[abhishekcpp007]

#42 made the marker detection accept any GFM whitespace after [ ] / [x], so a tab or form feed now counts as a task. make_checkbox still checks startswith("[ ] ") and startswith("[x] ") with a literal space, so neither branch matches. The item gets the task-list-item class, [ ] is stripped, and an empty html_inline goes where the checkbox should be.

from markdown_it import MarkdownIt
from mdit_py_plugins.tasklists import tasklists_plugin

MarkdownIt().use(tasklists_plugin).render("- [ ]\tfoo\n")

On 0.7.0:

<li class="task-list-item">\tfoo</li>

The checkbox is gone, and so is the marker. With label=True, label_after=True it's worse: content[0:-1] + ' id="..."' runs on the empty string, so the raw text id="task-item-…"> shows up in the page:

<li class="task-list-item"> id="task-item-775e…"><label class="task-list-item-label" for="task-item-775e…">\tfoo</label></li>

starts_with_todo_markdown has already matched [ ], [x] or [X] plus whitespace by the time make_checkbox runs, so the fix only looks at the character inside the brackets.

The "Tab after" and "Form feed after" fixtures from #42 had recorded the output without the checkbox. They now expect the <input> like the space case does. test_label_after_is_escaped gains a tab case for each of unchecked and checked.

Verified in a python:3.12 container with pip install -e ".[testing]":

• master: 728 passed, 3 skipped, 1 xfailed
• this branch: 730 passed, 3 skipped, 1 xfailed
• the updated tests against master's mdit_py_plugins: 4 failed (both fixtures and both new label_after cases)