Whenever a generated column is used, assume that all columns are used.

FossilOrigin-Name: 6601da58032d18ae00b466c0f2077fb2b1ecd84225b56e1787724bea478eedc9

1 files changed, 17 insertions, 3 deletions

diff --git a/src/resolve.c b/src/resolve.c
index 9be62c090..fbfdf118e 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -551,9 +551,18 @@ static int lookupName(
 
   /* If a column from a table in pSrcList is referenced, then record
   ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
-  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
-  ** column number is greater than the number of bits in the bitmask
-  ** then set the high-order bit of the bitmask.
+  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.
+  **
+  ** The colUsed mask is an optimization used to help determine if an
+  ** index is a covering index.  The correct answer is still obtained
+  ** if the mask contains extra bits.  But omitting bits from the mask
+  ** might result in an incorrect answer.
+  **
+  ** The high-order bit of the mask is a "we-use-them-all" bit.
+  ** If the column number is greater than the number of bits in the bitmask
+  ** then set the high-order bit of the bitmask.  Also set the high-order
+  ** bit if the column is a generated column, as that adds dependencies
+  ** that are difficult to track, so we assume that all columns are used.
   */
   if( pExpr->iColumn>=0 && pMatch!=0 ){
     int n = pExpr->iColumn;
@@ -561,7 +570,12 @@ static int lookupName(
     if( n>=BMS ){
       n = BMS-1;
     }
+    assert( pExpr->y.pTab!=0 );
     assert( pMatch->iCursor==pExpr->iTable );
+    if( pExpr->y.pTab->tabFlags & TF_HasGenerated ){
+      Column *pCol = pExpr->y.pTab->aCol + pExpr->iColumn;
+      if( pCol->colFlags & COLFLAG_GENERATED ) n = BMS-1;
+    }
     pMatch->colUsed |= ((Bitmask)1)<<n;
   }