From: Kyle McKay <mackyle@gmail.com>
Date: Sun, 07 Jul 2013 02:13:42 GMT
Subject: Re: [PATCH 2/2] git-svn: allow git-svn fetching to work using serf
Message-ID: <8CACBE8F-8672-43AB-882E-4ADA05B4D822@gmail.com>
In-Reply-To: <20130707002430.GE30132@google.com>

On Jul 6, 2013, at 17:24, Jonathan Nieder wrote:
> (cc-ing Eric Wong, who wrote this code)
> Hi,
>
> Kyle McKay wrote:
>
>> Temp file with moniker 'svn_delta' already in use at Git.pm line 1250
>> Temp file with moniker 'git_blob' already in use at Git.pm line 1250
>>
>> David Rothenberger <daveroth@acm.org> has determined the cause to
>> be that ra_serf does not drive the delta editor in a depth-first
>> manner [...]. Instead, the calls come in this order:
> [...]
>> --- a/perl/Git/SVN/Fetcher.pm
>> +++ b/perl/Git/SVN/Fetcher.pm
>> @@ -315,11 +315,13 @@ sub change_file_prop {
>> sub apply_textdelta {
>> 	my ($self, $fb, $exp) = @_;
>> 	return undef if $self->is_path_ignored($fb->{path});
>> -	my $fh = $::_repository->temp_acquire('svn_delta');
>> +	my $suffix = 0;
>> +	++$suffix while $::_repository->temp_is_locked("svn_delta_${$}_ 
>> $suffix");
>> +	my $fh = $::_repository->temp_acquire("svn_delta_${$}_$suffix");
>> 	# $fh gets auto-closed() by SVN::TxDelta::apply(),
>> 	# (but $base does not,) so dup() it for reading in close_file
>> 	open my $dup, '<&', $fh or croak $!;
>> -	my $base = $::_repository->temp_acquire('git_blob');
>> +	my $base = $::_repository->temp_acquire("git_blob_${$}_$suffix");
>
> Thanks for your work tracking this down.
>
> I'm a bit confused.  Are you saying that apply_textdelta gets called
> multiple times in a row without an intervening close_file?

Unless bulk updates are disabled when using the serf access method  
(the only one available with svn 1.8) for https?: urls,  
apply_textdelta does indeed get called multiple times in a row without  
an intervening temp_release.

Two temp files are created for each apply_textdelta ('svn_delta...'  
and 'git_blob...').  In my tests it seems that most of the time the  
two temp files are enough, but occasionally as many as six will be  
open at the same time.

I suspect this maximum number is related to the maximum number of  
simultaneous connections the serf access method will use which  
defaults to 4.  Therefore I would expect to see as many as 8 temp  
files (4 each for 'svn_delta...' and 'git_blob...'), but I have only  
been able to trigger creation of 6 temp files so far.

Kyle