Re: tramp (2.6.1 HEAD/3ff676c2f98cb6c47fecb37f31a589a910dd3876); docker-container ssh multi-hop support

[Gene Goykhman]

I've made some progress and have published a gist with my current approach to 
multi-hop Docker container completion in TRAMP. I'd appreciate comments and 
suggestions, and whether this is a reasonable direction to take or if I'm 
missing something important.

  https://gist.github.com/genegoykhman/09868acd369b3fae866be6446997de9f

I've taken an approach similar to the one Kristofer describes ...

> A very simple change I tried when previously trying to get multihop
> completion working
> with another backend was that if I changed the variable
> `tramp-compat-temporary-file-directory'
> for the function `temporary-file-directory' in the completion
> functions (like `tramp-container--completion-function'), then at least

I'm advising :before tramp-completion-handle-file-name-all-completions and 
parsing out the required remote directory from which we need to call the docker 
program to get remote completions. Then, I'm adding a custom completion 
function my-tramp-container-completion-function that takes that directory (if 
it has been parsed) and sets it as the default-directory.

> Another issue that I found, which maybe is unavoidable, is that some
> of the completion functions in `tramp-container' requires that the
> container
> program is installed on the local host, but sometimes I only have

I /think/ the approach I've taken only requires that the container program be 
available on the remote host on which we are trying to get the completion list.

Feedback appreciated!