Immediately fail a CREATE TABLE statement that attempts to create a

table that has a generated column loop.  Legacy allows the table to be
created but the table would not be usable for anything.

FossilOrigin-Name: 3237bf964117c1ef71143042837ef21872bb3d04bfd682075672e768953ec802

src/build.c

@@ -2920,6 +2920,13 @@ void sqlite3EndTable(
     /* Reparse everything to update our internal data structures */
     sqlite3VdbeAddParseSchemaOp(v, iDb,
            sqlite3MPrintf(db, "tbl_name='%q' AND type!='trigger'", p->zName),0);
+
+    /* Test for cycles in generated columns */
+    if( p->tabFlags & TF_HasGenerated ){
+      sqlite3VdbeAddOp4(v, OP_SqlExec, 0, 0, 0,
+             sqlite3MPrintf(db, "SELECT*FROM\"%w\".\"%s\"",
+                   db->aDb[iDb].zDbSName, p->zName), P4_DYNAMIC);
+    }
   }
 
   /* Add the table to the in-memory representation of the database.