[Discuss] Any Subversion geniuses out there?

[matt at mattshields.org (Matt Shields)]

On Fri, Dec 2, 2011 at 8:11 AM, Edward Ned Harvey <blu at nedharvey.com> wrote:

> > From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> > bounces+blu=nedharvey.com at blu.org] On Behalf Of Matt Shields
> >
> >  What I was wondering is it possible in Subversion when a changeset is
> > being committed that a hook could be used to change the mime-type.  So if
> > the file being committed is a *.sql, then it would override whatever
> > mime-type the client is saying and apply text/x-sql.
>
> This question will be best answered by the subversion-users mailing list,
> http://subversion.apache.org/mailing-lists.html
> but let's see what we can say about it here.
>
> The mime type, I believe, is determined by the svn client, and it's
> determined by file contents.  What do you get, if you run linux "file" on
> the file?  What do you see if you try to open the file in vim or emacs?
>
> I'm sure you can change the mime-type as a precommit or postcommit hook
> (probably best precommit) but I'm almost equally sure that it's not what
> you
> want to do.  When they detect the contents and select a mime type, the
> reason they're doing it is because svn internally employs all sorts of diff
> and compression algorithms, to optimize both the network traffic and disk
> storage.  If you go overriding the mime types against its natural wishes,
> you run the risk of ...  Suboptimizing performance.  Is probably the
> diplomatic way of saying effing everything up.
>
> Another option you might consider, I believe, is that they have a mechanism
> of some kind to allow you to inject a custom client-side diff utility for
> certain files or mime types or something like that.  You might configure it
> so that your client doing the diff might run something like the SQL
> equivalent of "dos2unix" to convert a file format and then diff it, or
> something like that.  Of course the odds of success doing this are
> diminished by trac.  You might just have to use something like tortoisesvn
> or whatever to perform these diffs.
>
> In fact, tortoisesvn does some pretty excellent diffing.  What happens if
> you try diffing with tortoise?
>
>
Yes, I'm aware of that, and I can put something in each client's svnconfig
to override this behavior for specific filetypes.  I don't want to have to
do that since everytime we get a new developer it's one more step I have to
remember to do to their dev machine.

The issue is SQL Server Management Studio is encoding it weird and
TortoiseSVN is then taking that as it being a binary and not a text file.
 See the two outputs of file.  The first has been fixed by me forcing it to
be proper encoding and the proper mime-type.  The second was created in
SSMS and committed.

dbo.Proc_xxxx.sql:         Little-endian UTF-16 Unicode c program text,
with CRLF, CR line terminators
dbo.Proc_yyyy.sql:                 ASCII c program text, with CRLF line
terminators

Yes, diff's in TortoiseSVN are great, same with Unix command line.  The
issue is the Dir of Tech prefer's to use Trac to review all changes, and
because it's encoded wrong, that means svn is applying the wrong mime-type
which causes Trac's diff feature not to work.

In this case I don't believe there is any harm forcing svn to use a
specific mime-type since they are both text. I'll check out the
check-mime-type.pl that Greg mentioned.

Matthew Shields
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