bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

[Ed Avis]

Visit a file in a git or svn checkout.  Unknown to emacs, delete that
file.  Then do vc-revert to get back the original contents from version
control.

When vc-mode is used with a Subversion working copy, reverting a file
which has vanished on disk (but where the buffer is not marked as
modified) will just get a fresh copy and put it in the buffer.  That is
perhaps not ideal because it loses local changes.

When vc-mode is used with git, on reverting a file which no longer exists
on disk (where the buffer is not marked as modified), a diff is shown between the
empty file and the current contents in version control.  That is not a
particularly helpful diff to show the user.

If the file no longer exists on disk, then I suggest vc-revert
should act as follows:

- If the buffer is marked as modified, offer to save it, and after
  saving show diffs and prompt to revert as usual.

- If the buffer is not marked as modified, a diff should still be shown
  between the current buffer contents and what would be fetched from the
  version control system to replace it.  If that diff is empty, then
  just go ahead and revert.

Or alternatively, vc-revert should just automatically save-buffer first
if the underlying file no longer exists on disk.




In GNU Emacs 24.4.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.10.9)
 of 2014-11-03 on wcl-linux04.wcl.local
Configured using:
 `configure --build=x86_64-redhat-linux-gnu
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 --with-gpm=no build_alias=x86_64-redhat-linux-gnu
 host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
 -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
 -fstack-protector-strong --param=ssp-buffer-size=4
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Important settings:
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  value of $LC_CTYPE: en_GB.UTF-8
  value of $LC_MESSAGES: en_GB.UTF-8
  value of $LC_MONETARY: en_GB.UTF-8
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  value of $LC_TIME: en_GB.UTF-8
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  locale-coding-system: utf-8-unix

Major mode: nXML

Minor modes in effect:
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Recent input:
e e C-n C-n C-p C-x e e C-n C-n C-p C-x e e e C-n C-x 
e C-n C-x e e e C-n C-n C-n C-n C-x e C-x v u y e s 
DEL DEL y e s RET C-f C-f C-f C-f C-f C-f C-f C-f C-f 
C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f C-f 
C-f C-f C-f C-f C-d C-d C-d C-d C-d C-d C-d C-d C-d 
C-d C-a C-x C-s C-x v = C-x v v ESC p DEL DEL DEL DEL 
N Z . C-c C-c C-x o C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
C-x e e e e C-n C-x e e e C-n C-n C-n C-p C-x e e C-n 
C-n C-x e e C-n C-x e e C-n C-x e e e C-n C-x e C-n 
C-x e e e C-n C-n C-n C-n C-x e C-n C-x e C-n C-x e 
C-n C-x e e e e e e e e C-a C-x C-s ESC ! ESC p RET 
C-x o q ESC < C-s m s c i l o c a l C-a ESC ! m v SPC 
b u TAB . TAB DEL b u TAB DEL . i n _ p r o g r e s 
s SPC v DEL - v i RET C-x v u C-g ESC x e w p DEL DEL 
DEL r e p C-g C-h k C-x v u C-x o C-x o ESC x r e DEL 
DEL e DEL r e p o r t SPC e m SPC a DEL b SPC RET

Recent messages:
(Type e to repeat macro) [26 times]
Saving file /home/eda/git_working/repos/wwwroot/WaniSystems/Configuration/MarketSampler/jobs/build.trend.signals.xml...
Wrote /home/eda/git_working/repos/wwwroot/WaniSystems/Configuration/MarketSampler/jobs/build.trend.signals.xml
(Shell command succeeded with no output)
Mark set
Mark saved where search started
'build.trend.signals.xml' -> 'build.trend.signals.xml.in_progress'
Finding changes in /home/eda/git_working/repos/wwwroot/WaniSystems/Configuration/MarketSampler/jobs/build.trend.signals.xml...
Quit [2 times]
Type C-x 1 to delete the help window.

Load-path shadows:
None found.

Features:
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message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode
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Memory information:
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-- 
Ed Avis <eda@waniasset.com>
Please ignore autogenerated disclaimer below this line.

This email is intended only for the person to whom it is addressed and may contain confidential information. Any retransmission, copying, disclosure or other use of, this information by persons other than the intended recipient is prohibited. If you received this email in error, please contact the sender and delete the material. This email is for information only and is not intended as an offer or solicitation for the purchase or sale of any financial instrument. Wadhwani Asset Management LLP is a Limited Liability Partnership registered in England (OC303168) with registered office at 40 Berkeley Square, 3rd Floor, London, W1J 5AL. It is authorised and regulated by the Financial Conduct Authority.

bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

[Dmitry Gutov]

On 05/12/2015 06:13 PM, Ed Avis wrote:

> If the file no longer exists on disk, then I suggest vc-revert
> should act as follows:
>
> - If the buffer is marked as modified, offer to save it, and after
>    saving show diffs and prompt to revert as usual.

I believe we already do that. And if the user says no, the whole 
operation is aborted.

> - If the buffer is not marked as modified, a diff should still be shown
>    between the current buffer contents and what would be fetched from the
>    version control system to replace it.

That sounds a bit inconvenient to implement, and I guess I don't see a 
lot of benefit.

>  If that diff is empty, then
>    just go ahead and revert.

That goes against the main use case of vc-revert, as I see it: 
discarding uncommitted changes if you no longer want them.

> Or alternatively, vc-revert should just automatically save-buffer first
> if the underlying file no longer exists on disk.

That's doable. But then we'll also need to delete it afterwards if the 
user says no.

bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

[Ed Avis]

Thanks for looking into this bug.  I don't have a strong view on what the best behaviour would be, as long as it is *something* reasonable, and not just printing a diff of the contents against the empty file.
Having vc-revert save the buffer first if the file doesn't exist looks like a simple fix.

-- 
Ed Avis <eda@waniasset.com>
Please ignore autogenerated disclaimer below this point.

This email is intended only for the person to whom it is addressed and may contain confidential information. Any retransmission, copying, disclosure or other use of, this information by persons other than the intended recipient is prohibited. If you received this email in error, please contact the sender and delete the material. This email is for information only and is not intended as an offer or solicitation for the purchase or sale of any financial instrument. Wadhwani Asset Management LLP is a Limited Liability Partnership registered in England (OC303168) with registered office at 40 Berkeley Square, 3rd Floor, London, W1J 5AL. It is authorised and regulated by the Financial Conduct Authority.

bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

[Dmitry Gutov]

Version: 25.1

On 11/25/2015 05:38 PM, Ed Avis wrote:

> Having vc-revert save the buffer first if the file doesn't exist looks like a simple fix.

All right, we now do something like that. Thanks for the suggestion.

bug#20558: 24.4; vc-revert on deleted file (git and svn should be more consistent)

[Marcin Borkowski]

On 2015-11-26, at 16:16, Dmitry Gutov <dgutov@yandex.ru> wrote:

> Version: 25.1
>
> On 11/25/2015 05:38 PM, Ed Avis wrote:
>
>> Having vc-revert save the buffer first if the file doesn't exist looks like a simple fix.
>
> All right, we now do something like that. Thanks for the suggestion.

Hi,

does that mean that this bug can be closed?

-- 
Marcin