4 files changed, 24 insertions, 13 deletions
diff --git a/src/alter.c b/src/alter.c
index 0a82327d6..38446f998 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -31,9 +31,8 @@
 static int isAlterableTable(Parse *pParse, Table *pTab){
   if( 0==sqlite3StrNICmp(pTab->zName, "sqlite_", 7) 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-   || ( (pTab->tabFlags & TF_Shadow) 
-     && (pParse->db->flags & SQLITE_Defensive)
-     && pParse->db->nVdbeExec==0
+   || ( (pTab->tabFlags & TF_Shadow)!=0
+        && sqlite3ReadOnlyShadowTables(pParse->db)
    )
 #endif
   ){
diff --git a/src/build.c b/src/build.c
index 2cc00d9d8..05b753dbb 100644
--- a/src/build.c
+++ b/src/build.c
@@ -2895,17 +2895,32 @@ void sqlite3CodeDropTable(Parse *pParse, Table *pTab, int iDb, int isView){
 }
 
 /*
+** Return TRUE if shadow tables should be read-only in the current
+** context.
+*/
+int sqlite3ReadOnlyShadowTables(sqlite3 *db){
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  if( (db->flags & SQLITE_Defensive)!=0
+   && db->pVtabCtx==0
+   && db->nVdbeExec==0
+  ){
+    return 1;
+  }
+#endif
+  return 0;
+}
+
+/*
 ** Return true if it is not allowed to drop the given table
 */
-static int tableMayNotBeDropped(Parse *pParse, Table *pTab){
+static int tableMayNotBeDropped(sqlite3 *db, Table *pTab){
   if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
     if( sqlite3StrNICmp(pTab->zName+7, "stat", 4)==0 ) return 0;
     if( sqlite3StrNICmp(pTab->zName+7, "parameters", 10)==0 ) return 0;
     return 1;
   }
-  if( pTab->tabFlags & TF_Shadow ){
-    sqlite3 *db = pParse->db;
-    if( (db->flags & SQLITE_Defensive)!=0 && db->nVdbeExec==0 ) return 1;
+  if( (pTab->tabFlags & TF_Shadow)!=0 && sqlite3ReadOnlyShadowTables(db) ){
+    return 1;
   }
   return 0;
 }
@@ -2979,7 +2994,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
     }
   }
 #endif
-  if( tableMayNotBeDropped(pParse, pTab) ){
+  if( tableMayNotBeDropped(db, pTab) ){
     sqlite3ErrorMsg(pParse, "table %s may not be dropped", pTab->zName);
     goto exit_drop_table;
   }
diff --git a/src/delete.c b/src/delete.c
index a18026712..0a83f1b64 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -70,11 +70,7 @@ static int tabIsReadOnly(Parse *pParse, Table *pTab){
     return sqlite3WritableSchema(db)==0 && pParse->nested==0;
   }
   assert( pTab->tabFlags & TF_Shadow );
-  return (db->flags & SQLITE_Defensive)!=0 
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-          && db->pVtabCtx==0
-#endif
-          && db->nVdbeExec==0;
+  return sqlite3ReadOnlyShadowTables(db);
 }
 
 /*
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 73dbdbfc7..1ec1018a5 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -4547,6 +4547,7 @@ void sqlite3AutoLoadExtensions(sqlite3*);
    );
 #  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
 #endif
+int sqlite3ReadOnlyShadowTables(sqlite3 *db);
 int sqlite3VtabEponymousTableInit(Parse*,Module*);
 void sqlite3VtabEponymousTableClear(sqlite3*,Module*);
 void sqlite3VtabMakeWritable(Parse*,Table*);