Fix mulled-build-files if name_override is not given

lib/galaxy/tool_util/deps/mulled/mulled_build_files.py

@@ -79,6 +79,10 @@ def tuple_from_header(header):
     fields = header[1:].split('\t')
     for field in fields:
         assert field in KNOWN_FIELDS, "'%s' is not one of %s" % (field, KNOWN_FIELDS)
+    # Make sure tuple contains all fields
+    for field in KNOWN_FIELDS:
+        if field not in fields:
+            fields.append(field)
     return collections.namedtuple("_Line", "%s" % " ".join(fields))
 
 

test/unit/tool_util/mulled/test_mulled_build_files.py

@@ -39,6 +39,13 @@ TESTCASES = yaml.safe_load(r"""
       image_build: '10'
       name_override: image_name
       targets: samtools
+- test_files_package_image_build_base_image_with_header:
+    content: "#targets\timage_build\tbase_image\nsamtools\t10\textended_image"
+    equals:
+      base_image: extended_image
+      image_build: '10'
+      name_override: null
+      targets: samtools
 - test_files_package_image_build_name_override_base_image_with_header_reordered:
     content: "#base_image\ttargets\timage_build\tname_override\nextended_image\tsamtools\t10\timage_name"
     equals: