grep: added taxonomy check

python/obitools3/commands/grep.pyx

@@ -258,6 +258,13 @@ def Filter_generator(options, tax_filter, i_view):
 
 
 def Taxonomy_filter_generator(taxo, options):
+    
+    if (("required_ranks" in options and options["required_ranks"]) or \
+       ("required_taxids" in options and options["required_taxids"]) or \
+       ("ignored_taxids" in options and options["ignored_taxids"])) and \
+       (taxo is None):
+        raise RollbackException("obi grep error: can't use taxonomy options without providing a taxonomy. Rollbacking view")
+    
     if taxo is not None:
         def tax_filter(seq):
             good = True