On Fri, Jul 18, 2014 at 8:30 PM, Warren Young <war...@etr-usa.com> wrote:
> "fossil help timeline" talks about a BASELINE. I've discovered by playing
> that it can be an artifact ID, but I assume there has to be more to it than
> that, else why use a different term?
>
> Neither the Schimpf book nor fossil help really explain the term. It
> doesn't appear on the documentation index page or in the FAQ.
A "baseline" is a side-effect of fossil's "delta manifests." Originally,
fossil required that all files belonging to a give version be included in
that checkin's manifest ("the official metadata"). That proved to be
problematic for repos with large numbers (thousands) of files, as it has to
record thousands of files in a list when only one changed. List member
Joerg Sonnenberg (spelling?) urged Richard to find a solution, and that
solution was "delta manifests." A baseline is a "normal" checkin record. A
delta manifest is a checkin record which records only files which changed
between its own version and the baseline version. Any given non-delta
checkin can be a baseline for arbitrary other delta manifests. If a delta
gets "too big," a new baseline checkin is created with all the files listed
in it, and further deltas can be generated from that one.
i've got a simple browser which might make this clearer:
http://fossil.wanderinghorse.net/repos/libfossil/cgidemo/index.cgi/manifest
see the Parent/Baseline links, click those, and note the UUIDs. Sometimes
the parent and baseline are the same, but not always. Typically any given
baseline stays a baseline of its successors until the list of file changes
gets to some computed portion of the original file list, at which point it
is considered to be "too far removed" from the current version and a new
baseline is created.
So, in short: a baseline manifest is simply a checkin record (i.e.
"manifest") which is _not_ a delta manifest. Whether or not it actually
acts as a baseline for any deltas is unimportant (maybe it does not now,
but will tomorrow).
> Can a tag name be a baseline?
>
No - only checkin records can. Originally, checkins were called manifests,
but the word manifest now has several meanings. See:
http://fossil.wanderinghorse.net/repos/libfossil/doxygen/page_terminology.html
i hope that makes some sort of sense.
--
----- stephan beal
http://wanderinghorse.net/home/stephan/
http://gplus.to/sgbeal
"Freedom is sloppy. But since tyranny's the only guaranteed byproduct of
those who insist on a perfect world, freedom will have to do." -- Bigby Wolf
_______________________________________________
fossil-users mailing list
fossil-users@lists.fossil-scm.org
http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
