Perforce: Find source changelist for a branch

Question

Short version:

After branching in P4, how can I find out the "source" changelist of the branch?

Long version:

Let's say I have a main branch of my project at

//project/main/...

The latest changelist submitted here is @123, when I decide to create a branch for release 1.0 in

//project/1.0/...

From P4V, a new changelist is created (say @130), resolved and submitted.

From the CLI, it would look something like this:

p4 integrate -c 123 -o //project/main/... //project/1.0/...
p4 submit

Later, I look at the changelists under //project/1.0, and see the @130 changelist containing a lot of branched files. How can I find out the changelist no. that this was originally branched from (that is, @123) ?

Answer 1

p4 changes will display a list of submitted changelists, optionally filtered to a specific path.

p4 changes //project/main/...
Change 123 ... 'Very last change.'
Change 122 ... 'Next-to-last change.'
Change 100 ... 'Only two changes to go...'
...

No surprise there, but, as you've found, p4 changes is less helpful when you integrate all those changes in a single change:

p4 changes //project/1.0/...
Change 130 ... 'Integrated everything from main.'

The trick is to use the -i option which includes any changelists integrated into the specified files.

p4 changes -i //project/1.0/...
Change 130 ... 'Integrated everything from main.'
Change 123 ... 'Very last change.'
Change 122 ... 'Next-to-last change.'
Change 100 ... 'Only two changes to go...'
...

To get exactly what you want (123) you'll need to write a script which filters the output from p4 changes -i //project/1.0/... to remove any change listed by p4 changes //project/1.0/... (and then take the most recent remaining change).

(When exploring, I frequently also find the -m max option useful. This limits changes to the 'max' most recent. This helps your output not flow offscreen when there are many changes.)

Answer 2

I don't know of any simple command that performs what you would like to do. If you are willing to script a little bit and the command doesn't have to execute fast you could perhaps try to script something like the following for all branched files:

1. Find the source file/revision for a target file.

   p4 filelog //project/1.1/foo.bar#1
   //project/1.1/foo.bar
   ... #1 change 6416 branch on 2009/07/10 by foo@bar (text) 'Release 1.1'
   ... ... branch from //project/main/foo.bar#1,#2

2. Get the change list at which the source file/revision was submitted.

   p4 fstat //project/main/foo.bar#2
   ... depotFile //project/main/foo.bar
   ... headAction edit
   ... headType text
   ... headTime 1201771167
   ... headRev 2
   ... headChange 5353
   ... headModTime 1201770971

3. Repeat for all files in branch and select the highest change no (headChange above), which should be the latest change submitted to the parent before branching for that specific file. You could get a complete listing of all branched files using e.g. "p4 files //project/1.0/...#1".

(or perhaps take the easy way out and ask Perforce support)