Combination of blockquotes, list and newlines causes an IndexError

[anttimaki]

Describe the bug

This is a bit of an edge case I encountered while rendering a README file. I was able to remove irrelevant parts, until just this was left:

> QUOTE\n
+ UNORDERED LIST ITEM\n
  > INDENTED QUOTE\n
\n\n

This causes an IndexError. Removing any one of the three rows with content causes the example to work as expected. Also removing on or more newlines from the end causes the example to work. It's just this combination that causes problems.

Reproduce the bug

from markdown_it import MarkdownIt
md = MarkdownIt("gfm-like")
md.render("> QUOTE\n+ UNORDERED LIST ITEM\n  > INDENTED QUOTE\n\n\n")

Error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/venv/lib/python3.8/site-packages/markdown_it/main.py", line 275, in render
    return self.renderer.render(self.parse(src, env), self.options, env)
  File "/venv/lib/python3.8/site-packages/markdown_it/main.py", line 260, in parse
    self.core.process(state)
  File "/venv/lib/python3.8/site-packages/markdown_it/parser_core.py", line 33, in process
    rule(state)
  File "/venv/lib/python3.8/site-packages/markdown_it/rules_core/block.py", line 14, in block
    state.md.block.parse(
  File "/venv/lib/python3.8/site-packages/markdown_it/parser_block.py", line 107, in parse
    self.tokenize(state, state.line, state.lineMax)
  File "/venv/lib/python3.8/site-packages/markdown_it/parser_block.py", line 77, in tokenize
    if rule(state, line, endLine, False):
  File "/venv/lib/python3.8/site-packages/markdown_it/rules_block/list.py", line 272, in list_block
    prevEmptyEnd = (state.line - startLine) > 1 and state.isEmpty(state.line - 1)
  File "/venv/lib/python3.8/site-packages/markdown_it/rules_block/state_block.py", line 137, in isEmpty
    return (self.bMarks[line] + self.tShift[line]) >= self.eMarks[line]
IndexError: list index out of range

List your environment

• Python 3.8.10
• markdown-it-py 1.1.0 (also occurs on 2.0.1)

[welcome]

Thanks for opening your first issue here! Engagement like this is essential for open source projects! 🤗

If you haven't done so already, check out EBP's Code of Conduct. Also, please try to follow the issue template as it helps other community members to contribute more effectively.

If your issue is a feature request, others may react to it, to raise its prominence (see Feature Voting).

Welcome to the EBP community! 🎉

[mib112]

May be related to #205

Matching test case for this error (expected result taken from javascript markdon-it):

Issue#204.  Combination of blockquotes, list and newlines causes an IndexError
.
> QUOTE
+ UNORDERED LIST ITEM
  > INDENTED QUOTE



.
<blockquote>
<p>QUOTE</p>
</blockquote>
<ul>
<li>UNORDERED LIST ITEM
<blockquote>
<p>INDENTED QUOTE</p>
</blockquote>
</li>
</ul>
.