[darcs-users] darcs patch: Add Patch-salt as ignored prefix
zooko at zooko.com
Wed Oct 8 13:25:49 UTC 2008
On Oct 8, 2008, at 7:14 AM, Eric Kow wrote:
> On Wed, Oct 08, 2008 at 07:03:49 -0600, zooko wrote:
>> There is a way to make this true: define an unambiguous encoding.
>> example: make it so that darcs always appends the following to the
>> end of
>> the patch comment: "Ignore-this-count-of-entries-to-ignore: 1".
> That's an interesting proposal, Zooko, but tricky to implement
> (especially with darcs being distributed and all), more so right
> up to the point of a release.
Hm, is it that tricky? There is a very simple part of it that we
could do for 2.1.0 since we you know that the count of entries to
ignore in darcs 2.1.0 is always exactly 2 (the patch salt and the
count of entries to ignore).
The implementation is simply to append the following string literal
to each patch comment: "Ignore-this-count-of-entries-to-ignore: 2",
and to hide any such line when displaying.
The reason to do it is because then future versions of darcs can be
more precise and safe about knowing what to ignore in a patch
comment, compared to if we do it the way currently proposed. If we
do it the way currently proposed, then future versions of darcs will
probably have to be a little more imprecise in hiding lines.
If this still seems like too big of a change (in terms of its effect
on future darcs's, rather than in terms of the source code required
to implement it), then at least let us try to be very limited in what
hidden fields darcs-2.1.0 will write into patch comments and what
things darcs-2.1.0 will hide from patch comments. For example, let
us require that the "Ignore-this-patch-salt: BLAHBLAHBLAH" field is
always the last line of the patch comment, and that it gets hidden
only if it is the last line and only if BLAHBLAHBLAH matches the
pattern of a a hex encoded random string of the right length.
The more constrained darcs 2.1.0 is in what it will do with regard to
adding stuff on write and with regard to hiding stuff on display the
more freedom future versions of darcs will have to do this better.
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