bug#9021: 24.0.50; epatch - weird, confusing, huh?

[Drew Adams]

emacs -Q
 
This is the first time I've tried to use `epatch'.
 
I have the file to patch (e.g. `toto.el') in one window,
and the patch (as a file, e.g. `throw.patch') in another.
Both files are in the same directory, which is also the current
directory (`default-directory').
 
`M-x epatch' in the buffer of the file to be patched.
 
`y' to "Is the patch already in a buffer?"
I entered the name of the buffer of the patch, `throw.patch'.
 
I entered the name of the file to patch, `toto.el', to the
question "File to patch (directory, if multifile patch):".
 
I got this message:
 
Ediff has inferred that
 c:/drews-lisp-20/replace.el
is assumed to be the target for this patch.  However, this file does not exist.
 
Please enter an alternative patch target ...
 
No idea what to do now.  Why does it "infer" a file named "replace.el",
when I input the name of the file to be patched, which has a totally
different name ("toto.el")?  Who said anything about "replace.el"?
 
Anyway, I again try to input the (same) name of the file to be patched:
"toto.el".
 
I then see this:
 
Ediff Session Group Panel: Multifile Patch
 

     Type ? to show useful commands in this buffer
 

*** Directory A: #<buffer throw.patch>
 
 
 
        Size   Last modified           Name
    ----------------------------------------------
 
    Session 1:
       112454   Jul  7 2011 08:24:00   c:/drews-lisp-20/toto.el
    Session 2:
       112454   Jul  7 2011 08:24:00   c:/drews-lisp-20/toto.el
 

Huh?  What does all of that mean?  Why does it think I want a
"Multifile Patch"?  Why does it (apparently) consider the patch buffer
to be a directory?  Why does it list two Sessions?  What do I do now?
 
I hit `?' for more info...and I understand...nothing more (maybe less).
 
I tried the same thing in Emacs 23.3 and 22.3, with the same result.  I
tried consulting the Ediff manual for `epatch', but it was no help here.
 
What am I missing?  I'll admit that I do not know what I'm doing, here,
but at the very least it seems like the UI is confusing and the doc is
not very helpful.
 
I have no idea where to begin, and all I'm trying to do is patch a
single file with a single patch.
 
OK, so eventually I realized (by accidentally mousing over text) that
I could click one of the two (why two? why identical?) "sessions".
I tried that and it applied the patch - bingo.  What to do then was
clear (I'm familiar with ediff).
 
Whether or not someone who understands `epatch' will consider any of
this a product bug (e.g. why "replace.el"?), I hope you will think
about it some more from a UI/user (esp. newbie) perspective.

I suggest that the `epatch' UI, doc, and help are a mess, at least for
an `epatch' newbie such as myself.  I hope that someone will improve
this, and I'd appreciate any explanation wrt the behavior I see and the
questions raised above.  I still have no clue what all of that is about.
Thx.
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2011-06-27 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.5) --no-opt --cflags
-Ic:/build/include'