f29b65452a1cca8a5bc62f007100b313e589d036
braney
  Sun Sep 6 15:11:36 2026 -0700
quickLift: lift a bigNet track, refs #20824

A net is not an ordinary track to lift.  It is an alignment of two assemblies,
so only its target side moves to the new reference; the query side names a third
assembly and is carried across untouched.  And the browser draws a net by
recursion, so what really has to survive the lift is the tree: a row's level only
means anything relative to the row above it.

chainNetLoadRangeQuickLift() maps each row's target range with
quickLiftIntervalsToBedClip, which is the same code every other quickLift track
uses, so a net row lands where a bed of the same span would.  The surviving rows
then go to the same helpToNet() the unlifted path uses, so there is one tree
builder and not two.  The row collection either path does is now cnlHelperNew and
cnlHelperAddBigNet.

validateOneTdb lets bigNet into a quickLift hub.  Its chain track is not offered,
so a lifted net's details page has no chain to follow and says so rather than
looking for a track this assembly does not have.  bigNetLoadOne lifts the same
way for that page, unclipped, so it reports the item's whole extent.

bigNetFromInterval passes -1 as the cached chromId.  bbiCachedChromLookup leaves
the buffer alone when the id matches the one before it, so a cache that outlives
the buffer hands back stale bytes.

Measured against the standalone liftOver tool, on hg19 chr22's mouse net lifted
to hg38: 36 of 36 source rows in the sampled window land on the same coordinates,
counting the one liftOver will not take whole, whose two ends it does place
exactly where the browser puts them.  Against hg38's own mouse net, computed
independently, 1.02% of the drawn pixels differ.

diff --git src/hg/hgc/hgc.h src/hg/hgc/hgc.h
index 09e11dd6b76..251fde51f21 100644
--- src/hg/hgc/hgc.h
+++ src/hg/hgc/hgc.h
@@ -87,33 +87,30 @@
  * and other parameters. */
 
 void hgcAnchorWindow(char *group, char *item, int thisWinStart,
         int thisWinEnd, char *other, char *chrom);
 /* Generate an anchor that calls click processing program with item
  * and other parameters, INCLUDING the ability to specify left and
  * right window positions different from the current window*/
 
 void hgcAnchor(char *group, char *item, char *other);
 /* Generate an anchor that calls click processing program with item
  * and other parameters. */
 
 struct trackDb *tdbForTableArg();
 /* get trackDb for track passed in table arg */
 
-struct trackDb *getTdbForTrackName(char *trackName);
-/* Given a track name (which may have ct_ or hub_ prepended), return its tdb. */
-
 void writeFramesetType();
 /* Write document type that shows a frame set, rather than regular HTML. */
 
 void htmlFramesetStart(char *title);
 /* Write DOCTYPE HTML and HEAD sections for framesets. */
 
 void alnModernStart(char *classicTitle);
 /* Begin an alignment page: modern single-page chrome when the modernAlignPage hg.conf flag is set
  * (showSomeAlignment then renders the modern body), else the classic <frameset>. */
 
 struct psl *getAlignments(struct sqlConnection *conn, char *table, char *acc);
 /* get the list of alignments for the specified acc */
 
 void printAlignmentsSimple(struct psl *pslList, int startFirst, char *hgcCommand,
                            char *typeName, char *itemIn);