Tweaked by tabbott to not remove it from lister.py, linter_lib, and
friends, since those are intended to support both Python 2 and 3
(we're planning to extract them from the repository).
In this commit we enhance our current template linter to detect
duplicate ids and report them during lint checks. html_branches.py
was topped up with a new function build_id_dict for the purpose.
Also the get_tag_info function in same file was updated to parse
ids and classes more robustly in cases of template variables.
split_for_id_and_class function was added to serve this purpose.
Unit tests for both the functions were created under
tests/test_html_branches. Also a directory under tests called
test_template_data was created to hold templates for testing under
newly created functionality.
check_templates was modified to print to console any duplicates
detected.
showell reviewed my commit and helped me out.
Fixes#2950.
This code is not directly related to the template parser, so it
can safely live in its own file.
The only significant change to the code is to the signature of
`html_branches` so that it can be called without requiring a file.
Since it's only used in html_grep, that has been updated to reflect
this change.
Fixes: #1774.