[p4] What is a Shelf

Thu May 17 07:30:56 PDT 2007

Perhaps if your syncs take minutes to complete.  With a full workspace
(which is sometimes what is needed in our case to fix a bug) being about
40G+, that's not always a viable option.

________________________________

	From: Jeremy Russell [mailto:russell_jeremy at yahoo.com] 
	Sent: Thursday, May 17, 2007 8:59 AM
	To: Mark Allender; Rich Ireland; perforce-user at perforce.com
	Subject: Re: [p4] What is a Shelf

	The biggest reason I would use this is for code reviews and
moving changes around from branch to branch, without having to check in.
A dev calls says that I have a bug in my code, but they are over in some
obscure branch. I can fix the code were I am bundle it and give it to
them so that they can apply it there. This is nice in a set of branches
were initegrate velocity is very slow (a practive I highly recommend no
using).

	I could also use it to move some significant changes around from
one of my own client workspace to another one I own.

	Given the price on disk space, I think having multiple
workspaces is an adequate soltuion for the "I have a bug to fix"
scenario.

	-Jeremy

	Mark Allender <marka at volition-inc.com> wrote:

		One reason is that we might have a developer who has
half the source tree checked out (200+ files) in some major graphical
system rewrite. He needs to fix a big in the current system. Rather than
branch work in progress (or branch 200K + files), he can use our
equivalent of p4tar (called p4rchive), put the stuff on ice, fix the
bug, submit, and restore his archive. Archiving and restoring could
easily take on the order of seconds compared to long length of time of
doing a branch (not to mention the complexity if you wanted to branch in
progress).

		He could use another workspace, but then it would have
to be synced and that would take a long time too.

		________________________________

		From: perforce-user-bounces at perforce.com on behalf of
Rich Ireland
		Sent: Thu 5/17/2007 12:23 AM
		To: perforce-user at perforce.com
		Subject: Re: [p4] What is a Shelf

		Why all this talk about a 'shelf' when you can just have
a sandbox 
		branch already? It seems very odd to me to have a source
*control* 
		system and want to pass data *around* it. Branching and
merging is very 
		cheap, very easy, and well understood - what more do you
want? 

		Is this some sort of fear of checking in something that
might break a 
		build? Again, that's what sandbox branches are for. 

		Jeff Grills wrote: 
		> I'm not so sure that you want to store just the diff -
it may be worth 
		> storing both the original version and the modified
version so that you can 
		> find a common ancestor from which to apply the diffs
to the new tree. I'm 
		> certainly no expert on 3-way merging, but having just
the diff seems like it 
		> throws away a lot of useful information that could
help when applying the 
		> changes to a different source tree. 
		> 
		> I seem to remember when I was working on p4tar that
there wasn't a way that 
		> I could get all the revisions that were integrated in
order to correctly 
		> restore an integrate operation. The problem had
something to do with 
		> integrating specific revisions and not ranges, like if
you manually 
		> integrated #1, #3, #5, #7, then the server didn't
really indicate that in 
		> any meaningful way - I think it would show #1-#7,
which was wrong. This was 
		> several years ago, and my memory is terrible, so I've
probably gotten some 
		> of the details wrong. I also seem to remember contact
support about the 
		> issue and they couldn't find a solution for me either,
but I'm not 100% sure 
		> that actually happened. It wasn't that big of an issue
for me, so I might 
		> have just ignored the issue and moved on. p4tar does
have primitive support 
		> for integrations primarily for code testing on other
platforms than the one 
		> on which the integration was performed, but it just
converts the resultant 
		> integration operations into edits, adds, and deletes. 
		> 
		> j 
		> 
		> -----Original Message----- 
		> From: perforce-user-bounces at perforce.com 
		> [mailto:perforce-user-bounces at perforce.com] On Behalf
Of Jeremy Russell 
		> Sent: Wednesday, May 16, 2007 9:58 PM 
		> To: perforce-user at perforce.com 
		> Subject: Re: [p4] What is a Shelf 
		> 
		> 
		> Conceptually this should not be that hard to do. In
practice, perhaps it is. 
		> Get the changes: 
		> 
		> Get the revision of the file under edit/integrate. 
		> 
		> Diff the file agianst said revision and get a diff
report. p4 diff gets 
		> you this in a variety of format. Save the diff off
someplace useful. It is 
		> impotatnt to save the diff, and not the whole file
(unless it is a binary) 
		> so that the change can be applied to multiple branches
or different verisons 
		> of the file. 
		> 
		> Save all of the source diff in some kind of text based
container file. 
		> How to store binaries (text based, hex) or keep
binaries whole in a 
		> container? Suggestions? 
		> 
		> Add in revision and branch meta data, how the file was
being stored, 
		> type of change (add, edit, integrate), what else? 
		> 
		> Package it up into a change bundle. 
		> 
		> Unpack the bundle: 
		> 
		> Open the target file for edit/add/integrate - whatever
the metadata tells 
		> us to do. 
		> Apply diff. 
		> Resolve diff as needed. 
		> Over simplification, I know, but the basic idea is
there. 
		> 
		> -Jeremy 
		> 
		> David Cooper wrote: 
		> William thinks correctly. I perhaps shouldn't have
used the word "sync". 
		> The P4 sync concept did not exist on the system I was
using. For our main 
		> use, which was checking multi-platform builds, it was
sufficient just to get 
		> hold of the same set of changes and use them to check
all builds before 
		> committing. 
		> 
		> In this system, a client could "save" a changelist in
a "staging" area on 
		> the server, and other clients could pull those
changes, overwriting (and 
		> optionally saving) their copies of the files, so that
their 
		> previous state 
		> could be restored easily. Resolving was not an option.
The "save" option was 
		> also used as a backup facility for pending changes. 
		> 
		> - David 
		> 
		> Ivey, William wrote: 
		>>> -----Original Message----- 
		>>> From: perforce-user-bounces at perforce.com 
		>>> [mailto:perforce-user-bounces at perforce.com]On Behalf
Of 
		>>> steve at vance.com 
		>>> 
		>>> 
		>>> Syncing to a pending changelist won't give you the
open state of the 
		>>> workspace. It will actually only give you the state
of the submitted 
		>>> depot up to the time the changelist was created. Be
careful with 
		>>> that. It's not 
		>>> what it may appear. 
		>>> 
		>>> Steve 
		>>> 
		>> I think he's talking about a feature he'd like added
to Perforce 
		>> whereby you *can* sync to a pending changelist and
get the expected 
		>> results - copies of the files as they appear on the
other user's 
		>> machine. (Of course, it would only be a valid
snapshot at the time you 
		>> synced.) 
		>> 
		>> It probably wouldn't be too hard to implement the
transfer within 
		>> Perforce. The server would get the pending changelist
owner's client 
		>> to upload the files then pass them down to the client
that is syncing. 
		>> The trick would be making sense of the operation in
terms of more 
		>> persistent operations such as real syncs and edits. 
		>> 
		>> For one thing, it wouldn't be a real sync - it's not
aligning your 
		>> workspace with the contents of the repository so it
breaks the normal 
		>> correspondence between the two. It might be
reasonable to require that 
		>> the files be checked out for editing on both clients
since that is the 
		>> operation which assumes a difference between the
repository and 
		>> workspaces. (Of course, if you've checked it out for
editing and made 
		>> your own changes before syncing, then what? Does it
overwrite or does 
		>> it force you to resolve?) 
		>> 
		>> -Wm 
		>> 
		>> _______________________________________________ 
		>> perforce-user mailing list -
perforce-user at perforce.com 
		>>
http://maillist.perforce.com/mailman/listinfo/perforce-user 
		>> 
		>> 
		> 

		-- 
		Rich Ireland 
		mailto:r.ireland at computer.org 
		Embedded & Real Time Engineering 
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