[p4] Diffing renamed files before submitting

[Alen Ladavac]

A curious problem came up by one of my colleagues and I was certain
that p4 could handle that nicely even in p4win, but even resolving to
manual command line option wizardry didn't help.

The scenario is:

1) open a file for rename, which turns out as a delete and an add
(branch)
2) reopen it for edit (because you need to change the #include
filenames in it, if you are to submit e.g. .h and .cpp both renamed in
one go.)
3) now try to check the diffs you did in this edit.

It is weird that once you submit this, the history is very easy to
access and the diffs work normally, but we'd like to see the diffs
before submition - to be sure what was done. Somehow seems that there
is no way to force p4 to compare one file in depot with another file
on client. The only way around it we've found was to use another
client to sync the deleted file and manually compare two files on the
disk using BeyondCompare.

Is there something we are missing here? Is there some reason why this
should be so complicated?

Thanks,
Alen