GNU Emacs NEWS -- history of user-visible changes.

Copyright (C) 2017-2020 Free Software Foundation, Inc.
See the end of the file for license conditions.

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If possible, use 'M-x report-emacs-bug'.

This file is about changes in Emacs version 28.

See file HISTORY for a list of GNU Emacs versions and release dates.
See files NEWS.27, NEWS.26, ..., NEWS.18, and NEWS.1-17 for changes
in older Emacs versions.

You can narrow news to a specific version by calling 'view-emacs-news'
with a prefix argument or by typing 'C-u C-h C-n'.

Temporary note:
+++ indicates that all relevant manuals in doc/ have been updated.
--- means no change in the manuals is needed.
When you add a new item, use the appropriate mark if you are sure it
applies, and please also update docstrings as needed.


* Installation Changes in Emacs 28.1

** Cairo graphics library is now used by default if found.
'--with-cairo' is now the default, if the appropriate development files
are found by 'configure'.  Note that building with Cairo means using
Pango instead of libXFT for font support.  Since Pango 1.44 has
removed support for bitmapped fonts, this may require you to adjust
your font settings.

Note also that 'FontBackend' settings in ".Xdefaults" or
".Xresources", or 'font-backend' frame parameter settings in your init
files, may need to be adjusted, as 'xft' is no longer a valid backend
when using Cairo.  Use 'ftcrhb' if your Emacs was built with HarfBuzz
text shaping support, and 'ftcr' otherwise.  You can determine this by
checking 'system-configuration-features'.  The 'ftcr' backend will
still be available when HarfBuzz is supported, but will not be used by
default.  We strongly recommend building with HarBuzz support. 'x' is
still a valid backend.

---
** 'configure' now warns about building with libXft support.
libXft is unmaintained, and causes a number of problems with modern
fonts including but not limited to crashes; support for it may be
removed in a future version of Emacs.  Please consider using
Cairo + HarfBuzz instead.

---
** 'configure' now warns about not using HarfBuzz if using Cairo.
We want to encourage people to use the most modern font features
available, and this is the Cairo graphics library + HarfBuzz for font
shaping, so 'configure' now recommends that combination.

---
** The ftx font backend driver has been removed.
It was declared obsolete in Emacs 27.1.


* Startup Changes in Emacs 28.1


* Changes in Emacs 28.1

** Support for '(box . SIZE)' cursor-type.
By default, 'box' cursor always has a filled box shape.  But if you
specify cursor-type to be '(box . SIZE)', the cursor becomes a hollow
box if the point is on an image larger than 'SIZE' pixels in any
dimension.


* Editing Changes in Emacs 28.1

+++
** New command 'undo-redo'

+++
** 'read-number' now has its own history variable.
Additionally, the function now accepts a HIST argument which can be
used to specify a custom history variable.

+++
** Input history for 'goto-line' is now local to every buffer.
Each buffer will keep a separate history of line numbers used with
'goto-line'.  This should help making faster the process of finding
line numbers that were previously jumped to.

+++
** When 'suggest-key-bindings' is non-nil, the completion list of 'M-x'
shows equivalent key bindings for all commands that have them.


* Changes in Specialized Modes and Packages in Emacs 28.1

** Help

+++
*** New command 'describe-keymap' describes keybindings in a keymap.

---
** The old non-SMIE indentation of 'sh-mode' has been removed.

---
** The sb-image.el library is now marked obsolete.
This file was a compatibility kludge which is no longer needed.

---
** 'lisp-mode' now uses 'common-lisp-indent-function'.
To revert to the previous behaviour,
'(setq lisp-indent-function 'lisp-indent-function)' from 'lisp-mode-hook'.

** Edebug

+++
*** Edebug specification lists can use the new keyword '&error', which
unconditionally aborts the current edebug instrumentation with the
supplied error message.

** Tramp

+++
*** New connection method "media", which allows accessing media devices
like cell phones, tablets or cameras.

** map.el

*** Pcase 'map' pattern added keyword symbols abbreviation.
A pattern like '(map :sym)' binds the map's value for ':sym' to 'sym',
equivalent to '(map (:sym sym))'.
** Package

+++
*** New functions to filter the package list.
The filter command key bindings are as follows:

key             binding
---             -------
/ a             package-menu-filter-by-archive
/ k             package-menu-filter-by-keyword
/ n             package-menu-filter-by-name
/ s             package-menu-filter-by-status
/ v             package-menu-filter-by-version
/ /             package-menu-filter-clear


* New Modes and Packages in Emacs 28.1


* Incompatible Lisp Changes in Emacs 28.1

** 'equal' no longer examines some contents of window configurations.
Instead, it considers window configurations to be equal only if they
are 'eq'.  To compare contents, use 'compare-window-configurations'
instead.  This change helps fix a bug in 'sxhash-equal', which returned
incorrect hashes for window configurations and some other objects.

---
** The obsolete function 'thread-alive-p' has been removed.

** 'dns-query' now consistently uses Lisp integers to represent integers.
Formerly it made an exception for integer components of SOA records,
because SOA serial numbers can exceed fixnum ranges on 32-bit platforms.
Emacs now supports bignums so this old glitch is no longer needed.

** The Lisp variables 'previous-system-messages-locale' and
'previous-system-time-locale' have been removed, as they were created
by mistake and were not useful to Lisp code.


* Lisp Changes in Emacs 28.1

** The module header 'emacs-module.h' now contains type aliases
'emacs_function' and 'emacs_finalizer' for module functions and
finalizers, respectively.

** Module functions can now install an optional finalizer that is
called when the function object is garbage-collected.  Use
'set_function_finalizer' to set the finalizer and
'get_function_finalizer' to retrieve it.

** 'parse-time-string' can now parse ISO 8601 format strings,
such as "2020-01-15T16:12:21-08:00".


* Changes in Emacs 28.1 on Non-Free Operating Systems

+++
** On macOS, Emacs can now load dynamic modules with a ".dylib" suffix.
'module-file-suffix' now has the value ".dylib" on macOS, but the
".so" suffix is supported as well.


----------------------------------------------------------------------
This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.


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