> coding.c:7777     (*(coding->encoder)) (coding);
>
> Here `coding->encoder` is 0. I then printed `*coding` but I don't have
> enough understanding to figure out what's wrong with it.
>

Okay, Emacs works if I in term.c:753 if I use this:

```
coding = FRAME_TERMINAL_CODING (f);
```

instead of:

```
coding = (FRAME_TERMINAL_CODING (f)->common_flags &
CODING_REQUIRE_ENCODING_MASK ? FRAME_TERMINAL_CODING (f) :
&safe_terminal_coding);
```

I know docker allocates a "pseudo TTY", so probably that there's a
misdetection happening here. The thing is it works for all docker images <=
26.2, so something changed in Emacs that triggers this only for docker's
TTY.

Getting close :-)
Philippe

p.s: I noticed that earlier I replied to Eli only, so I'm sending again the
gdb backgrace with the lisp backtrace to the ML

>