Add a reference counter to a structure used internally by the Tcl interface so that it does not segfault if the database connection is closed from any of the various callback scripts that may be invoked.

FossilOrigin-Name: e54a33ce56432b23947583d34cf12fc64a55bbc49eb77c7f33cff5926df51070

test/tclsqlite.test

@@ -848,4 +848,40 @@ do_catchsql_test 19.911 {
 } {1 {invalid command name "bind_fallback_does_not_exist"}}
 db bind_fallback {}
 
+#-------------------------------------------------------------------------
+do_test 20.0 {
+  db transaction {
+    db close
+  }
+} {}
+
+do_test 20.1 {
+  sqlite3 db test.db
+  set rc [catch {
+    db eval {SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3} { db close }
+  } msg]
+  list $rc $msg
+} {1 {invalid command name "db"}}
+  
+
+proc closedb {} {
+  db close
+  return 10
+}
+proc func1 {} { return 1 }
+
+sqlite3 db test.db
+db func closedb closedb
+db func func1 func1
+
+do_test 20.2 {
+  set rc [catch {
+    db eval {
+      SELECT closedb(),func1() UNION ALL SELECT 20,30 UNION ALL SELECT 30,40
+    }
+  } msg]
+  list $rc $msg
+} {0 {10 1 20 30 30 40}}
+
 finish_test
+