threads / discuss / 15955

git-svn url-encodes ~ when it should not

Subject: git-svn url-encodes ~ when it should not

## tl;dr

9 messages between Oct 18, 2008 and Oct 24, 2008.

replies: 8people: 4as markdown or json

Björn Steinbrink· Oct 18, 2008, 21:39 UTC · lore
Hi,

Jose Carlos Garcia Sogo reported on #git that a git-svn clone of this svn repo fails for him: https://sucs.org/~welshbyte/svn/backuptool/trunk

I can reproduce that here with: git-svn version 1.6.0.2.541.g46dc1.dirty (svn 1.5.1)

The error message I get is: Apache got a malformed URI: Unusable URI: it does not refer to this repository at /usr/local/libexec/git-core/git-svn line 4057

strace revealed that git-svn url-encodes ~ while svn does not do that.

For svn we have: write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\"> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...

While git-svn shows: write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\"> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...

Björn
Björn Steinbrink· Oct 18, 2008, 22:47 UTC · re: Björn Steinbrink · lore

Re: git-svn url-encodes ~ when it should not

[Adding Jose to Cc:, didn't have his address earlier]
On 2008.10.18 23:39:19 +0200, Björn Steinbrink wrote:
Show 24 quoted lines
> Hi,
> 
> Jose Carlos Garcia Sogo reported on #git that a git-svn clone of this
> svn repo fails for him:
> https://sucs.org/~welshbyte/svn/backuptool/trunk
> 
> I can reproduce that here with:
> git-svn version 1.6.0.2.541.g46dc1.dirty (svn 1.5.1)
> 
> The error message I get is:
> Apache got a malformed URI: Unusable URI: it does not refer to this
> repository at /usr/local/libexec/git-core/git-svn line 4057
> 
> strace revealed that git-svn url-encodes ~ while svn does not do that.
> 
> For svn we have:
> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
> 
> While git-svn shows:
> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
> 
> Björn
Eric Wong· Oct 21, 2008, 21:12 UTC · re: Björn Steinbrink · lore

[PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Thanks to Jose Carlos Garcia Sogo and Björn Steinbrink for the bug report.

On 2008.10.18 23:39:19 +0200, Björn Steinbrink wrote:
Show 22 quoted lines
> Hi,
>
> Jose Carlos Garcia Sogo reported on #git that a git-svn clone of this
> svn repo fails for him:
> https://sucs.org/~welshbyte/svn/backuptool/trunk
>
> I can reproduce that here with:
> git-svn version 1.6.0.2.541.g46dc1.dirty (svn 1.5.1)
>
> The error message I get is:
> Apache got a malformed URI: Unusable URI: it does not refer to this
> repository at /usr/local/libexec/git-core/git-svn line 4057
>
> strace revealed that git-svn url-encodes ~ while svn does not do that.
>
> For svn we have:
> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
>
> While git-svn shows:
> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
Signed-off-by: Eric Wong <normalperson@yhbt.net>
---
 git-svn.perl |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/git-svn.perl b/git-svn.perl
index ef6d773..a97049a 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -852,7 +852,7 @@ sub escape_uri_only {
 	my ($uri) = @_;
 	my @tmp;
 	foreach (split m{/}, $uri) {
-		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
+		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
 		push @tmp, $_;
 	}
 	join('/', @tmp);
@@ -3537,7 +3537,7 @@ sub repo_path {
 sub url_path {
 	my ($self, $path) = @_;
 	if ($self->{url} =~ m#^https?://#) {
-		$path =~ s/([^a-zA-Z0-9_.-])/uc sprintf("%%%02x",ord($1))/eg;
+		$path =~ s/([^~a-zA-Z0-9_.-])/uc sprintf("%%%02x",ord($1))/eg;
 	}
 	$self->{url} . '/' . $self->repo_path($path);
 }
@@ -3890,7 +3890,7 @@ sub escape_uri_only {
 	my ($uri) = @_;
 	my @tmp;
 	foreach (split m{/}, $uri) {
-		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
+		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
 		push @tmp, $_;
 	}
 	join('/', @tmp);
-- 
Eric Wong
Junio C Hamano· Oct 21, 2008, 21:53 UTC · re: Eric Wong · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Eric Wong <normalperson@yhbt.net> writes:
Show 9 quoted lines
>> strace revealed that git-svn url-encodes ~ while svn does not do that.
>>
>> For svn we have:
>> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
>> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
>>
>> While git-svn shows:
>> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
>> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...

This looks like an XML based request sequence to me (and svn is talking WebDAV here, right?); it makes me wonder what exact quoting rules are used there. I would expect $path in <S:src-path>$path</S:src-path> to quote a letters in it e.g. '<' as "&lt;" --- which is quite different from what the s/// substitutions in the patch seem to be doing.

Show 7 quoted lines
> diff --git a/git-svn.perl b/git-svn.perl
> index ef6d773..a97049a 100755
> --- a/git-svn.perl
> +++ b/git-svn.perl
> @@ -852,7 +852,7 @@ sub escape_uri_only {
> -		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
> +		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;

Admittedly I do not know git-svn (nor Perl svn bindings it uses), and I suspect that some of the XML-level escaping is done in the libsvn side, but it would be nice if somebody can at least verify that the code after the patch works with repositories with funny characters in pathnames (perhaps list all the printables including "<&>?*!@.+-%^"). Even nicer would be a log message that says "the resulting code covers all cases because it follows _that_ spec to escape _all_ problematic letters", pointing at some in svn (or libsvn-perl) resource.

The patch may make a path with '~' work, but it (neither in the patch text nor in the commit log message) does not have much to give readers enough confidence that the code after the patch is the _final_ one, as opposed to being just a band-aid for a single symptom that happened to have been discovered this time.

Mike Hommey· Oct 22, 2008, 06:13 UTC · re: Junio C Hamano · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

On Tue, Oct 21, 2008 at 02:53:28PM -0700, Junio C Hamano wrote:
Show 14 quoted lines
> Eric Wong <normalperson@yhbt.net> writes:
> 
> >> strace revealed that git-svn url-encodes ~ while svn does not do that.
> >>
> >> For svn we have:
> >> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> >> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
> >>
> >> While git-svn shows:
> >> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> >> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
> 
> This looks like an XML based request sequence to me (and svn is talking
> WebDAV here, right?);

XML based would be &126;, not %7E. Anyways, aren't there ready-to-use url quoting functions in perl ?

Mike
Junio C Hamano· Oct 22, 2008, 06:24 UTC · re: Mike Hommey · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Mike Hommey <mh@glandium.org> writes:
Show 14 quoted lines
> On Tue, Oct 21, 2008 at 02:53:28PM -0700, Junio C Hamano wrote:
>
>> >> For svn we have:
>> >> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
>> >> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
>> >>
>> >> While git-svn shows:
>> >> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
>> >> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
>> 
>> This looks like an XML based request sequence to me (and svn is talking
>> WebDAV here, right?);
>
> XML based would be &126;, not %7E.
Read what you quoted again and realize you are agreeing with me ;-).

The former (with "~") is what svn expects, the latter (with %7E) is what git-svn incorrectly threw at the server causing problems. I am wondering the whole %xx escaping thing, which does not seem to match what svn seems to expect.

> Anyways, aren't there ready-to-use url quoting functions in perl ?

My question is not about correct "url quoting", but if using "url quoting" is correct in this context.

Eric Wong· Oct 22, 2008, 08:16 UTC · re: Junio C Hamano · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Junio C Hamano <gitster@pobox.com> wrote:
Show 17 quoted lines
> Eric Wong <normalperson@yhbt.net> writes:
> 
> >> strace revealed that git-svn url-encodes ~ while svn does not do that.
> >>
> >> For svn we have:
> >> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> >> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
> >>
> >> While git-svn shows:
> >> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> >> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
> 
> This looks like an XML based request sequence to me (and svn is talking
> WebDAV here, right?); it makes me wonder what exact quoting rules are used
> there.  I would expect $path in <S:src-path>$path</S:src-path> to quote
> a letters in it e.g. '<' as "&lt;" --- which is quite different from what
> the s/// substitutions in the patch seem to be doing.

I agree. I haven't checked if the SVN libraries do proper XML escaping for us (but the problem hasn't shown up yet :). I was already completely disappointed that git-svn had to do its own escaping when transmitting data using the SVN libraries (and dependent on the protocol being used, too!).

Show 16 quoted lines
> > diff --git a/git-svn.perl b/git-svn.perl
> > index ef6d773..a97049a 100755
> > --- a/git-svn.perl
> > +++ b/git-svn.perl
> > @@ -852,7 +852,7 @@ sub escape_uri_only {
> > -		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
> > +		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
> 
> Admittedly I do not know git-svn (nor Perl svn bindings it uses), and I
> suspect that some of the XML-level escaping is done in the libsvn side,
> but it would be nice if somebody can at least verify that the code after
> the patch works with repositories with funny characters in pathnames
> (perhaps list all the printables including "<&>?*!@.+-%^").  Even nicer
> would be a log message that says "the resulting code covers all cases
> because it follows _that_ spec to escape _all_ problematic letters",
> pointing at some in svn (or libsvn-perl) resource.

Help with looking at what SVN does and writing testcases would definitely be appreciated on this matter. Or perhaps this can be done at GitTogether :)

Show 5 quoted lines
> The patch may make a path with '~' work, but it (neither in the patch text
> nor in the commit log message) does not have much to give readers enough
> confidence that the code after the patch is the _final_ one, as opposed to
> being just a band-aid for a single symptom that happened to have been
> discovered this time.

This is definitely a band-aid fix until I or somebody else takes the time to figure out:

 1. exactly which characters need to be escaped
 2. for which protocols those characters need to be escaped
 3. which part(s) of the URI they need to be escaped for
    (repository root vs SVN path)
 4. which versions of SVN needs more (or less) escaping rules
(I vote for somebody else, especially for #4 :)
-- 
Eric Wong
Junio C Hamano· Oct 22, 2008, 18:53 UTC · re: Eric Wong · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Eric Wong <normalperson@yhbt.net> writes:
Show 5 quoted lines
> Junio C Hamano <gitster@pobox.com> wrote:
>
> Help with looking at what SVN does and writing testcases would
> definitely be appreciated on this matter.  Or perhaps this can be done
> at GitTogether :)

I'm not sure it would be a good use of time at GitTogether to do something whose spec is pretty much self-evident (essentially for this one it boils down to "define what are the 'funny' bytes, and list the protocols supported by svn, and come up with paths with funny bytes in it and see what libsvn-perl gives to the underlying svn library, and what the svn library does over the wire"). Ongoiong "fix start-up sequence around worktree area" might be a better fit; I dunno.

Show 16 quoted lines
>> The patch may make a path with '~' work, but it (neither in the patch text
>> nor in the commit log message) does not have much to give readers enough
>> confidence that the code after the patch is the _final_ one, as opposed to
>> being just a band-aid for a single symptom that happened to have been
>> discovered this time.
>
> This is definitely a band-aid fix until I or somebody else takes the
> time to figure out:
>
>  1. exactly which characters need to be escaped
>  2. for which protocols those characters need to be escaped
>  3. which part(s) of the URI they need to be escaped for
>     (repository root vs SVN path)
>  4. which versions of SVN needs more (or less) escaping rules
>
> (I vote for somebody else, especially for #4 :)
Item 3. above disturbs me.  Do you mean that in:
    https://sucs.org/~welshbyte/svn/backuptool/trunk/foo~bar.txt
the two tildes might have to be sent to libsvn-perl differently?

Even if that is the case, I am inclined suggest taking the patch in the meantime as an interim workaround, with the understanding that we know the patch improves the situation for the tilde before welshbyte and even though we do not know if the patch regresses for the latter one between foo and bar, it would be much rarer to have tilde in such places.

Care to come up with an updated log message?
Eric Wong· Oct 24, 2008, 09:13 UTC · re: Junio C Hamano · lore

Re: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs

Junio C Hamano <gitster@pobox.com> wrote:
Show 24 quoted lines
> Eric Wong <normalperson@yhbt.net> writes:
> > Junio C Hamano <gitster@pobox.com> wrote:
> >> The patch may make a path with '~' work, but it (neither in the patch text
> >> nor in the commit log message) does not have much to give readers enough
> >> confidence that the code after the patch is the _final_ one, as opposed to
> >> being just a band-aid for a single symptom that happened to have been
> >> discovered this time.
> >
> > This is definitely a band-aid fix until I or somebody else takes the
> > time to figure out:
> >
> >  1. exactly which characters need to be escaped
> >  2. for which protocols those characters need to be escaped
> >  3. which part(s) of the URI they need to be escaped for
> >     (repository root vs SVN path)
> >  4. which versions of SVN needs more (or less) escaping rules
> >
> > (I vote for somebody else, especially for #4 :)
> 
> Item 3. above disturbs me.  Do you mean that in:
> 
>     https://sucs.org/~welshbyte/svn/backuptool/trunk/foo~bar.txt
> 
> the two tildes might have to be sent to libsvn-perl differently?

Yes, something like this is unfortunately a possibility (as is having to worry about this at all in git-svn).

Show 7 quoted lines
> Even if that is the case, I am inclined suggest taking the patch in the
> meantime as an interim workaround, with the understanding that we know the
> patch improves the situation for the tilde before welshbyte and even
> though we do not know if the patch regresses for the latter one between
> foo and bar, it would be much rarer to have tilde in such places.
> 
> Care to come up with an updated log message?
From aa4f2cdcf64934e13886fabb3b5e986a5cda79f6 Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Tue, 21 Oct 2008 14:12:15 -0700
Subject: [PATCH] git-svn: don't escape tilde ('~') for http(s) URLs
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

This change only fixes the tilde case in the repository URL. A more comprehensive set of escaping rules and tests will be needed in the future for complete compatibility when using uncommon characters.

Thanks to Jose Carlos Garcia Sogo and Björn Steinbrink for the bug report.

On 2008.10.18 23:39:19 +0200, Björn Steinbrink wrote:
Show 22 quoted lines
> Hi,
>
> Jose Carlos Garcia Sogo reported on #git that a git-svn clone of this
> svn repo fails for him:
> https://sucs.org/~welshbyte/svn/backuptool/trunk
>
> I can reproduce that here with:
> git-svn version 1.6.0.2.541.g46dc1.dirty (svn 1.5.1)
>
> The error message I get is:
> Apache got a malformed URI: Unusable URI: it does not refer to this
> repository at /usr/local/libexec/git-core/git-svn line 4057
>
> strace revealed that git-svn url-encodes ~ while svn does not do that.
>
> For svn we have:
> write(5, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/~welshbyte/svn/backuptool/trunk</S:src-path>...
>
> While git-svn shows:
> write(7, "<S:update-report send-all=\"true\" xmlns:S=\"svn:\">
> <S:src-path>https://sucs.org/%7Ewelshbyte/svn/backuptool/trunk</S:src-path>...
Signed-off-by: Eric Wong <normalperson@yhbt.net>
---
 git-svn.perl |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/git-svn.perl b/git-svn.perl
index ef6d773..a97049a 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -852,7 +852,7 @@ sub escape_uri_only {
 	my ($uri) = @_;
 	my @tmp;
 	foreach (split m{/}, $uri) {
-		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
+		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
 		push @tmp, $_;
 	}
 	join('/', @tmp);
@@ -3537,7 +3537,7 @@ sub repo_path {
 sub url_path {
 	my ($self, $path) = @_;
 	if ($self->{url} =~ m#^https?://#) {
-		$path =~ s/([^a-zA-Z0-9_.-])/uc sprintf("%%%02x",ord($1))/eg;
+		$path =~ s/([^~a-zA-Z0-9_.-])/uc sprintf("%%%02x",ord($1))/eg;
 	}
 	$self->{url} . '/' . $self->repo_path($path);
 }
@@ -3890,7 +3890,7 @@ sub escape_uri_only {
 	my ($uri) = @_;
 	my @tmp;
 	foreach (split m{/}, $uri) {
-		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
+		s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
 		push @tmp, $_;
 	}
 	join('/', @tmp);
-- 
Eric Wong

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