tags 41721 + patch
found 41721 27.0.50
quit

Platon Pronko <platon7pronko@gmail.com> writes:

> 1. 'emacs -Q'
> 2. 'M-x list-packages'
> 3. 'f'
> 4. Observe message "f is undefined"

This is because Emacs 27 introduced new filtering commands under the '/'
prefix, so the old binding 'f' no longer exists:

Filter packages by name in list-packages. (Bug#36981)
f96b8fd27c 2019-10-08 19:24:12 +0200
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=f96b8fd27c382a941c52c2938544b9b0e3a2fb0e

Here's the relevant etc/NEWS entry:

  *** New functions for filtering packages list.
  A new function has been added which allows users to filter the
  packages list by name: 'package-menu-filter-by-name'.  By default, it
  is bound to '/ n'.  Additionally, the function
  'package-menu-filter-by-keyword' has been renamed from
  'package-menu-filter'.  Its keybinding has also been changed to '/ k'
  (from 'f').  To clear any of the two filters, the user can now call
  the 'package-menu-clear-filter' function, bound to '/ /' by default.

> When I type "h", in the help popup "f" is reserved to mean
> "filter". Online documentation also mentions only "f" to filter the
> packages:
> https://www.gnu.org/software/emacs/manual/html_node/emacs/Package-Menu.html

The online manual has not yet been updated because Emacs 27 is still at
the pretest stage and not officially released.

> In describe-mode I see that filtering is done using "/" prefix key, not with "f".

Indeed.

The problem with 'h' (package-menu-quick-help) is that it is both
overengineered and limited in what it can do.  What it does is take a
word such as 'filter' and highlight a single character to indicate the
corresponding key binding.  E.g. ("filter" . 1) would highlight the 'i',
and "/-filter" would highlight the '/'.  This naively assumes that the
key binding is a single character, which is no longer the case.

On emacs-27, I propose we either remove the mention of filtering from
the quick help altogether, or write "/-filter" and let the user figure
out that '/' is actually a prefix that can be inspected in the usual
ways, such as by following it with C-h or <f1>.  For example: