add further checks for invalid records

R/parse.R

@@ -76,6 +76,13 @@ read_one <- function(name, path) {
     verlauf <- xml_find_first(x, "sitzungsverlauf")
     speakerl <- xml_find_first(x, "rednerliste")
 
+    # check if record is invalid or empty (every record should have at least
+    # one speech, a speaker and a date
+    if (is.na(date) || length(verlauf) == 0 || length(speakerl) == 0) {
+        warning("Invalid record found. Skipping.")
+        return(NULL)
+    }
+
     xml_children(speakerl) %>%
         parse_speakerlist() ->
         speaker