Fix a problem causing a crash if an fts5vocab table was created to query an

fts3/4 FTS index.

FossilOrigin-Name: 9cd64ce453e4435d80117b8610c22a0a4b53cd6e84b39815e70e684f6b0295c8

ext/fts5/fts5_main.c

@@ -2244,13 +2244,13 @@ Fts5Index *sqlite3Fts5IndexFromCsrid(
   Fts5Config **ppConfig           /* OUT: Configuration object */
 ){
   Fts5Cursor *pCsr;
-  Fts5Table *pTab;
-
   pCsr = fts5CursorFromCsrid(pGlobal, iCsrId);
-  pTab = (Fts5Table*)pCsr->base.pVtab;
-  *ppConfig = pTab->pConfig;
-
-  return pTab->pIndex;
+  if( pCsr ){
+    Fts5Table *pTab = (Fts5Table*)pCsr->base.pVtab;
+    *ppConfig = pTab->pConfig;
+    return pTab->pIndex;
+  }
+  return 0;
 }
 
 /*

ext/fts5/test/fts5vocab2.test

@@ -202,4 +202,36 @@ do_execsql_test 3.5 {
   SELECT * FROM v1;
 } {}
 
+#-------------------------------------------------------------------------
+#
+reset_db
+do_execsql_test 4.0 {
+  CREATE VIRTUAL TABLE v1 USING fts5vocab(nosuchtable, col);
+}
+
+do_catchsql_test 4.1 {
+  SELECT * FROM v1 WHERE term=='nosuchterm';
+} {1 {no such fts5 table: main.nosuchtable}}
+
+do_execsql_test 4.2.1 {
+  CREATE TABLE nosuchtable(nosuchtable, y, z);
+}
+do_catchsql_test 4.2.2 {
+  SELECT * FROM v1 WHERE term=='nosuchterm';
+} {1 {no such fts5 table: main.nosuchtable}}
+
+ifcapable fts3 {
+  do_execsql_test 4.3.1 {
+    DROP TABLE nosuchtable;
+    CREATE VIRTUAL TABLE nosuchtable USING fts3(a, b);
+  } {}
+  do_catchsql_test 4.3.2 {
+    SELECT * FROM v1 WHERE term=='nosuchterm';
+  } {1 {no such fts5 table: main.nosuchtable}}
+  do_catchsql_test 4.3.3 {
+    INSERT INTO nosuchtable VALUES('id', '*id');
+    SELECT * FROM v1 WHERE term=='nosuchterm';
+  } {1 {no such fts5 table: main.nosuchtable}}
+}
+
 finish_test