Date: Tue, 07 Aug 2001 09:36:01 -0700 (PDT) From: John Baldwin <jhb@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: current@FreeBSD.org Subject: p4 diff notes.. Message-ID: <XFMail.010807093601.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0108062051500.66925-100000@InterJet.elischer.org>
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On 07-Aug-01 Julian Elischer wrote:
>
> I have pushed the thread pointers down through most of the code
> though there are still many many places that assume that there is only one
> thread per process. (no multithreading yet, but getting closer..)
>
> At this stage diffs must be pushing close to 1MB (maybe more)
> (I don't know as I don't know yet how to get p4 to generate diffs :-)
It's not too hard. I have the smpng and jhb_preemption batches updating
diff's on freefall via cron. :)
To do a diff of files against files you have checked out, you use 'p4 diff'
such as 'p4 diff -du ...' to get a unified diff. Unfortunately, p4's diff
format isn't too patch friendly. There is also a 'p4 diff2' which does a
diff of files in the depot. p4 diff2 has an undocumented (well, it's
documented in 'p4 help undoc') option -u that will produce a unified diff that
patch can grok (albeit, it has the full depot path, so you'll have to use -p6
or some such to apply it). If you had a julian_kse branch off of the kse
branch you would use 'p4 diff2 -u -b julian_kse' to get a diff of the entire
branch. You can use 'p4 diff2 -u -b kse' to get a diff of the kse branch
against the head, but unfortunately it does a diff against the head of the
-current vendor import rather than against the latest files you last integrated
from.
To make the diff relative to when you last branched, you can use a revision
specification to refer to the state of the -current tree when you last did your
integrate. To do this, look up the change number of your last integrate from
-current, (right now 448 was your last MFC for example). You then generate a
diff between -current as of that change number and the head revision of your
branch (see 'p4 help revisions' or the revisions section of the quickstart
guide) like so:
> p4 diff2 -u -b kse @448 #head
However, having to look up the change number for diff's is a minor pain, and
makes it harder to automate things (like generating diff's in crontabs).
What you can do is create a label that tracks -current and is the last
branch point. First, you want to create a label whose View is the same as the
files your branch branches from. For example:
> p4 branch -o smpng
...
Branch: smpng
...
View:
//depot/vendor/freebsd/sys/... //depot/projects/smpng/sys/...
> p4 label -o smpng_base
Label: smpng_base
...
Description:
Label that tracks the smpng branch's 'base', i.e. the last
change imported from the FreeBSD current branch.
...
View:
//depot/vendor/freebsd/sys/...
You use 'p4 label' to create a label (set its View, description, etc.) You use
'p4 labelsync' to actually determine what revisions of what files the label
applies to. If you created a kse_base label, then you would start off by
specifying it as the last change you integrated from (448) like so:
> p4 labelsync -l kse_base @448
You can then do diff's like so:
> p4 diff2 -u -b kse @kse_base #head
Keeping the label up to date is fairly easy. When you want to do an integrate,
simply follow these steps:
> p4 labelsync -l kse_base #head
> p4 integrate -b kse @kse_base
> p4 resolve -a
> p4 resolve
> p4 submit
Note that you can update the label of individual files as well if you wish.
For example, my last integrate into smpng just brought across a commit to
sys/i386/isa/ipl.s rather than updating the entire tree:
> p4 integrate -b smpng sys/i386/isa/ipl.s
> p4 resolve -a
> p4 submit
I then updated the label on just that file like so:
> p4 labelsync -l smpng_base //depot/vendor/freebsd/sys/i386/isa/ipl.s#head
I usually keep my work trees off of the smpng branch up to date with the smpng
branch, so I don't have to bother with label's on those. This allows you to
get things working on a stable snapshot of current, and later do an integrate
to catch up.
Note that you could of done the MFC of one file as so:
> p4 labelsync -l smpng_base //depot/vendor/freebsd/sys/i386/isa/ipl.s#head
> p4 integrate -b smpng @smpng_base
> p4 resolve -a
> p4 submit
HTH.
--
John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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