[PATCH STABLE] util.datestr: do not crash on revisions with negative timestamp (issue2513)

[Adrian Buehlmann]

On 2010-11-23 14:28, Adrian Buehlmann wrote:
> # HG changeset patch
> # User Adrian Buehlmann <adrian at cadifra.com>
> # Date 1290514300 -3600
> # Branch stable
> # Node ID 9c16c05a8e0fec5d0449b2464b6a52ce9a6ce6d6
> # Parent  f08df4d38442bf641859f3de860ce0e5b6ba7763
> util.datestr: do not crash on revisions with negative timestamp (issue2513)
> 
> Python's time.gmtime(lt) fails on Windows, producing a traceback with
> 
>   ValueError: (22, 'Invalid argument')
> 
> if lt < -43200.
> 
> We get a local time boundary value of -43200 if we take "the epoch"
> 
>    Thu Jan 01 00:00:00 1970 = time.gmtime(0)
> 
> from timezone 'UTC+0' into timezone 'UTC-12'. All other timezones will have
> larger local time values for that point in time.
> 
> Aborting with a traceback on 'hg log' for revisions with a timestamp value
> < -43200 is clearly not acceptable.
> 
> Returning "invalid timestamp" or similar as string representation is not an
> option either, since that may crash other tools which parse the output of
> 'hg log'.
> 
> Instead, we teach util.datestr() to return the epoch in timezone UTC+0 on
> *all platforms*, represented by the string
> 
>   Thu Jan 01 00:00:00 1970 +0000
> 
> if the timestamp's unix time value is negative.
> 
> (based on a patch originally proposed by Benjamin Pollack)
> 
> diff --git a/mercurial/util.py b/mercurial/util.py
> --- a/mercurial/util.py
> +++ b/mercurial/util.py
> @@ -1026,6 +1026,9 @@ def datestr(date=None, format='%a %b %d 
>      number of seconds away from UTC. if timezone is false, do not
>      append time zone to string."""
>      t, tz = date or makedate()
> +    if t < 0:
> +        t = 0   # time.gmtime(lt) fails on Windows for lt < -43200
> +        tz = 0
>      if "%1" in format or "%2" in format:
>          sign = (tz > 0) and "-" or "+"
>          minutes = abs(tz) // 60

I intentionally left out patching util.strdate, because I think it
belongs into a separate, second patch. If you agree, we can discuss and
patch util.strdate in a separate iteration.