bug#51173: 28.0.60; gnus-article-describe-key doesn't work

[Juri Linkov]

>> +      (let* ((key (read-key-sequence nil t))
>> +                 (buffer (if (consp key)
>> +                             (window-buffer (posn-window (event-start key)))
>> +                           (current-buffer))))
>> +            (describe-key key buffer))))
>
> I think the first `describe-key` above should always use
> `current-buffer` (that's the whole point of the function: to lookup the
> keybinding in that other buffer).

There is still something missing: `gnus-article-describe-key`
already selects the required buffer with `with-current-buffer`.
Then why should it provide the same buffer as an argument
to `describe-key` to select it again in `describe-key`?

Maybe you intended to add a new argument `buffer` to pass it down
to `help--analyze-key` that could use it somehow in this condition:

         (defn (if (consp event)
                   (save-excursion (mouse-set-point event) (key-binding key t))
                 (key-binding key t)))

But I have no idea how.  Maybe not to set point (that also selects
another window) when the `buffer` arg is provided?  E.g.

         (defn (if (not buffer)
                   (save-excursion (mouse-set-point event) (key-binding key t))
                 (key-binding key t)))

IOW, the semantics of `buffer` is not clear here.

> OTOH we should probably try and change the `key` arg to use the new
> key-list format expected by `describe-key` (i.e. a list of (SEQ
> . RAW-SEQ) pairs).

`gnus-article-describe-key` just passes down the value
that `read-key-sequence` returns.