git snapshots, PORTVERSION, PORTEPOCH

[Matthew D. Fuller]

On Sat, Feb 21, 2009 at 10:45:01AM +0200 I heard the voice of
Ion-Mihai Tetcu, and lo! it spake thus:
> 
> Since you have the date, you can easily get the git magic string.

Not necessarily true at all, in VCS's that don't limit to single-line
history.  Consider the case where I'm working on a feature in a
private branch since 2000-01-01.  You take a snapshot of the trunk
branch on 2000-02-01.  My branch is merged on 2000-03-01.

Now on 2000-04-01, somebody wants to look back and figure out which
revision corresponds to your timestamp.  There are at least 2 paths
through the history that could have a commit at [to any arbitrary
granularity] the exact same date/time; there could well be more, on an
active project.  Depending on the particular system and workflow, it
may not even be theoretically possible to figure out which is referred
to, short of doing full source comparisons; it can certainly be
non-trivial in many cases.


-- 
Matthew Fuller     (MF4839)   |  fullermd at over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.