- updated/added parameter checks

bin/slubsipbuilderbagit.pl

@@ -96,7 +96,7 @@ package SLUB::LZA::SIPBuilderBagIt;
     ];
 
     sub add_metadata($$$$) {
-        if(! defined $_[0]) { croak "array of hashes not defined for bag-info.txt!"; }
+        if(ref($_[0]) ne 'ARRAY') { croak "array of hashes not defined for bag-info.txt!"; }
 
         my $refAddBagInfo   = $_[0];    # ref to array of hashes
         my $ppn             = $_[1];
@@ -116,6 +116,9 @@ package SLUB::LZA::SIPBuilderBagIt;
     }
 
     sub get_marc21_text_node($$) {
+        if(! $_[0]) { croak "empty marc21!"; }
+        if(ref($_[1]) ne 'HASH') { croak "not a mapping hash!"; }
+
         my $marc21  = $_[0];
         my $mapping = $_[1];
 
@@ -130,9 +133,9 @@ package SLUB::LZA::SIPBuilderBagIt;
     }
 
     sub get_marc21_from_catalogue($){
-        if(! defined $_[0]){ croak "ppn not defined!"; }
+        if(! $_[0]){ croak "ppn not defined!"; }
 
-        my $ppn  = shift;
+        my $ppn = $_[0];
         my $marc21;
         my $use_fallback;
 
@@ -678,7 +681,10 @@ PATCH
     }
 
     sub checkForTitle($){
-        my $key_hash_list_aref = shift;
+        if(ref($_[0]) ne 'ARRAY') { croak "no array of hashes with bag-info.txt key values given!"; }
+
+        my $key_hash_list_aref = $_[0];
+
         # collect all bag-info keys for easy check
         my @keys;
         for my $hash (@{$key_hash_list_aref}) {