Phabricator guidance

[Simon Peyton Jones]

Aha, that helps.  And looking further at https://phabricator.haskell.org/D202, I can see under "Revision update history" that there are four diffs all stashed in this on Phab ticket. (That contradicts my previous model which was one patch per Phab ticket; people have been complaining about that.)

So my new questions are:

* How can I apply "Diff 1" or "Diff 2"?  Using "arc patch" only applies "Diff 4"

* How can I apply all of "Diff 1" ... "Diff 4" in one go?

Simon

|  -----Original Message-----
|  From: Herbert Valerio Riedel [mailto:hvriedel at gmail.com]
|  Sent: 07 October 2014 10:05
|  To: Simon Peyton Jones
|  Cc: ghc-devs at haskell.org
|  Subject: Re: Phabricator guidance
|  
|  On 2014-10-07 at 10:57:00 +0200, Simon Peyton Jones wrote:
|  > I suppose I will have to look at this. But I have no clue how to do
|  so.
|  >
|  > D202 itself seems to be a very small patch (only ten lines or so),
|  so presumably it applies on top of some other patch?  But what?
|  >
|  > Someone said I could use
|  > 	arc patch D202
|  > to apply the patch in my own tree, which is crucial for reproducing
|  > the error that Jan is stuck on.
|  
|  > BUT the patch presumably applies to a
|  > particular commit, NOT the head of my current tree.  But what is the
|  > base commit to which it applies?  Does arc patch check out the base
|  > commit before applying?
|  
|  If you actually perform 'arc patch D202', this is the output you
|  currently get:
|  
|  
|  ,----
|  | Created and checked out branch arcpatch-D202.
|  |
|  |
|  |     This diff is against commit
|  3e17822f5f4e4d2f582dc0a053f532125f9777c7, but
|  |     the commit is nowhere in the working copy. Try to apply it
|  against the
|  |     current working copy state?
|  (3549c952b535803270872adaf87262f2df0295a4)
|  |     [Y/n] n
|  `----
|  
|  So yes, 'arc' tries apply the code-revision on top of the commit is
|  was based on; and in this case, it is actually missing from ghc.git :-
|  /
|  
|  What's more, you can also declare that a code-revisions builds on top
|  of another code-revision, in which case 'arc' will automatically try
|  to
|  (recursively) apply that other code-revision to your source-tree
|  first, before applying the one you are actually requesting on top.
|  
|  
|  I hope Austin or someone else may chime in to provide further
|  assistance if this doesn't help...