[darcs-users] darcs patch: Add Patch-salt as ignored prefix

[zooko]

On Oct 8, 2008, at 7:50 AM, Nathan Gray wrote:

> On Wed, Oct 08, 2008 at 07:25:49AM -0600, zooko wrote:
>> 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.
>
> This starts to sound scary when the user could cause their
> 'Ignore-this' line to get absorbed instead of the
> 'Ignore-this-patch-salt', just by putting theirs at the end of the
> comment:
>
>   Ignore-this-count-of-entries-to-ignore: 2
>   Ignore-this-patch-salt: BLAHBLAHBLAH
>   Ignore-this-my-own-metadata: this messes up the ordering

This would only be possible if the user is able to edit the entire  
patch comment.  My proposal is that the user is not able to do so:  
they edit the patch comment in an editor, then they save it, then  
darcs appends "Ignore-this-patch-salt: BLAHBLAHBLAH" and "Ignore-this- 
count-of-entries-to-ignore: 2".

Therefore, if the last line of the patch comment as the user wrote it  
is this:

Ignore-this-my-own-metadata: note to self: remember to frobble the  
whatsits.  note to others: ignore this note.

Then after darcs processes the patch comment it will end with this:

Ignore-this-my-own-metadata: note to self: remember to frobble the  
whatsits.  note to others: ignore this note.
Ignore-this-patch-salt: BLAHBLAHBLAH
Ignore-this-count-of-entries-to-ignore: 2

Now when darcs >= 2.1.0 displays the patch comment, the display will  
come out to the user looking like this:

Ignore-this-my-own-metadata: note to self: remember to frobble the  
whatsits.  note to others: ignore this note.

See what I mean?  That's the key concept of "out-of-band  
signalling".  Make it so that the metadata which darcs adds and which  
darcs parses and hides and uses is completely separate from the patch  
comment that the user edits, and make it so the two cannot be  
confused with one another.

Regards,

Zooko
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