bug#23730: 24.5; format removes text properties

bug#23730: 24.5; format removes text properties

[ynyaaa]

`format' may remove text properties.
Second form is an example.

(format (propertize "%d" 'face '(:background "red")) 1)
=>#("1" 0 1 (face (:background "red")))

(format (propertize "%2d" 'face '(:background "red")) 1)
=>" 1"

(format (propertize "%02d" 'face '(:background "red")) 1)
=>#("01" 0 2 (face (:background "red")))




In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.0.6002
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'

Important settings:
  value of $LANG: JPN
  locale-coding-system: cp932

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:

Load-path shadows:
None found.

Features:
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easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
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japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
w32notify w32 multi-tty emacs)

Memory information:
((conses 8 76884 6016)
 (symbols 32 17447 0)
 (miscs 32 38 127)
 (strings 16 10667 4075)
 (string-bytes 1 268458)
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bug#23730: 24.5; format removes text properties

[Eli Zaretskii]

> From: ynyaaa@gmail.com
> Date: Wed, 08 Jun 2016 22:41:46 +0900
> 
> 
> `format' may remove text properties.
> Second form is an example.
> 
> (format (propertize "%d" 'face '(:background "red")) 1)
> =>#("1" 0 1 (face (:background "red")))
> 
> (format (propertize "%2d" 'face '(:background "red")) 1)
> =>" 1"
> 
> (format (propertize "%02d" 'face '(:background "red")) 1)
> =>#("01" 0 2 (face (:background "red")))

Why did you expect the properties of the format specifier to be
preserved?  The documentation only promises that the characters
_other_ than the format specifier are copied with their properties,
but makes no such promises about the specifier.

IOW, this is the intended behavior.  If you want the result of the
conversion to have some properties, you should propertize the return
value.

bug#23730: 24.5; format removes text properties

[ynyaaa]

Eli Zaretskii <eliz@gnu.org> writes:

>The documentation only promises that the characters
>_other_ than the format specifier are copied with their properties,

Text properties after the format spericifier are copied
with wrong positions.

(format (concat (propertize "%2d" 'x 'X)
                (propertize "a" 'a 'A)
                (propertize "b" 'b 'B))
        1)
=>#(" 1ab" 0 1 (a A) 1 2 (b B))

bug#23730: 24.5; format removes text properties

[Eli Zaretskii]

> From: ynyaaa@gmail.com
> Cc: 23730@debbugs.gnu.org
> Date: Thu, 09 Jun 2016 11:07:01 +0900
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >The documentation only promises that the characters
> >_other_ than the format specifier are copied with their properties,
> 
> Text properties after the format spericifier are copied
> with wrong positions.
> 
> (format (concat (propertize "%2d" 'x 'X)
>                 (propertize "a" 'a 'A)
>                 (propertize "b" 'b 'B))
>         1)
> =>#(" 1ab" 0 1 (a A) 1 2 (b B))

Fixed on the master branch, thanks.  Fixing this also corrected your
originally reported issue, so I made it clear in the documentation
that the text properties from the format specifiers are also copied.