (tdb->html != NULL && tdb->html[0] != 0)
         {
         printRelatedTracks(database,trackHash,tdb,cart);
         puts(tdb->html);
         }
     else
         {
         struct trackDb *tdbParent = tdb->parent;
         for (;tdbParent && (tdbParent->html == NULL || tdbParent->html[0] == 0);
               tdbParent = tdbParent->parent )
             ; // Get the first parent that has html
         if (tdbParent != NULL && tdbParent->html != NULL && tdbParent->html[0])
             {
-            hVarSubstTrackDbHtml(cart, tdbParent, database);
+            hVarSubstTrackDbHtml(tdbParent, database);
             printf("<h2 style='color:%s'>Retrieved from %s Track...</h2>\n",
                    COLOR_DARKGREEN,tdbParent->shortLabel);
             printRelatedTracks(database,trackHash,tdb,cart);
             puts(tdbParent->html);
             }
         else
             printf("<h2>No description found for: %s.</h2>",tdbParent?tdbParent->track:tdb->track);
         }
     cartRemove(cart,"descriptionOnly"); // This is a once only request and should be deleted
     return;
     }
 if (tdbIsContainer(tdb) || tdbIsSuperTrack(tdb))
     {
     safef(setting,sizeof(setting),"%s.%s",tdb->track,RESET_TO_DEFAULTS);
     // NOTE: if you want track vis to not be reset, move to after vis dropdown
@@ -4295,32 +4295,32 @@
 
     char *genome = hGenome(database);
     char *desc = hFreezeDateOpt(database);
     printf("<b>Assembly:</b> %s %s<br>", genome, desc);
 
     /* Print lift information from trackDb, if any */
     trackDbPrintOrigAssembly(tdb, database);
 
     printUpdateTime(database, tdb, NULL);
     }
 
 char *liftDb = cloneString(trackDbSetting(tdb, "quickLiftDb"));
 // quickLiftChain has static html
 if (liftDb && differentString(trackHubSkipHubName(tdb->track), "quickLiftChain"))
     tdb->html = getTrackHtml(liftDb, tdb->table);
-// resolve $hgsid, and for a hub the rest of its description page variables
-hVarSubstTrackDbHtml(cart, tdb, database);
+// a hub's description page has not been substituted yet
+hVarSubstTrackDbHtml(tdb, database);
 if (tdb->html != NULL && tdb->html[0] != 0)
     {
     char *browserVersion;
     if (btIE == cgiClientBrowser(&browserVersion, NULL, NULL) && *browserVersion < '8')
         htmlHorizontalLine();
     else // Move line down, since <H2>Description (in ->html) is proceded by too much space
         printf("<HR ALIGN='bottom' style='position:relative; top:1em;'>");
 
     printf("<table class='windowSize'><tr valign='top'><td rowspan=2>");
     puts("<A NAME='TRACK_HTML'></A>");    // include anchor for Description link
 
     // Add pennantIcon
     printPennantIconNote(tdb);
 
     char *html = tdb->html;
@@ -4772,30 +4772,31 @@
                 "<span style='background-color: #c3d4f4; "
                     "padding-left: 10px; padding-right: 10px;"
                     "margin-right: 10px; margin-left: -8px;'>"
                        "%s</span> %s", 
                 htmlEncode(tdb->parent->shortLabel), htmlEncode(tdb->shortLabel));
         }
     else
         dyStringPrintf(title, "%s", htmlEncode(tdb->shortLabel));
     char *titleEnd = (tdbIsSuper(tdb) ? "Tracks" :
                tdbIsDownloadsOnly(tdb) ? DOWNLOADS_ONLY_TITLE : "Track Settings");
     htmlNoEscape();     // allow HTML tags to format title blue bar (using short label)
     cartWebStart(cart, database, "%s %s", title->string, titleEnd);
     htmlDoEscape();
     trackUi(tdb, tdbList, ct, FALSE);
     printf("<BR>\n");
+    jsAddHgsidToLinks();
     jsonPrintGlobals();
     webEnd();
     }
 }
 
 char *excludeVars[] = { "submit", "Submit", "g", "fileUrl", "track", "sourceDb", NULL, "ajax", NULL,};
 
 int main(int argc, char *argv[])
 /* Process command line. */
 {
 long enteredMainTime = clock1000();
 /* 0, 0, == use default 10 second for warning, 20 second for immediate exit */
 issueBotWarning = earlyBotCheck(enteredMainTime, "hgTrackUi", delayFraction, 0, 0, "html");
 cgiSpoof(&argc, argv);
 cartEmptyShellNoContent(doMiddle, hUserCookie(), excludeVars, NULL);