Certain renderables created with rich.markdown generate AssertionError when rendered in a Widget

[jspv]

If a renderable is created by Rich.Markdown with the following string, "| Simple | Table |\n| ------ | -----" Textual will raise an AssertionError when the Widget is rendered. The following code will demonstrate the problem:

from textual.app import App
from textual.widgets import Static

from rich.markdown import Markdown


# This will work
responses = "| Simple | Table |\n| ------ | ----- |\n| cell1  | cell2 |"

# This will not work
responses = "| Simple | Table |\n| ------ | ----- "


class MDTest(App):
    def compose(self):
        yield Static(Markdown(responses))


app = MDTest()
app.run()

While the offending string is not a properly formatted Markdown table, it should still render the string and not raise an exception. This was discovered trying to render Markdown output that is coming in a stream of word tokens. I've only seen the issue so far with tables, all other Markdown has rendered well, showing the raw strings until there enough tokens arrived to represent the artifact.

textual diagnose

Textual Diagnostics

Versions

Name	Value
Textual	0.29.0
Rich	13.4.2

Python

Name	Value
Version	3.10.12
Implementation	CPython
Compiler	Clang 14.0.3 (clang-1403.0.22.14.1)
Executable	/Users/justin/Library/Caches/pypoetry/virtualenvs/mchat-mvZqEniY-py3.10/bin/python

Operating System

Name	Value
System	Darwin
Release	22.5.0
Version	Darwin Kernel Version 22.5.0: Thu Jun 8 22:22:23 PDT 2023; root:xnu-8796.121.3~7/RELEASE_ARM64_T6020

Terminal

Name	Value
Terminal Application	vscode (1.80.1)
TERM	xterm-256color
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=196, height=20
legacy_windows	False
min_width	1
max_width	196
is_terminal	True
encoding	utf-8
max_height	20
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

[github-actions]

We found the following entries in the FAQ which you may find helpful:

• How do I center a widget in a screen?
• Does Textual support images?
• Why doesn't Textual look good on macOS?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[willmcgugan]

Including the traceback or at least the error message can be very helpful…

[TomJGooding]

The traceback was huge and not particularly useful to be fair. If you run this just with Rich however:

Example code

from rich.console import Console
from rich.markdown import Markdown

# This will work
responses = "| Simple | Table |\n| ------ | ----- |\n| cell1  | cell2 |"

# This will not work
responses = "| Simple | Table |\n| ------ | ----- "

console = Console()
md = Markdown(responses)
console.print(md)

Traceback

Traceback (most recent call last):
  File "/home/tom/Projects/textual-sandbox/repro_3006_console.py", line 12, in <module>
    console.print(md)
  File "/home/tom/Projects/textual-sandbox/.venv/lib/python3.11/site-packages/rich/console.py", line 1699, in print
    extend(render(renderable, render_options))
  File "/home/tom/Projects/textual-sandbox/.venv/lib/python3.11/site-packages/rich/console.py", line 1331, in render
    for render_output in iter_render:
  File "/home/tom/Projects/textual-sandbox/.venv/lib/python3.11/site-packages/rich/markdown.py", line 686, in __rich_console__
    yield from console.render(element, context.options)
  File "/home/tom/Projects/textual-sandbox/.venv/lib/python3.11/site-packages/rich/console.py", line 1331, in render
    for render_output in iter_render:
  File "/home/tom/Projects/textual-sandbox/.venv/lib/python3.11/site-packages/rich/markdown.py", line 262, in __rich_console__
    assert self.body is not None
           ^^^^^^^^^^^^^^^^^^^^^
AssertionError

[jspv]

The traceback was huge and not particularly useful to be fair. If you run this just with Rich however:

Thanks! I'll move this over to Rich.

[github-actions]

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