Don't panic when querying with only comments

Author: otoolep

sqlite3.go

@@ -2239,6 +2239,9 @@ func stmtArgs(args []driver.NamedValue, start, na int) []driver.NamedValue {
 }
 
 func (s *SQLiteStmt) bind(args []driver.NamedValue) error {
+	if s.s == nil {
+		return nil
+	}
 	rv := C._sqlite3_reset_clear(s.s)
 	if rv != C.SQLITE_ROW && rv != C.SQLITE_OK && rv != C.SQLITE_DONE {
 		return s.c.lastError()

sqlite3_test.go

@@ -2063,6 +2063,16 @@ func TestNamedParamClearBindings(t *testing.T) {
 	if z.Valid {
 		t.Errorf("Expected z to be NULL, got %d", z.Int64)
 	}
+
+	// Ensure empty statements don't cause panics.
+	_, _ = db.Exec("---- comment")
+	if err != nil {
+		t.Fatal("Failed to exec comment only:", err)
+	}
+	_ = db.QueryRow("---- comment")
+	if err != nil {
+		t.Fatal("Failed to query comment only:", err)
+	}
 }
 
 var customFunctionOnce sync.Once