1 GNU Emacs NEWS -- history of user-visible changes.
3 Copyright (C) 2017-2018 Free Software Foundation, Inc.
4 See the end of the file for license conditions.
6 Please send Emacs bug reports to bug-gnu-emacs@gnu.org.
7 If possible, use M-x report-emacs-bug.
9 This file is about changes in Emacs version 27.
11 See file HISTORY for a list of GNU Emacs versions and release dates.
12 See files NEWS.26, NEWS.25, ..., NEWS.18, and NEWS.1-17 for changes
13 in older Emacs versions.
15 You can narrow news to a specific version by calling 'view-emacs-news'
16 with a prefix argument or by typing C-u C-h C-n.
19 +++ indicates that all necessary documentation updates are complete.
20 (This means all relevant manuals in doc/ AND lisp doc-strings.)
21 --- means no change in the manuals is needed.
22 When you add a new item, use the appropriate mark if you are sure it applies,
25 * Installation Changes in Emacs 27.1
27 ** The new configure option '--with-json' adds support for JSON using
28 the Jansson library. It is on by default; use 'configure
29 --with-json=no' to build without Jansson support. The new JSON
30 functions 'json-serialize', 'json-insert', 'json-parse-string', and
31 'json-parse-buffer' are typically much faster than their Lisp
32 counterparts from json.el.
34 ** Emacs has been ported to the -fcheck-pointer-bounds option of GCC.
35 This causes Emacs to check bounds of some arrays addressed by its
36 internal pointers, which can be helpful when debugging the Emacs
37 interpreter or modules that it uses. If your platform supports it you
38 can enable it when configuring, e.g., './configure CFLAGS="-g3 -O2
39 -mmpx -fcheck-pointer-bounds"' on Intel MPX platforms.
41 ** Emacs now normally uses a C pointer type instead of a C integer
42 type to implement Lisp_Object, which is the fundamental machine word
43 type internal to the Emacs Lisp interpreter. This change aims to
44 catch typos and support -fcheck-pointer-bounds. The 'configure'
45 option --enable-check-lisp-object-type is therefore no longer as
46 useful and so is no longer enabled by default in developer builds,
47 to reduce differences between developer and production builds.
50 * Startup Changes in Emacs 27.1
53 ** Emacs can now be configured using an early init file.
54 The file is called 'early-init.el', in 'user-emacs-directory'. It is
55 loaded very early in the startup process: before graphical elements
56 such as the tool bar are initialized, and before the package manager
57 is initialized. The primary purpose is to allow customizing how the
58 package system is initialized given that initialization now happens
59 before loading the regular init file (see below).
62 ** Installed packages are now activated *before* loading the init file.
63 This is part of a change intended to eliminate the behavior of
64 package.el inserting a call to 'package-initialize' into the init
65 file, which was previously done when Emacs was started. As a result
66 of this change, it is no longer necessary to call 'package-initialize'
69 However, if your init file changes the values of 'package-load-list' or
70 'package-user-dir', or sets 'package-enable-at-startup' to nil then it won't
71 work right without some adjustment:
72 - you can move that code to the early init file (see above), so those settings
73 apply before Emacs tries to activate the packages.
74 - you can use the new 'package-quickstart` so activation of packages does not
75 need to pay attention to 'package-load-list' or 'package-user-dir' any more.
78 * Changes in Emacs 27.1
81 ** The new option 'tooltip-resize-echo-area' avoids truncating tooltip text
82 on GUI frames when tooltips are displayed in the echo area. Instead,
83 it resizes the echo area as needed to accommodate the full tool-tip
87 ** Show modeline tooltips only if the corresponding action applies.
88 Customize the option 'mode-line-default-help-echo' to restore the old
89 behavior where the tooltip text is also shown when the corresponding
90 action does not apply.
93 ** New hook 'server-after-make-frame-hook'.
94 This hook is a convenient place to perform initializations in daemon
95 mode which require GUI features to be available. One example is
96 restoration of the previous session using the desktop.el package: put
97 the call to 'desktop-read' in this hook, if you want the GUI settings
98 to be restored, or if desktop.el needs to interact with you during
99 restoration of the session.
102 ** New function 'logcount' calculates an integer's Hamming weight.
105 ** New function 'libxml-available-p'.
106 This function returns non-nil if libxml support is both compiled in
107 and available at run time. Lisp programs should use this function to
108 detect built-in libxml support, instead of testing for that
109 indirectly, e.g., by checking that functions like
110 'libxml-parse-html-region' return nil.
113 ** New function 'fill-polish-nobreak-p', to be used in 'fill-nobreak-predicate'.
114 It blocks line breaking after a one-letter word, also in the case when
115 this word is preceded by a non-space, but non-alphanumeric character.
118 ** The limit on repetitions in regexps has been raised to 2^16-1.
119 It was previously limited to 2^15-1. For example, the following
120 regular expression was previously invalid, but is now accepted:
125 * Editing Changes in Emacs 27.1
128 ** New isearch bindings.
129 'C-M-w' in isearch changed from isearch-del-char to the new function
130 isearch-yank-symbol-or-char. isearch-del-char is now bound to 'C-M-d'.
133 ** New variable 'x-wait-for-event-timeout'.
134 This controls how long Emacs will wait for updates to the graphical
135 state to take effect (making a frame visible, for example).
138 ** New user option 'electric-quote-replace-double'.
139 This option controls whether '"' is replaced in 'electric-quote-mode',
140 in addition to other quote characters. If non-nil, ASCII double-quote
141 characters that quote text "like this" are replaced by double
142 typographic quotes, “like this”, in text modes, and in comments in
146 ** 'write-abbrev-file' now includes special properties.
147 'write-abbrev-file' now writes special properties like ':case-fixed'
148 for abbrevs that have them.
151 * Changes in Specialized Modes and Packages in Emacs 27.1
154 *** The function 'browse-url-emacs' can now visit a URL in selected window.
155 It now treats the optional 2nd argument to mean that the URL should be
156 shown in the currently selected window.
159 *** New 'package-quickstart' feature
160 When 'package-quickstart' is non-nil, package.el precomputes a big autoloads
161 file so that activation of packages can be done much faster, which can speed up
162 your startup significantly.
163 It also causes variables like package-user-dir and package-load-list to be
164 consulted when 'package-quickstart-refresh' is run rather than at startup so
165 you don't need to set them in your early init file.
167 *** New function 'package-activate-all'.
170 *** The ecomplete sorting has changed to a decay-based algorithm.
171 This can be controlled by the new `ecomplete-sort-predicate' variable.
173 *** The 'ecompleterc' file is now placed in ~/.emacs.d/ecompleterc by default
174 Of course it will still find it if you have it in ~/.ecompleterc
177 *** The function 'gnus-score-find-favorite-words' has been renamed
178 from 'gnus-score-find-favourite-words'.
181 *** The functions 'hfy-color', 'hfy-color-vals' and
182 'hfy-fallback-color-values' and the variables 'hfy-fallback-color-map'
183 and 'hfy-rgb-txt-color-map' have been renamed from names that used
184 'colour' instead of 'color'.
187 Authentication mechanisms can be added via external packages, by
188 defining new cl-defmethod of smtpmail-try-auth-method.
191 *** Support Hebrew-style footnotes
192 *** Footnote text lines are now aligned.
193 Can be controlled via the new variable 'footnote-align-to-fn-text'.
198 *** A new command 'css-cycle-color-format' for cycling between color
199 formats (e.g. "black" => "#000000" => "rgb(0, 0, 0)") has been added,
205 *** The new user option 'dired-create-destination-dirs' controls whether
206 'dired-do-copy' and 'dired-rename-file' should create non-existent
207 directories in the destination.
212 *** Output format of 'C-h l' (view-lossage) has changed.
213 For convenience, 'view-lossage' now displays the last keystrokes
214 and commands in the same format as the edit buffer of
215 'edit-last-kbd-macro'. This makes it possible to copy the lines from
216 the buffer generated by 'view-lossage' to the "*Edit Macro*" buffer
217 created by 'edit-last-kbd-macro', and to save the macro by 'C-c C-c'.
222 *** New filter ibuffer-filter-by-process; bound to '/E'.
224 ** Search and Replace
226 *** 'search-exit-option' provides new options 'move' and 'shift-move'
227 to extend the search string by yanking text that ends at the new
228 position after moving point in the current buffer. 'shift-move'
229 extends the search string by motion commands while holding down
235 *** The runtime behavior of Edebug's instrumentation can be changed
236 using the new variables 'edebug-behavior-alist',
237 'edebug-after-instrumentation-function' and
238 'edebug-new-definition-function'. Edebug's behavior can be changed
239 globally or for individual definitions.
241 ** Enhanced xterm support
243 *** New variable 'xterm-set-window-title' controls whether Emacs sets
244 the XTerm window title. This feature is experimental and is disabled
251 *** rgrep, lgrep and zrgrep now hide part of the command line
252 that contains a list of ignored directories and files.
253 Clicking on the button with ellipsis unhides it.
254 The abbreviation can be disabled by the new option
255 'grep-find-abbreviate'. The new command
256 'grep-find-toggle-abbreviation' toggles it interactively.
261 *** New variable 'ert-quiet' allows to make ERT output in batch mode
262 less verbose by removing non-essential information.
265 *** Gamegrid now determines its default glyph size based on display
266 dimensions, instead of always using 16 pixels. As a result, Tetris,
267 Snake and Pong are more playable on HiDPI displays.
272 *** Completing filenames in the minibuffer via 'C-TAB' now uses the
273 styles as configured by the variable 'completion-styles'.
275 ** New macros 'thunk-let' and 'thunk-let*'.
276 These macros are analogue to 'let' and 'let*', but create bindings that
277 are evaluated lazily.
281 *** New customizable variable next-error-find-buffer-function
282 defines the logic of finding a next-error capable buffer.
283 It has an option to use a single such buffer on selected frame, or
284 by default use the last buffer that navigated to the current buffer.
289 *** Expansion of history event designators is disabled by default.
290 To restore the old behavior, use
292 (add-hook 'eshell-expand-input-functions
293 #'eshell-expand-history-references)
295 *** The function 'shell-uniquify-list' has been renamed from
296 'eshell-uniqify-list'.
298 *** The function eshell/kill is now able to handle signal switches.
299 Previously eshell/kill would fail if provided a kill signal to send to the
300 process. It now accepts signals specified either by name or by its number.
304 *** The function 'pcomplete-uniquify-list' has been renamed from
305 'pcomplete-uniqify-list'.
310 *** New connection method "owncloud", which allows to access OwnCloud
311 or NextCloud hosted files and directories.
314 ** The options.el library has been removed.
315 It was obsolete since Emacs 22.1, replaced by customize.
318 * New Modes and Packages in Emacs 27.1
321 ** Emacs can now visit files in archives as if they were directories.
322 This feature uses Tramp and works only on systems which support GVFS,
323 i.e. GNU/Linux, roughly spoken. See the chapter "(tramp) Archive file
324 names" in the Tramp manual for full documentation of these facilities.
327 * Incompatible Lisp Changes in Emacs 27.1
329 ** The FILENAME argument to 'file-name-base' is now mandatory and no
330 longer defaults to 'buffer-file-name'.
333 ** The function 'eldoc-message' now accepts a single argument.
334 Programs that called it with multiple arguments before should pass
335 them through 'format' first. Even that is discouraged: for ElDoc
336 support, you should set 'eldoc-documentation-function' instead of
337 calling 'eldoc-message' directly.
339 ** Old-style backquotes now generate an error. They have been
340 generating warnings for a decade. To interpret old-style backquotes
341 as new-style, bind the new variable 'force-new-style-backquotes' to t.
343 ** Defining a Common Lisp structure using 'cl-defstruct' or
344 'cl-struct-define' whose name clashes with a builtin type (e.g.,
345 'integer' or 'hash-table') now signals an error.
347 ** When formatting a floating-point number as an octal or hexadecimal
348 integer, Emacs now signals an error if the number is too large for the
349 implementation to format (Bug#30408).
352 ** Some functions and variables obsolete since Emacs 22 have been removed:
353 archive-mouse-extract, assoc-ignore-case, assoc-ignore-representation,
354 backward-text-line, blink-cursor, bookmark-exit-hooks,
355 comint-use-prompt-regexp-instead-of-fields, compilation-finish-function,
356 count-text-lines, cperl-vc-header-alist, custom-face-save-command,
357 cvs-display-full-path, cvs-fileinfo->full-path, delete-frame-hook,
358 derived-mode-class, describe-char-after, describe-project,
359 desktop-basefilename, desktop-buffer-handlers,
360 desktop-buffer-misc-functions, desktop-buffer-modes-to-save,
361 desktop-enable, desktop-load-default, dired-omit-files-p,
362 disabled-command-hook, dungeon-mode-map, electric-nroff-mode,
363 electric-nroff-newline, electric-perl-terminator, focus-frame,
364 forward-text-line, generic-define-mswindows-modes, generic-define-unix-modes,
365 generic-font-lock-defaults, goto-address-at-mouse,
366 highlight-changes-colours, ibuffer-elide-long-columns, ibuffer-hooks,
367 ibuffer-mode-hooks, icalendar-convert-diary-to-ical,
368 icalendar-extract-ical-from-buffer, imenu-always-use-completion-buffer-p,
369 ipconfig-program, ipconfig-program-options, isearch-lazy-highlight-cleanup,
370 isearch-lazy-highlight-cleanup, isearch-lazy-highlight-initial-delay,
371 isearch-lazy-highlight-interval, isearch-lazy-highlight-max-at-a-time,
372 iswitchb-use-fonts, latin1-char-displayable-p, mouse-wheel-click-button,
373 mouse-wheel-down-button, mouse-wheel-up-button, new-frame, pascal-outline,
374 process-kill-without-query, recentf-menu-append-commands-p,
375 rmail-pop-password, rmail-pop-password-required, savehist-load,
376 set-default-font, spam-list-of-processors,
377 speedbar-add-ignored-path-regexp, speedbar-buffers-line-path,
378 speedbar-buffers-line-path, speedbar-ignored-path-expressions,
379 speedbar-ignored-path-regexp, speedbar-line-path, speedbar-path-line,
380 timer-set-time-with-usecs, tooltip-gud-display, tooltip-gud-modes,
381 tooltip-gud-toggle-dereference, unfocus-frame, unload-hook-features-list,
382 update-autoloads-from-directories, vc-comment-ring, vc-comment-ring-index,
383 vc-comment-search-forward, vc-comment-search-reverse, vc-comment-to-change-log,
384 vc-diff-switches-list, vc-next-comment, vc-previous-comment, view-todo,
385 x-lost-selection-hooks, x-sent-selection-hooks
388 * Lisp Changes in Emacs 27.1
391 ** New function assoc-delete-all.
393 ** 'print-quoted' now defaults to t, so if you want to see
394 (quote x) instead of 'x you will have to bind it to nil where applicable.
396 ** To avoid confusion caused by "smart quotes", the reader signals an
397 error when reading Lisp symbols which begin with one of the following
398 quotation characters: ‘’‛“”‟〞"'. A symbol beginning with such a
399 character can be written by escaping the quotation character with a
400 backslash. For example:
402 (read "‘smart") => (invalid-read-syntax "strange quote" "‘")
403 (read "\\‘smart") == (intern "‘smart")
406 ** Omitting variables after '&optional' and '&rest' is now allowed.
407 For example (defun foo (&optional)) is no longer an error. This is
408 sometimes convenient when writing macros. See the ChangeLog entry
409 titled "Allow `&rest' or `&optional' without following variable" for a
410 full listing of which arglists are accepted across versions.
412 ** Internal parsing commands now use syntax-ppss and disregard
413 open-paren-in-column-0-is-defun-start. This affects mostly things like
414 forward-comment, scan-sexps, and forward-sexp when parsing backward.
415 The new variable 'comment-use-syntax-ppss' can be set to nil to recover the old
418 ** The `server-name' and `server-socket-dir' variables are set when a
419 socket has been pased to Emacs (Bug#24218).
422 ** The 'file-system-info' function is now available on all platforms.
423 instead of just Microsoft platforms. This fixes a 'get-free-disk-space'
424 bug on OS X 10.8 and later (Bug#28639).
427 ** The function 'get-free-disk-space' returns now a non-nil value for
428 remote systems, which support this check.
431 ** The function 'make-string' accepts an additional optional argument.
432 If the optional third argument is non-nil, 'make-string' will produce
433 a multibyte string even if its second argument is an ASCII character.
435 ** (format "%d" X) no longer mishandles a floating-point number X that
436 does not fit in a machine integer (Bug#30408).
438 ** New JSON parsing and serialization functions 'json-serialize',
439 'json-insert', 'json-parse-string', and 'json-parse-buffer'. These
440 are implemented in C using the Jansson library.
443 ** The new function `mailcap-file-name-to-mime-type' has been added.
444 It's a simple convenience function for looking up MIME types based on
445 file name extensions.
448 ** The new function 'read-answer' accepts either long or short answers
449 depending on the new customizable variable 'read-answer-short'.
451 ** The function 'load' now behaves correctly when loading modules.
452 Specifically, it puts the module name into 'load-history', prints
453 loading messages if requested, and protects against recursive loads.
456 * Changes in Emacs 27.1 on Non-Free Operating Systems
459 ** Battery status is now supported in all Cygwin builds.
460 Previously it was supported only in the Cygwin-w32 build.
462 ** Emacs now handles key combinations involving the macOS "command"
463 and "option" modifier keys more correctly.
465 ** The special handling of `frame-title-format' on NS where setting it
466 to `t' would enable the macOS proxy icon has been replaced with a
467 separate variable, `ns-use-proxy-icon'. `frame-title-format' will now
468 work as on other platforms.
471 ----------------------------------------------------------------------
472 This file is part of GNU Emacs.
474 GNU Emacs is free software: you can redistribute it and/or modify
475 it under the terms of the GNU General Public License as published by
476 the Free Software Foundation, either version 3 of the License, or
477 (at your option) any later version.
479 GNU Emacs is distributed in the hope that it will be useful,
480 but WITHOUT ANY WARRANTY; without even the implied warranty of
481 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
482 GNU General Public License for more details.
484 You should have received a copy of the GNU General Public License
485 along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
491 paragraph-separate: "[
\f]*$"