C-x v u via *.~REV.~ reset file date to 1970-01-01

C-x v u via *.~REV.~ reset file date to 1970-01-01

[Simon Josefsson]

Visit a file in CVS and type a SPC and then remove it and save the
file. VC generate a backup file dated 1970-01-01:

jas@latte:~/src/libidn$ ls -la Makefile.am*
-rw-r--r--    1 jas      staff        1959 2003-08-26 04:22 Makefile.am
-rw-r--r--    1 jas      staff        1959 1970-01-01 01:00 Makefile.am.~1.91.~
jas@latte:~/src/libidn$ 

If you then do C-x v u, Emacs move the backup file back to the
original, but keeps the file date.  BSD make seem to use time=0 to
mean that the file doesn't exist, so you get an error that the file
doesn't exist, which is rather confusing.

For CVS, why not use the file date stored in CVS/Entries?  It would be
even better than using current time, which otherwise would be one
solution.

Re: C-x v u via *.~REV.~ reset file date to 1970-01-01

[Andre Spiegel]

On Tue, 2003-08-26 at 04:26, Simon Josefsson wrote:

> Visit a file in CVS and type a SPC and then remove it and save the
> file. VC generate a backup file dated 1970-01-01:
> 
> jas@latte:~/src/libidn$ ls -la Makefile.am*
> -rw-r--r--    1 jas      staff        1959 2003-08-26 04:22 Makefile.am
> -rw-r--r--    1 jas      staff        1959 1970-01-01 01:00 Makefile.am.~1.91.~
> jas@latte:~/src/libidn$ 

I see this on my system (Debian) too, but it's clearly an error.  VC
creates the backup file using copy-file with KEEP-TIME non-nil
(vc-hooks.el, line 594).  The doc string of copy-file does mention that
KEEP-TIME doesn't work on all systems, but I would assume GNU/Linux is
not one of them, and even if it doesn't work on a system, 1970-01-01 is
clearly not an acceptable date.

Something must be broken in copy-file, fileio.c.  Ken Raeburn's change
of 2002-07-15 (version 1.454) may be a candidate, since it's the last
time the keep-time stuff was changed, but I'm not knowledgable in this
area.  Could somebody else please have a look?