MIN Slightly better error message

Specify which FASTA file the error occurred in when contig ID already
contains the separator character

/cc #143

ChangeLog

@@ -1,6 +1,8 @@
 Unreleased
 	* SemiBin: Write a log file
 	* concatenate_fasta: support compression
+	* concatenate_fasta: slightly better error message when contig ID already
+	contains separator
 
 Version 1.5.1 (SemiBin2 beta) Mar 7 2023 by BigDataBiology
 	* Bugfix: using --no-recluster with multi_easy_bin (#128)

SemiBin/utils.py

@@ -541,17 +541,19 @@ def get_model_path(env):
 def concatenate_fasta(fasta_files, min_length, output, separator, output_compression='none'):
     """
     Concatenate multiple FASTA files into one
+
+    Returns name of the concatenated file
     """
     ofname = os.path.join(output, 'concatenated.fa')
     if output_compression != 'none':
         ofname += '.' + output_compression
     with possibly_compressed_write(ofname) as concat_out:
-        for fasta in fasta_files:
-            sample_name = os.path.basename(fasta).split('.')[0]
-            for h, seq in fasta_iter(fasta):
+        for fname in fasta_files:
+            sample_name = os.path.basename(fname).split('.')[0]
+            for h, seq in fasta_iter(fname):
                 if separator in h:
                     sys.stderr.write(
-                        f"Error: the header of the contig '{h}' contains the separator ('{separator}'), please choose another separator.\n")
+                        f"Error in file {fname}: Contig ID '{h}' contains the separator ('{separator}'), please choose another separator.\n")
                     sys.exit(1)
                 if len(seq) >= min_length:
                     header = f'{sample_name}{separator}{h}'