Fix multiple problems with RETURNING on a DML statement against a view,

all inspired by [forum:/forumpost/dc3b92cfa0|forum post dc3b92cfa0].
(1) Do not allow a RETURNING clause to trick the code generator into thinking
that the view being updated has an INSTEAD OF trigger.
(2) Generate all result columns for a view in a DML statement.
(3) The automatic covering index for a view should cover all result columns
of the view.

FossilOrigin-Name: c8bedef0d61731c29ae34de1594222d15b578f9e2cddbbd5b74fb3059644fe0f

6 files changed, 17 insertions, 8 deletions

diff --git a/src/delete.c b/src/delete.c
index 22ef7ab65..27a554916 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -114,13 +114,15 @@ static int tabIsReadOnly(Parse *pParse, Table *pTab){
 ** If pTab is writable but other errors have occurred -> return 1.
 ** If pTab is writable and no prior errors -> return 0;
 */
-int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
+int sqlite3IsReadOnly(Parse *pParse, Table *pTab, Trigger *pTrigger){
   if( tabIsReadOnly(pParse, pTab) ){
     sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
     return 1;
   }
 #ifndef SQLITE_OMIT_VIEW
-  if( !viewOk && IsView(pTab) ){
+  if( IsView(pTab) 
+   && (pTrigger==0 || (pTrigger->bReturning && pTrigger->pNext==0))
+  ){
     sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
     return 1;
   }
@@ -374,7 +376,7 @@ void sqlite3DeleteFrom(
     goto delete_from_cleanup;
   }
 
-  if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
     goto delete_from_cleanup;
   }
   iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
diff --git a/src/insert.c b/src/insert.c
index 3abf715c9..423af7723 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -796,7 +796,7 @@ void sqlite3Insert(
 
   /* Cannot insert into a read-only table.
   */
-  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
     goto insert_cleanup;
   }
 
@@ -1243,7 +1243,7 @@ void sqlite3Insert(
     }
 
     /* Copy the new data already generated. */
-    assert( pTab->nNVCol>0 );
+    assert( pTab->nNVCol>0 || pParse->nErr>0 );
     sqlite3VdbeAddOp3(v, OP_Copy, regRowid+1, regCols+1, pTab->nNVCol-1);
 
 #ifndef SQLITE_OMIT_GENERATED_COLUMNS
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index d6560c51b..dcf17d963 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -4801,7 +4801,7 @@ Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
                          Expr*,ExprList*,u32,Expr*);
 void sqlite3SelectDelete(sqlite3*, Select*);
 Table *sqlite3SrcListLookup(Parse*, SrcList*);
-int sqlite3IsReadOnly(Parse*, Table*, int);
+int sqlite3IsReadOnly(Parse*, Table*, Trigger*);
 void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
 #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
 Expr *sqlite3LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,char*);
diff --git a/src/trigger.c b/src/trigger.c
index d179d747a..bcb2132f0 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -1453,6 +1453,9 @@ u32 sqlite3TriggerColmask(
   Trigger *p;
 
   assert( isNew==1 || isNew==0 );
+  if( IsView(pTab) ){
+    return 0xffffffff;
+  }
   for(p=pTrigger; p; p=p->pNext){
     if( p->op==op
      && (tr_tm&p->tr_tm)
diff --git a/src/update.c b/src/update.c
index bd1ddb1a3..c1f136398 100644
--- a/src/update.c
+++ b/src/update.c
@@ -408,7 +408,7 @@ void sqlite3Update(
   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
     goto update_cleanup;
   }
-  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
+  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
     goto update_cleanup;
   }
 
diff --git a/src/where.c b/src/where.c
index dd2b8b73c..509d14ff7 100644
--- a/src/where.c
+++ b/src/where.c
@@ -963,7 +963,11 @@ static SQLITE_NOINLINE void constructAutomaticIndex(
   ** original table changes and the index and table cannot both be used
   ** if they go out of sync.
   */
-  extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
+  if( IsView(pTable) ){
+    extraCols = ALLBITS;
+  }else{
+    extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
+  }
   mxBitCol = MIN(BMS-1,pTable->nCol);
   testcase( pTable->nCol==BMS-1 );
   testcase( pTable->nCol==BMS-2 );