bug#30115: 25.1; cc-mode (C++) : bad indentation on function closing curly brackets

bug#30115: 25.1; cc-mode (C++) : bad indentation on function closing curly brackets

[Gaétan Allaert]

It is about an indentation issue in C++.

The closing curly bracket at the end of the function is wrongly indented
when:
1. at least one base_1 exists (the comma at the end of base_1 is
   required);
2. base_2 is the last call before the opening curly bracket of the
   function;
3. base_2 has only 1 argument that must be a symbol, not a literal or a
   string.

Example:
foo_good::foo_good (int arg_1, int arg_2) :
  base_1 (),
  base_2 (arg_1, arg_2) {
} // good indentation

foo_bad::foo_bad (int arg_1, int arg_2) :
  base_1 (),
  base_2 (arg_1) {
  } // bad identation

Thanks to have a look at this issue.



In GNU Emacs 25.1.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-09-15, modified by Debian built on trouble
Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
System Description:	Debian GNU/Linux 9.3 (stretch)

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
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 --with-sound=alsa --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
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 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
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NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
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  locale-coding-system: utf-8-unix

Major mode: C++/l

Minor modes in effect:
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Recent messages:
Mark set [2 times]
Replaced 2 occurrences
Saving file /home/allaert/bug.cpp...
Wrote /home/allaert/bug.cpp
(No changes need to be saved) [2 times]
Making completion list...
Quit
Mark set
Saving file /home/allaert/bug.cpp...
Wrote /home/allaert/bug.cpp
next-line: End of buffer

Load-path shadows:
/usr/share/emacs/25.1/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs25/site-lisp/cmake-data/cmake-mode hides /usr/share/emacs/site-lisp/cmake-mode
/usr/share/emacs/25.1/site-lisp/slime/lib/ert hides /usr/share/emacs/25.1/lisp/emacs-lisp/ert
/usr/share/emacs/25.1/site-lisp/slime/lib/ert-x hides /usr/share/emacs/25.1/lisp/emacs-lisp/ert-x

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Memory information:
((conses 16 231074 14250)
 (symbols 48 29159 1)
 (miscs 40 95 375)
 (strings 32 49655 7602)
 (string-bytes 1 1441279)
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bug#30115: 25.1; cc-mode (C++) : bad indentation on function closing curly brackets

[Alan Mackenzie]

Hello, Gaétam/

On Sun, Jan 14, 2018 at 23:13:23 +0000, Gaétan Allaert wrote:

> It is about an indentation issue in C++.

> The closing curly bracket at the end of the function is wrongly indented
> when:
> 1. at least one base_1 exists (the comma at the end of base_1 is
>    required);
> 2. base_2 is the last call before the opening curly bracket of the
>    function;
> 3. base_2 has only 1 argument that must be a symbol, not a literal or a
>    string.

> Example:
> foo_good::foo_good (int arg_1, int arg_2) :
>   base_1 (),
>   base_2 (arg_1, arg_2) {
> } // good indentation

> foo_bad::foo_bad (int arg_1, int arg_2) :
>   base_1 (),
>   base_2 (arg_1) {
>   } // bad identation

> Thanks to have a look at this issue.



> In GNU Emacs 25.1.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
>  of 2017-09-15, modified by Debian built on trouble
> Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
> System Description:	Debian GNU/Linux 9.3 (stretch)

[ .... ]

Thanks for taking the trouble to report this bug, and thanks even more
for cutting your example down to a concise, easy to work with snippet.
It seems already to be fixed in the emacs-26 branch, the fix being for
an entirely different symptom, but appears to fix this, too.

It will be some time before Emacs 26 gets released.  In the meantime,
can I ask you to apply the following patch to cc-engine.el in your Emacs
25.1 (in .../emacs/lisp/progmodes), compile it, and test it with your
real code.  (If you want any help applying the patch or compiling the
file, feel free to contact me by private mail.)  Would you please let me
know how well it solves the problem in your real code.  Thanks.



--- cc-engine.20180119.eeel	2017-10-01 17:14:49.185254672 +0000
+++ cc-engine.el	2018-01-19 17:49:09.308202347 +0000
@@ -7615,8 +7615,10 @@
 
 	 ;; CASE 11
 	 (when (and got-identifier
-		    (not context)
 		    (looking-at c-after-suffixed-type-decl-key)
+		    (or (eq context 'top)
+			(and (eq context nil)
+			     (match-beginning 1)))
 		    (if (and got-parens
 			     (not got-prefix)
 			     (not got-suffix)
@@ -8287,7 +8289,7 @@
 	       (c-forward-objc-directive)))
 
      (setq id-start
-	   (car-safe (c-forward-decl-or-cast-1 (c-point 'bosws) nil nil)))
+	   (car-safe (c-forward-decl-or-cast-1 (c-point 'bosws) 'top nil)))
      (< id-start beg)
 
      ;; There should not be a '=' or ',' between beg and the



-- 
Alan Mackenzie (Nuremberg, Germany).