Merge trunk into wasi-patches branch.

FossilOrigin-Name: 656d36f50f630da68262469087bad1ac71b10325e233a7963103c8cbc232f61a

1 files changed, 11 insertions, 8 deletions

diff --git a/src/select.c b/src/select.c
index d27bed026..b0e303066 100644
--- a/src/select.c
+++ b/src/select.c
@@ -5626,9 +5626,6 @@ static int resolveFromTermToCte(
     pFrom->fg.isCte = 1;
     pFrom->u2.pCteUse = pCteUse;
     pCteUse->nUse++;
-    if( pCteUse->nUse>=2 && pCteUse->eM10d==M10d_Any ){
-      pCteUse->eM10d = M10d_Yes;
-    }
 
     /* Check if this is a recursive CTE. */
     pRecTerm = pSel = pFrom->pSelect;
@@ -6911,8 +6908,10 @@ static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
 **                    being used as the outer loop if the sqlite3WhereBegin()
 **                    routine nominates it to that position.
 **              (iii) The query is not a UPDATE ... FROM
-**    (2)  The subquery is not a CTE that should be materialized because of
-**         the AS MATERIALIZED keywords
+**    (2)  The subquery is not a CTE that should be materialized because
+**         (a) the AS MATERIALIZED keyword is used, or
+**         (b) the CTE is used multiple times and does not have the
+**             NOT MATERIALIZED keyword
 **    (3)  The subquery is not part of a left operand for a RIGHT JOIN
 **    (4)  The SQLITE_Coroutine optimization disable flag is not set
 **    (5)  The subquery is not self-joined
@@ -6924,9 +6923,13 @@ static int fromClauseTermCanBeCoroutine(
   int selFlags            /* Flags on the SELECT statement */
 ){
   SrcItem *pItem = &pTabList->a[i];
-  if( pItem->fg.isCte && pItem->u2.pCteUse->eM10d==M10d_Yes ) return 0;/* (2) */
-  if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0;                /* (3) */
-  if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0;  /* (4) */
+  if( pItem->fg.isCte ){
+    const CteUse *pCteUse = pItem->u2.pCteUse;
+    if( pCteUse->eM10d==M10d_Yes ) return 0;                          /* (2a) */
+    if( pCteUse->nUse>=2 && pCteUse->eM10d!=M10d_No ) return 0;       /* (2b) */
+  }
+  if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0;               /* (3)  */
+  if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0; /* (4)  */
   if( isSelfJoinView(pTabList, pItem, i+1, pTabList->nSrc)!=0 ){
     return 0;                                                          /* (5) */
   }