bug#59545: 29.0.50; Eshell fails to redirect output of sourced eshell file

[Jim Porter]

On 12/23/2022 11:29 PM, Jim Porter wrote:
> I found a problem with the patch on master:
>
>    ~ $ {echo hello; echo world} | rev
>    olleh  ;; "dlrow" is missing!
>
> This happens because the way I'm copying output handles around results 
> in EOF being sent to "rev" after "echo hello".

Attached is a patch to fix this. I'm going to look into adding more test 
cases if I can think of any before merging this.

I'll also see if I can fix the FIXME comment I added, but this is a part 
of Eshell that's fairly brittle, and I think the *real* fix for that is 
moving to running Eshell commands in a separate thread, as discussed on 
emacs-devel. (I have a very WIP patch for this that already works 
surprisingly well, but it's going to require a lot more work before it's 
even worth making a feature branch.)

0001-Fix-reference-counting-of-Eshell-I-O-handles.patch
Description: Text document