[bug #22710] cvs 1.11.22 ignoring symlink modification time - appears unintentional

[Nelson B Bolyard]

URL:
  <http://savannah.nongnu.org/bugs/?22710>

                 Summary: cvs 1.11.22 ignoring symlink modification time -
appears unintentional
                 Project: Concurrent Versions System
            Submitted by: nelsonb
            Submitted on: Monday 03/24/2008 at 00:37
                Category: Bug Fix (patch attached)
                Severity: 3 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 
           Fixed Release: None
   Fixed Feature Release: None

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Details:

In the cvs 1.11.22 sources, file src/vers_ts.c, function time_stamp(), there
is a block comment that appears to document how the function is intended to
work.  It says:

     /* If it's a symlink, return whichever is the newest mtime of
        the link and its target, for safety.
     */

And there is code that does both an lstat and a stat, and computes the lesser
of the two modification times, e.g. 

    struct stat sb;
    time_t mtime = 0L;
    if (!CVS_LSTAT (file, &sb))
    {
       mtime = sb.st_mtime;
    }
    if (!CVS_STAT (file, &sb))
    {
        if (mtime < sb.st_mtime)
           mtime = sb.st_mtime;
    }

But the value of this computed mtime is not used in the 
subsequent computations.  Instead, the value of sb.st_mtime 
is subsequently used.  

        tm_p = gmtime (&sb.st_mtime);
        cp = tm_p ? asctime (tm_p) : ctime (&sb.st_mtime);

This means that the comparison of the two mtimes is not used.
The actual behavior is to use the value left in the stat buf
after stat() returns.  Most of the time, this will be the 
value returned by stat.  The only way that sb.st_mtime can be 
the value from lstat is if lstat succeeds but stat fails.  

This tiny patch makes the code work the way that the comment
says it was intended to work.  

-       tm_p = gmtime (&sb.st_mtime);
-       cp = tm_p ? asctime (tm_p) : ctime (&sb.st_mtime);
+       tm_p = gmtime (&mtime);
+       cp = tm_p ? asctime (tm_p) : ctime (&mtime);

However, it's not entirely clear to me which is the more 
desirable behavior: the way the code actually works now, 
or the way that the comments say it was intended to work.




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