[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

Re: svn commit: r996581 - in /subversion/trunk/subversion: libsvn_diff/parse-diff.c tests/cmdline/patch_tests.py

From: Daniel Shahaf <d.s_at_daniel.shahaf.name>
Date: Fri, 17 Sep 2010 01:42:09 +0200

Stefan Sperling wrote on Wed, Sep 15, 2010 at 21:40:16 +0200:
> On Wed, Sep 15, 2010 at 06:15:58PM +0200, Daniel Shahaf wrote:
> > Stefan Sperling wrote on Tue, Sep 14, 2010 at 21:18:26 +0200:
> > > On Tue, Sep 14, 2010 at 12:49:06PM +0100, Julian Foad wrote:
> > > > Right. The issue seems to be "How do I determine what path I should
> > > > apply the patch to?" If the patch style is
> > > >
> > > > --- wc/file
> > > > +++ wc/file
> > > >
> > > > or
> > > >
> > > > --- old_wc/file
> > > > +++ new_wc/file
> > > >
> > > > then you're going to be stripping the first component so it doesn't
> > > > matter which path you use. If the patch is just to one file and looks
> > > > something like
> > > >
> > > > --- wc/file.old
> > > > +++ wc/file
> > > >
> > > > or
> > > >
> > > > --- wc/file
> > > > +++ wc/file.new
> > > >
> > > > or
> > > >
> > > > --- wc/file.old
> > > > +++ wc/file.new
> > > >
> > > > then obviously it's not so simple and the patch consumer (person) may
> > > > need to be able to tell "svn patch" which path it should look at if
> > > > we're to be able to handle cases like this.
> > >
> > > Yes. I've been trying to come up with a good UI for selecting the right
> > > filename for svn patch to use. Any ideas?
> >
> > Paraphrasing my commit reply a few hours ago, how about:
> >
> > * Always use the name from the /^+++/ line by default (regardless of --rd).
> > * Have a --strip-extension flag. (Effect: filename loses everything after the last dot)
> > * Have a the following config option:
> > [[[
> > # ~/.subversion/config
> > [miscellany]
> > patch-strip-extensions = .new .old .orig .org ~ \
> > .merge-left .merge-right .working
> > ]]]
> > for extensions that are stripped automagically.
> >
> > Sounds sane? (I haven't thought about this /too/ much, so beware of
> > bugs in the above idea)
>
> Looking at the patch(1) man page, it sounds like we don't really need
> to reinvent the wheel here:
>
> patch will choose the file name by performing the following steps, with
> the first match used:
>
> 1. If patch is operating in strict IEEE Std 1003.1-2008 (``POSIX'')
> mode, the first of the ``old'', ``new'' and ``index'' file names
> that exist is used. Otherwise, patch will examine either the
> ``old'' and ``new'' file names or, for a non-context diff, the
> ``index'' file name, and choose the file name with the fewest path
> components, the shortest basename, and the shortest total file name
> length (in that order).

(OT: using 'old' first means it'll use "foo.orig" if that's the old path
and my editor uses .orig extension for backup files)

>
> 2. If no file exists, patch checks for the existence of the files in an
> SCCS or RCS directory (using the appropriate prefix or suffix) using
> the criteria specified above. If found, patch will attempt to get
> or check out the file.
>
> 3. If no suitable file was found to patch, the patch file is a context
> or unified diff, and the old file was zero length, the new file name
> is created and used.
>
> 4. If the file name still cannot be determined, patch will prompt the
> user for the file name to use.
>
> I suppose we could implement the method described in step 1.

Which of the two methods described in step 1 do you have in mind?

Whatever we do, the algorithm should be predictable, i.e., a user should
be able to know (from reading a patch) what path it would be applied to.

> That would make us compatible to UNIX patch, and should resolve the two
> use cases I have in mind.
>
> Step 2 doesn't apply to us. Step 3 is used already. Step 4 could be
> implemented as well (but I'd prefer to do that post-1.7).
>
> Thoughts?
>
Received on 2010-09-17 00:43:33 CEST

This is an archived mail posted to the Subversion Dev mailing list.