[BUG?] unsupported operand type(s) for +: 'ParentNode' and 'int'

[oliver-sanders]

Description:

My use case is no longer working with urwid 2.6.2/3. The breakage appears to come from this change:

https://github.com/urwid/urwid/pull/824/files#diff-4c88378f9ea5730d04299a47d1ddd0842ae43a8dbaba7bdaf78e3b7762078189R674

Where self._body.get_next was replaced by bottom_pos + 1. In my case bottom_pos is a ParentNode not an integer, resulting in a TypeError.

It looks like the get_next interface is a more generic solution, the TreeWalker.get_next implementation appears to be expecting some form of TreeNode which suggests the integer type might not be a safe assumption:

urwid/urwid/treetools.py

Lines 423 to 429 in 36bf037

	# pylint: disable=arguments-renamed # its bad, but we should not change API
	def get_next(self, start_from) -> tuple[TreeWidget, TreeNode] | tuple[None, None]:
	target = start_from.get_widget().next_inorder()
	if target is None:
	return None, None
	return target, target.get_node()

I don't have a minimal reproducible example at present, I'm not sure if this is somehow resulting from misuse of urwid, hence BUG?.

Affected versions (if applicable)

• master branch (specify commit)
• Latest stable version from pypi - 2.6.2 & 2.6.3
• Other (specify source)

Steps to reproduce (if applicable)

No minimal reproducible example at present.

Expected/actual outcome

No TypeError.

[wardi]

That's right we shouldn't have code that assumes position is an integer in ListBox