When commands such as ALTER TABLE and VACUUM use SQL internally, make sure

they use only the built-in functions and not application-defined overrides
for those functions.

FossilOrigin-Name: 0291ed974d5bf1e344e2c38422530cc961b897da

5 files changed, 33 insertions, 14 deletions

diff --git a/src/alter.c b/src/alter.c
index 694b243bd..359c4e737 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -226,17 +226,23 @@ static void renameTriggerFunc(
 /*
 ** Register built-in functions used to help implement ALTER TABLE
 */
-void sqlite3AlterFunctions(sqlite3 *db){
-  sqlite3CreateFunc(db, "sqlite_rename_table", 2, SQLITE_UTF8, 0,
-                         renameTableFunc, 0, 0);
+void sqlite3AlterFunctions(void){
+  static SQLITE_WSD FuncDef aAlterTableFuncs[] = {
+    FUNCTION(sqlite_rename_table,   2, 0, 0, renameTableFunc),
 #ifndef SQLITE_OMIT_TRIGGER
-  sqlite3CreateFunc(db, "sqlite_rename_trigger", 2, SQLITE_UTF8, 0,
-                         renameTriggerFunc, 0, 0);
+    FUNCTION(sqlite_rename_trigger, 2, 0, 0, renameTriggerFunc),
 #endif
 #ifndef SQLITE_OMIT_FOREIGN_KEY
-  sqlite3CreateFunc(db, "sqlite_rename_parent", 3, SQLITE_UTF8, 0,
-                         renameParentFunc, 0, 0);
+    FUNCTION(sqlite_rename_parent,  3, 0, 0, renameParentFunc),
 #endif
+  };
+  int i;
+  FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
+  FuncDef *aFunc = (FuncDef*)&GLOBAL(FuncDef, aAlterTableFuncs);
+
+  for(i=0; i<ArraySize(aAlterTableFuncs); i++){
+    sqlite3FuncDefInsert(pHash, &aFunc[i]);
+  }
 }
 
 /*
@@ -380,7 +386,9 @@ void sqlite3AlterRenameTable(
   char *zWhere = 0;         /* Where clause to locate temp triggers */
 #endif
   VTable *pVTab = 0;        /* Non-zero if this is a v-tab with an xRename() */
-  
+  int savedDbFlags;         /* Saved value of db->flags */
+
+  savedDbFlags = db->flags;  
   if( NEVER(db->mallocFailed) ) goto exit_rename_table;
   assert( pSrc->nSrc==1 );
   assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
@@ -389,6 +397,7 @@ void sqlite3AlterRenameTable(
   if( !pTab ) goto exit_rename_table;
   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
   zDb = db->aDb[iDb].zName;
+  db->flags |= SQLITE_PreferBuiltin;
 
   /* Get a NULL terminated version of the new table name. */
   zName = sqlite3NameFromToken(db, pName);
@@ -556,6 +565,7 @@ void sqlite3AlterRenameTable(
 exit_rename_table:
   sqlite3SrcListDelete(db, pSrc);
   sqlite3DbFree(db, zName);
+  db->flags = savedDbFlags;
 }
 
 
@@ -675,9 +685,11 @@ void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
   zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
   if( zCol ){
     char *zEnd = &zCol[pColDef->n-1];
+    int savedDbFlags = db->flags;
     while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
       *zEnd-- = '\0';
     }
+    db->flags |= SQLITE_PreferBuiltin;
     sqlite3NestedParse(pParse, 
         "UPDATE \"%w\".%s SET "
           "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
@@ -686,6 +698,7 @@ void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
       zTab
     );
     sqlite3DbFree(db, zCol);
+    db->flags = savedDbFlags;
   }
 
   /* If the default value of the new column is NULL, then set the file
diff --git a/src/callback.c b/src/callback.c
index e6c51bccd..c016959fd 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -353,14 +353,19 @@ FuncDef *sqlite3FindFunction(
 
   /* If no match is found, search the built-in functions.
   **
+  ** If the SQLITE_PreferBuiltin flag is set, then search the built-in
+  ** functions even if a prior app-defined function was found.  And give
+  ** priority to built-in functions.
+  **
   ** Except, if createFlag is true, that means that we are trying to
   ** install a new function.  Whatever FuncDef structure is returned will
   ** have fields overwritten with new information appropriate for the
   ** new function.  But the FuncDefs for built-in functions are read-only.
   ** So we must not search for built-ins when creating a new function.
   */ 
-  if( !createFlag && !pBest ){
+  if( !createFlag && (pBest==0 || (db->flags & SQLITE_PreferBuiltin)!=0) ){
     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
+    bestScore = 0;
     p = functionSearch(pHash, h, zName, nName);
     while( p ){
       int score = matchQuality(p, nArg, enc);
diff --git a/src/func.c b/src/func.c
index 7ff1fecb0..7bd3d58fa 100644
--- a/src/func.c
+++ b/src/func.c
@@ -1416,9 +1416,6 @@ static void groupConcatFinalize(sqlite3_context *context){
 ** external linkage.
 */
 void sqlite3RegisterBuiltinFunctions(sqlite3 *db){
-#ifndef SQLITE_OMIT_ALTERTABLE
-  sqlite3AlterFunctions(db);
-#endif
   if( !db->mallocFailed ){
     int rc = sqlite3_overload_function(db, "MATCH", 2);
     assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
@@ -1592,4 +1589,7 @@ void sqlite3RegisterGlobalFunctions(void){
     sqlite3FuncDefInsert(pHash, &aFunc[i]);
   }
   sqlite3RegisterDateTimeFunctions();
+#ifndef SQLITE_OMIT_ALTERTABLE
+  sqlite3AlterFunctions();
+#endif
 }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 6007b8af9..6e6ec72ac 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -913,6 +913,7 @@ struct sqlite3 {
 #define SQLITE_RecTriggers    0x02000000  /* Enable recursive triggers */
 #define SQLITE_ForeignKeys    0x04000000  /* Enforce foreign key constraints  */
 #define SQLITE_AutoIndex      0x08000000  /* Enable automatic indexes */
+#define SQLITE_PreferBuiltin  0x10000000  /* Preference to built-in funcs */
 
 /*
 ** Bits of the sqlite3.flags field that are used by the
@@ -2881,7 +2882,7 @@ extern int sqlite3PendingByte;
 #endif
 void sqlite3RootPageMoved(Db*, int, int);
 void sqlite3Reindex(Parse*, Token*, Token*);
-void sqlite3AlterFunctions(sqlite3*);
+void sqlite3AlterFunctions(void);
 void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
 int sqlite3GetToken(const unsigned char *, int *);
 void sqlite3NestedParse(Parse*, const char*, ...);
diff --git a/src/vacuum.c b/src/vacuum.c
index 1d3b998c6..12a07e9c8 100644
--- a/src/vacuum.c
+++ b/src/vacuum.c
@@ -117,7 +117,7 @@ int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
   saved_nChange = db->nChange;
   saved_nTotalChange = db->nTotalChange;
   saved_xTrace = db->xTrace;
-  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;
+  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks | SQLITE_PreferBuiltin;
   db->flags &= ~(SQLITE_ForeignKeys | SQLITE_ReverseOrder);
   db->xTrace = 0;