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From: Jonathan Nieder <jrnieder@gmail.com>
To: normalperson@yhbt.net
Cc: "Michael G. Schwern" <schwern@pobox.com>,
	git@vger.kernel.org, gitster@pobox.com, robbat2@gentoo.org,
	bwalton@artsci.utoronto.ca
Subject: Re: [PATCH 4/7] Add join_paths() to safely concatenate paths.
Date: Wed, 26 Sep 2012 13:51:22 -0700	[thread overview]
Message-ID: <20120926205122.GA29906@elie.Belkin> (raw)
In-Reply-To: <1343468312-72024-5-git-send-email-schwern@pobox.com>

Hi,

Michael G. Schwern wrote:

> Otherwise you might wind up with things like...
>
>     my $path1 = undef;
>     my $path2 = 'foo';
>     my $path = $path1 . '/' . $path2;
>
> creating '/foo'.  Or this...
>
>     my $path1 = 'foo/';
>     my $path2 = 'bar';
>     my $path = $path1 . '/' . $path2;
>
> creating 'foo//bar'.

I'm still puzzled by this one, too.  I don't understand the
motivation.  Is this to make joining paths less fragile, by preserving
the property that join_paths($a, $b) names the directory you would get
to by first chdir-ing into $a and then into $b?

It would be easier to understand as two patches: first, one that
extracts join_paths without any functional change, and then one that
changes its implementation with an explanation for what positive
functional effect that would have.

> --- a/git-svn.perl
> +++ b/git-svn.perl
[...]
> @@ -1275,7 +1276,7 @@ sub get_svnprops {
>  	$path = $cmd_dir_prefix . $path;
>  	fatal("No such file or directory: $path") unless -e $path;
>  	my $is_dir = -d $path ? 1 : 0;
> -	$path = $gs->{path} . '/' . $path;
> +	$path = join_paths($gs->{path}, $path);
>  
>  	# canonicalize the path (otherwise libsvn will abort or fail to
>  	# find the file)

This can't be for the //-collapsing effect since the path is about
to be canonicalized.  It can't be for the initial-/ effect since
that is stripped away by canonicalization, too.

So no functional effect here, good or bad.

[...]
> --- a/perl/Git/SVN.pm
> +++ b/perl/Git/SVN.pm
[...]
> @@ -316,9 +320,7 @@ sub init_remote_config {
>  			}
>  			my $old_path = $self->path;
>  			$url =~ s!^\Q$min_url\E(/|$)!!;
> -			if (length $old_path) {
> -				$url .= "/$old_path";
> -			}
> +			$url = join_paths($url, $old_path);
>  			$self->path($url);

This is probably not for the normal //-collapsing effect because
$url already has its trailing / stripped off.  Maybe it is for
cases where $old_path has leading slashes or $min_url has multiple
trailing ones?

In the end it shouldn't make a difference, once a later patch teaches
Git::SVN->path to canonicalize.

Is the functional change in this patch for aesthetic reasons, or is
there some other component (perhaps in a later patch) that relies on
it?

Thanks again for your help,
Jonathan

  reply	other threads:[~2012-09-26 20:51 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-28  9:38 Canonicalize the git-svn path & url accessors Michael G. Schwern
2012-07-28  9:38 ` [PATCH 1/7] Move the canonicalization functions to Git::SVN::Utils Michael G. Schwern
2012-07-28  9:38 ` [PATCH 2/7] Change canonicalize_url() to use the SVN 1.7 API when available Michael G. Schwern
2012-07-28 13:50   ` Jonathan Nieder
2012-07-28 19:01     ` Michael G Schwern
2012-07-28 19:30       ` Jonathan Nieder
2012-07-28 19:51         ` Michael G Schwern
2012-07-28 19:57           ` Jonathan Nieder
2012-07-28 20:02             ` Jonathan Nieder
2012-07-28 20:24               ` Michael G Schwern
2012-10-14 11:42       ` [PATCH/RFC 0/2] " Jonathan Nieder
2012-10-14 11:45         ` [PATCH 1/2] git svn: do not overescape URLs (fallback case) Jonathan Nieder
2012-10-14 11:48         ` [PATCH 2/2] git svn: canonicalize_url(): use svn_path_canonicalize when available Jonathan Nieder
2012-10-23 22:58           ` Eric Wong
2012-07-28  9:38 ` [PATCH 3/7] Extract, test and enhance the logic to collapse ../foo paths Michael G. Schwern
2012-07-30 19:51   ` Eric Wong
2012-07-30 20:46     ` Michael G Schwern
2012-09-26 19:45       ` Jonathan Nieder
2012-09-26 20:58         ` Eric Wong
2012-09-26 21:38           ` Jonathan Nieder
2012-09-26 21:54             ` Eric Wong
2012-09-26 22:43               ` Jonathan Nieder
2012-09-27  0:15                 ` Eric Wong
2012-09-27  2:11                   ` Jonathan Nieder
2012-07-28  9:38 ` [PATCH 4/7] Add join_paths() to safely concatenate paths Michael G. Schwern
2012-09-26 20:51   ` Jonathan Nieder [this message]
2012-07-28  9:38 ` [PATCH 5/7] Remove irrelevant comment Michael G. Schwern
2012-07-28  9:38 ` [PATCH 6/7] Switch path canonicalization to use the SVN API Michael G. Schwern
2012-07-28 13:55   ` Jonathan Nieder
2012-07-28 19:07     ` Michael G Schwern
2012-07-30 20:04       ` Eric Wong
2012-08-02 21:51         ` Eric Wong
2012-08-02 23:18           ` Michael G Schwern
2012-10-05  7:04       ` [PATCH] git-svn: keep leading slash when canonicalizing paths (fallback case) Jonathan Nieder
2012-10-05 23:12         ` Eric Wong
2012-10-06  5:36           ` Junio C Hamano
2012-07-28  9:38 ` [PATCH 7/7] Make Git::SVN and Git::SVN::Ra canonicalize paths and urls Michael G. Schwern
2012-07-28 14:11   ` Jonathan Nieder
2012-07-28 19:15     ` Michael G Schwern

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