________________________________
From: David Weintraub [mailto:qazw...@gmail.com]
Sent: Wednesday, January 05, 2011 6:04 PM
To: Berg, Eric: IT (NYK)
Cc: users@subversion.apache.org
Subject: Re: Hooks That Use Perl Test::Builder Having Problems with STDERR
On Wed, Jan 5, 2011 at 5:03 PM, 
<eric.b...@barclayscapital.com<mailto:eric.b...@barclayscapital.com>> wrote:
Dave, if you look into how the hooks work, basically, they are passed a repo 
path and a transaction id that, using svnlook, gives you access to copies of 
the working files, so it doesn't matter where the hooks run, nor is there any 
requirement for server/client communication.

I've written quite a few hooks. I have a hook script that implements watches.  
8<8<

However, I take it that in order to run the tests, you need these files written 
to a directory, and you may need dependent files there too. That starts getting 
a bit more complex than what "svnlook" was built for. In theory, you could 
checkout a working directory on a hook script, then use "svnlook cat" to update 
the files that are being committed, and run your tests. It's complex, and can 
take a long time.

Nonissue.  We've been doing this with CVS hooks for almost 10 years.  It's 
"just a port" ;(....  and I'm not even going to bring up the issues that I will 
undoubtedly run into when I get to work on the DEPLOYMENT piece.

Even after all of that, Subversion captures STDOUT and STDERR and they don't 
get printed out to a console. If you want to see them, you'll have to capture 
them and then either write them to a logfile, or email them.

This is a larger issue for us, specifically WRT the Test::Builder tests that 
we've implemented.  The way this was done was to make any Perl class which 
required tests to be a subclass of our UnitTest class, which runs any 
subroutines with names that begin with "test_".  Each of these has some number 
of Test::* tests.  With CVS, we see the progress of the tests as they complete 
-- whether they succeed or fail.  With SVN, we'd only see failures.

This is where I'm having some issues with the STDERR output.  I haven't dug 
down deeply enough understand the impace of the "stacked redirection" of SVN's 
doing a STDERR/OUT capture, then the Test::* mods doing their own redirect.  
What i have seen is that the only place that the stderr appears once these 
tests are run is the web server logs.  A simple test which simply dies in my 
precommit hook shows up fine to the client's stderr.

Though I do love immediate checkins, I'm not sure where you're going when you 
suggest that our validations might be better handled some way other than by 
hooks.  That appears to be the whole reason to have such hooks:  to validate 
files before allowing a checkin.

How long does it take your pre-commit hook to run? Even a few seconds can seem 
like an eternity to a developer who is making a few minor changes. If every 
time a developer does a commit, they have to wait, they simply will stop making 
commits when they should. And, they'll learn to hate Subversion because it is 
slow and buggy.

Don't forget that this has been the standard for our checkins here since time 
immemorial.   Developers are pretty much used to it, if not simply resigned.  I 
appreciate the stringent code validation regime that enforces a number of 
checks in addition to the unit tests.

It can take from 30 seconds up to several minutes.  For database code, often, 
actual temporary deploys are followed by tests to validate what's been deployed 
are  valid before allowing the checkins to continue.  Again, this seems like a 
good place NOT to mention our CVS tag-based deploys, which can take a VERY long 
time to deploy to our ~40 db's, etc.
Remember that Subversion is a version control system which means you can undo 
stuff that should never have been committed in the first place. Doing tests 
during the build cycle has lots of advantages:

I'm in the middle here, being the developer responsible for this porting 
project.  I mentioned the deployment stuff too, which I fear, and which I fear 
is far less appropriate to be implemented via SVN hooks.  Your input is 
appreciated.  We could go back-and-forth endlessly, but ultimately, it's not my 
decision.  There's a lot of inertia influencing this as well, not to mention 
that this is just one of my projects, and that our organization has 
discontinued support for CVS, so we're kind of working without a net at the 
moment.

Not sure how this is going to go, but the input is, again, appreciated.

* You have room to checkout your entire project and have access to all the 
files. That can make running your tests much simpler to do.
* You can use Hudson as your framework (or another build server). That means 
the reporting, running, and checking the results are all done for you. There's 
no reinventing the wheel.
 * Your commits are now much faster.
* Your tests have their own environment and won't interfere with Subversion
* You have a complete log of your tests, and you can review it and see if 
things are improving.
* You have time and resources for more thorough testing
* You can notify the entire team when there's an issue. There's always a good 
chance that the problem isn't in the file being committed, but is located 
elsewhere.
* Most importantly, you'll make your life a lot easier. All you have to do is 
write the tests and not worry about how you'll run the tests, or how you'll get 
the output from the tests.

It is definitely possible to do what you want, but it will take a lot of work 
and will probably cause more problems than it is worth..

--
David Weintraub
qazw...@gmail.com<mailto:qazw...@gmail.com>

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