Fix an issue with RETURNING from UPSERT.

FossilOrigin-Name: 757b74ba0fd64634a365bd73955181191767ad8816a33a362e32ece250299a51

manifest

@@ -1,5 +1,5 @@
-C Snapshot.\s\sNew\sdesign\sappears\sto\swork\son\sa\ssimple\stest\scase.
-D 2021-02-04T20:52:20.449
+C Fix\san\sissue\swith\sRETURNING\sfrom\sUPSERT.
+D 2021-02-04T21:17:12.237
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -607,7 +607,7 @@ F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c c64c49d7c2ec4490c2fef1f24350167ba16b03b0c6cee58ad1a1d70a4325d4e9
 F src/treeview.c 4b92992176fb2caefbe06ba5bd06e0e0ebcde3d5564758da672631f17aa51cda
-F src/trigger.c 5da6ba6d4067b5dcdd11a6da37ce3cb56586df75a7be685efb534c46d5c773c8
+F src/trigger.c f7c383d955433ecb8b4e1469578e559585b08c846cfeb7c1e9a3fa54d6872c0e
 F src/update.c 0f5a61f0787199983530a33f6fffe4f52742f35fcdf6ccfad1078b1a8bc17723
 F src/upsert.c df8f1727d62b5987c4fd302cd4d7c0c84ae57cd65683c5a34a740dfe24039235
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
@@ -1899,7 +1899,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 04b77d63216ce11b4e797946953bcde504fc005807c7a5ac757fbf47d78698dc
-R 3969643abefe6509994dc8b8c75efd08
+P 8a65fbeecf3597e30853c5f0ccd9b8b46c508854fa521e58e0db279deebca7d4
+R d02a9b42befb5b25aa3638c6334cc03d
 U drh
-Z b4647d4c6645877bc3632b5ebc38eb6e
+Z fef4d4b17488be8894b2080187642bf5

manifest.uuid

@@ -1 +1 @@
-8a65fbeecf3597e30853c5f0ccd9b8b46c508854fa521e58e0db279deebca7d4
+757b74ba0fd64634a365bd73955181191767ad8816a33a362e32ece250299a51

src/trigger.c

@@ -857,7 +857,7 @@ static ExprList *sqlite3ExpandReturning(
       }
     }
   }
-  if( !db->mallocFailed ){
+  if( !db->mallocFailed && !pParse->colNamesSet ){
     Vdbe *v = pParse->pVdbe;
     assert( v!=0 );
     sqlite3VdbeSetNumCols(v, pNew->nExpr);
@@ -888,14 +888,14 @@ static void codeReturningTrigger(
   assert( pParse->bReturning );
   pReturning = pParse->u1.pReturning;
   assert( pTrigger == &(pReturning->retTrig) );
-  sqlite3VdbeAddOp0(v, OP_Noop);
-  VdbeComment((v, "RETURNING trigger goes here"));
   pNew = sqlite3ExpandReturning(pParse, pReturning->pReturnEL, pTab);
   if( pNew ){
     NameContext sNC;
     memset(&sNC, 0, sizeof(sNC));
+    if( pReturning->nRetCol==0 ){
       pReturning->nRetCol = pNew->nExpr;
       pReturning->iRetCur = pParse->nTab++;
+    }
     sNC.pParse = pParse;
     sNC.uNC.iBaseReg = regIn;
     sNC.ncFlags = NC_UBaseReg;