bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

[Tom Tromey]

I did "C-x v l" on a file with 5 revisions.
They all appear in *vc-change-log*.

At the bottom I see two buttons:

    Show 2X entries    Show unlimited entries

First, there aren't any more entries, so showing these buttons is
confusing.  That's somewhat understandable but it would be nice if it
didn't do that.

Clicking "Show 2X entries" shows the same data -- and the buttons
reappear.  In this case the buttons definitely should not show up.

Clicking "Show unlimited entries" does the right thing -- the buttons go
away.

This behavior is more confusing when the entries don't fit in the
window.  Then it isn't obvious if clicking the button actually got more
entries or not.





In GNU Emacs 25.0.50.3 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.9)
 of 2014-10-09 on pokyo
Repository revision: 118080 eggert@cs.ucla.edu-20141009065410-dhgjku4gclzl71kj
Windowing system distributor `Fedora Project', version 11.0.11404000
System Description:	Fedora release 20 (Heisenbug)

Configured using:
 `configure --prefix=/home/tromey/Emacs/install'

Configured features:
XPM JPEG TIFF GIF PNG SOUND GPM DBUS GSETTINGS NOTIFY ACL LIBSELINUX
GNUTLS LIBXML2 FREETYPE LIBOTF XFT ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: JS

Minor modes in effect:
  shell-dirtrack-mode: t
  erc-spelling-mode: t
  erc-truncate-mode: t
  diff-auto-refine-mode: t
  flyspell-mode: t
  which-function-mode: t
  projectile-global-mode: t
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  desktop-save-mode: t
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  erc-services-mode: t
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
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  erc-pcomplete-mode: t
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  erc-track-minor-mode: t
  erc-match-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-netsplit-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  savehist-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: do-auto-fill

Recent input:
C-a M-x r g r e p <return> J S O N <return> <return> 
<M-backspace> <return> C-x o C-x 1 <f9> <f9> <f9> <f9> 
<f9> <f9> <f9> <f9> <f9> <f9> <f9> C-x b s c r <tab> 
<return> C-x 1 C-u C-SPC <switch-frame> C-z n C-x b 
s h a r <tab> <return> C-u C-SPC C-u C-SPC C-p C-p 
C-e M-b M-b M-b M-b M-d e v e n t u a l l y SPC _ r 
e q u e s t M-q C-n C-x C-s C-g C-r _ r e q u e s t 
C-r C-r C-r C-r C-r C-r C-r C-r C-a C-u C-u C-n C-l 
C-z n C-u C-u C-p C-s a r e q u e s t C-s C-s C-s C-s 
C-r C-r C-a C-u C-u C-p C-s f r e q e <backspace> <backspace> 
<backspace> e e z e C-s C-a C-u C-n C-u C-n C-s _ s 
e n d C-w C-s C-s C-a C-u C-n C-u C-n C-l C-x b t r 
a n <tab> <return> C-x v g C-z n <f10> C-l C-l C-l 
<f10> <f10> <f10> <f10> <f10> C-z n C-e C-a d C-x 1 
C-s f r e e z e C-a C-c b C-c C-g C-x b <return> C-h 
c a a r d e e p C-s C-f C-f C-f C-g B M-v C-x k <return> 
y e s <return> C-z n <f10> <f10> y i k e s C-a C-k 
<f10> <f10> C-z n C-z n <switch-frame> <switch-frame> 
C-z n C-z n <f10> <f10> <f10> C-z n C-z n <f10> <f10> 
C-x v l C-x 1 M-> C-p C-n C-a <return> M-> <f10> <f10> 
M-> C-u C-b <return> M-> C-z n M-x r e p o r t - e 
m <tab> <return>

Recent messages:
Annotating... done
Error during redisplay: (jit-lock-function 1) signaled (wrong-type-argument arrayp nil)
r is undefined
Cannot extract revision number from the current line
e is undefined [2 times]
Annotating...
funcall-interactively: End of buffer [3 times]
Quit
B is undefined
scroll-down-command: Beginning of buffer

Load-path shadows:
/home/tromey/.emacs.d/elpa/css-mode-1.0/css-mode hides /home/tromey/Emacs/install/share/emacs/25.0.50/lisp/textmodes/css-mode
/home/tromey/.emacs.d/elpa/bubbles-0.5/bubbles hides /home/tromey/Emacs/install/share/emacs/25.0.50/lisp/play/bubbles
/home/tromey/Emacs/install/share/emacs/25.0.50/lisp/loaddefs hides /home/tromey/Emacs/install/share/emacs/25.0.50/lisp/obsolete/loaddefs

Features:
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find-dired ffap two-column autoconf autoconf-mode sh-script smie
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flow-fill gnus-html xml mm-url mailalias bbdb-sc supercite regi
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misearch multi-isearch erc-spelling erc-truncate bbdb-gui bbdb-hooks
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utf7 netrc nnoo parse-time gnus-spec gnus-int gnus-range gnus-win gnus
gnus-ems nnheader message rfc822 mml mml-sec mm-decode mm-bodies
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kmacro pkg-info find-func lisp-mnt epl grep compile dash s minimap
autorevert filenotify desktop frameset cus-start cus-load status
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tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak
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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 dbusbind gfilenotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)

Memory information:
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 (buffers 976 1690)
 (heap 1024 538033 100324))

Tom

bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

[Lars Ingebrigtsen]

Tom Tromey <tom@tromey.com> writes:

> I did "C-x v l" on a file with 5 revisions.
> They all appear in *vc-change-log*.
>
> At the bottom I see two buttons:
>
>     Show 2X entries    Show unlimited entries
>
> First, there aren't any more entries, so showing these buttons is
> confusing.  That's somewhat understandable but it would be nice if it
> didn't do that.

(I'm going through old bug reports that unfortunately got no response at
the time.)

It would be -- and this behaviour is still present in Emacs 28.  But I
guess the problem is that we don't really know how many revisions there
are?

On the other hand, we know how many revisions we asked for, and we know
how many we got.  So if we asked for 2000 revisions, and got 5
revisions, then displaying those buttons is probably not necessary?  And
that sounds like something that should be easy to implement.  (If we
asked for 2000 and got 2000, then we don't know, and we'll probably get
a bug report on that, too, but whatevs).

I've now done this on the trunk, and it seem to work OK in my repos.
More testing in non-git VCs would be nice.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

[Tom Tromey]

Lars> (If we
Lars> asked for 2000 and got 2000, then we don't know, and we'll probably get
Lars> a bug report on that, too, but whatevs).

One thing Emacs could do is, if 2000 are requested by the user, ask the
VCS for 2001.  Then it could always be accurate.

Tom

bug#18959: 25.0.50; vc-change-log displays "show 2x entries" even when none available

[Lars Ingebrigtsen]

Tom Tromey <tom@tromey.com> writes:

> One thing Emacs could do is, if 2000 are requested by the user, ask the
> VCS for 2001.  Then it could always be accurate.

That's true, but I'm not sure the VC backends are that accurate...

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no