fix: handle presence of tab characters on TODO line

Ensure alignment of issue URL line is correct even
when the TODO line had any number of tab
characters prior to the issue title

Addresses remaining sub-issues of and
closes GitHub issue #245

TodoParser.py

@@ -393,6 +393,13 @@ def _get_file_details(self, file):
                     return syntax_details, ace_mode
         return None, None
 
+    def _tabs_and_spaces(self, num_tabs: int, num_spaces: int) -> str:
+        """
+        Helper function which returns a string containing the
+        specified number of tabs and spaces (in that order)
+        """
+        return '\t'*num_tabs + ' '*num_spaces
+
     def _extract_issue_if_exists(self, comment_block, marker, hunk_info):
         """Check this comment for TODOs, and if found, build an Issue object."""
         curr_issue = None
@@ -403,7 +410,11 @@ def _extract_issue_if_exists(self, comment_block, marker, hunk_info):
         for line_number_within_comment_block, line in enumerate(comment_lines):
             line_status, committed_line = self._get_line_status(line)
             line_statuses.append(line_status)
-            cleaned_line, pre_marker_length, post_marker_length = self._clean_line(committed_line, marker)
+            (cleaned_line,
+             pre_marker_length,
+             num_pre_marker_tabs,
+             post_marker_length,
+             num_post_marker_tabs) = self._clean_line(committed_line, marker)
             line_title, ref, identifier, identifier_actual = self._get_title(cleaned_line)
             if line_title:
                 if prev_line_title and line_status == line_statuses[-2]:
@@ -423,7 +434,9 @@ def _extract_issue_if_exists(self, comment_block, marker, hunk_info):
                                 + comment_block['start'] + line_number_within_comment_block),
                     start_line_within_hunk=comment_block['start'] + line_number_within_comment_block + 1,
                     num_lines=1,
-                    prefix=(' '*pre_marker_length)+(marker['pattern'] if marker['type'] == 'line' else '')+(' '*post_marker_length),
+                    prefix=self._tabs_and_spaces(num_pre_marker_tabs, (pre_marker_length-num_pre_marker_tabs)) +
+                           str(marker['pattern'] if marker['type'] == 'line' else '') +
+                           self._tabs_and_spaces(num_post_marker_tabs, post_marker_length-num_post_marker_tabs),
                     markdown_language=hunk_info['markdown_language'],
                     status=line_status,
                     identifier=identifier,
@@ -534,6 +547,7 @@ def _get_line_status(self, comment):
     def _clean_line(comment, marker):
         """Remove unwanted symbols and whitespace."""
         post_marker_length = 0
+        num_post_marker_tabs = 0
         if marker['type'] == 'block':
             original_comment = comment
             comment = comment.strip()
@@ -546,15 +560,19 @@ def _clean_line(comment, marker):
                 comment = comment.lstrip('*')
             comment = comment.strip()
             pre_marker_length = original_comment.find(comment)
+            num_pre_marker_tabs = comment.count('\t', 0, pre_marker_length)
         else:
             comment_segments = re.search(fr'^(.*?)({marker["pattern"]})(\s*)(.*?)\s*$', comment)
             if comment_segments:
                 pre_marker_text, _, post_marker_whitespace, comment = comment_segments.groups()
                 pre_marker_length = len(pre_marker_text)
+                num_pre_marker_tabs = pre_marker_text.count('\t', 0, pre_marker_length)
                 post_marker_length = len(post_marker_whitespace)
+                num_post_marker_tabs = post_marker_whitespace.count('\t', 0, post_marker_length)
             else:
                 pre_marker_length = 0
-        return comment, pre_marker_length, post_marker_length
+                num_pre_marker_tabs = 0
+        return comment, pre_marker_length, num_pre_marker_tabs, post_marker_length, num_post_marker_tabs
 
     def _get_title(self, comment):
         """Check the passed comment for a new issue title (and reference, if specified)."""