Codefences closing improperly when inside GFM alert quotes blocks

[TendTo]

What version of myst-parser are you using?

5.1.0

What version dependencies are you using?

• Sphinx : 9.1.0
• docutils: 0.22.4

What operating system are you using?

Linux

Describe the Bug

It seems that, when using GitHub alerts as admonitions, codefences blocks misbehave.
More specifically, they do not close correctly.

Expected Behavior

Nesting GFM alerts and codefences works as on GitHub and coherently with nesting codefences with other quote blocks (not adminitions).

To Reproduce

Examples

Try rendering the following snippet:

  This works:
  
  :::{note}
  Tip
  
  ```py
  "code"
  ```
  
  other
  
  ```py
  "other code"
  ```
  
  :::
  
  but this doesn't
  
  > [!NOTE]  
  > Note
  >
  > ```py
  > "code"
  > ```
  >
  > other
  >
  > ```py
  > "other code"
  > ```
  
  More in general, there is an issue with code fences not closing correctly, e.g.,
  
  > [!NOTE]  
  > Note
  >
  > ```py
  > code
  > ```
  
  For some reason the code fence extends here too, and stops only at the end of the next code fence.
  
  ```py
  "other code"
  ```
  
  Now I'm finally outside the code fence!
  
  The issue only seems to affect admonitions, as regular quotes work fine:
  
  > Quote (but not an admonition)
  >
  > ```py
  > "code"
  > ```
  >
  > other
  >
  > ```py
  > "other code"
  > ```
  
  and then we are out.

GirHub rendering for reference

This works:

:::{note}
Tip

"code"

other

"other code"

:::

but this doesn't

Note

Note

"code"

other

"other code"

More in general, there is an issue with code fences not closing correctly, e.g.,

Note

Note

code

For some reason the code fence extends here too, and stops only at the end of the next code fence.

"other code"

Now I'm finally outside the code fence!

The issue only seems to affect admonitions, as regular quotes work fine:

Quote (but not an admonition)

"code"

other

"other code"

and then we are out.

[chrisjsewell]

I just added a reproducer (I believe) upstream, and this seems to be working there: executablebooks/markdown-it-py#398

[TendTo]

I would suggest making the content of the block quote longer, something like

> [!NOTE]  
>
> Note
>
> ```py
> "code"
> ```
>
> other
>
> ```py
> "other code"
> ```

because, if it only contains a single fenced block, it seems it works, provided nothing else follows.