git tool to keep a subversion mirror

git tool to keep a subversion mirror

[Sergey Yanovich]

I am actively using git for my project. Thanks everyone envolved.

However, I got tired of administering own web server and registered my
project at sourceforge. Unlike repo.or.cz (thanks again for everyone
envolved), they do not provide git hosting. But a project without a
source repository is non-sence.

I am not in any way going to use Subversion after I tried git, but I
need to be able to export to a Subversion repository. I found an
excellent tool called 'git-svn'. However, the flawed nature of
Subversion put shackles on normal git usage after you do 'git-svn init'.

Since git is the best scm system, my situation is probably quite common.
So I am filing these patches.

There is a 'git-svn' command which does want I need, so I created a
simple wrapper around it. I also found that 'git-svn commit-diff' is
having a small trouble dealing with root <tree-ish>, which is corrected
by an attached patch.

git tool to keep a subversion mirror

[Sergey Yanovich]

Oops, failed to attach patches last time

[PATCH 1/2] Accept root <tree-ish> in 'git-svn commit-diff'

[Sergey Yanovich]

Signed-off-by: Sergey Yanovich <ynvich@gmail.com>
---
 git-svn.perl |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/git-svn.perl b/git-svn.perl
index 50128d7..8ad291b 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -2572,7 +2572,12 @@ sub generate_diff {
 	}
 	push @diff_tree, '--find-copies-harder' if $_find_copies_harder;
 	push @diff_tree, "-l$_rename_limit" if defined $_rename_limit;
-	push @diff_tree, $tree_a, $tree_b;
+	if ($tree_a eq '0000000000000000000000000000000000000000') {
+		push @diff_tree, '--root';
+	} else {
+		push @diff_tree, $tree_a;
+	}
+	push @diff_tree, $tree_b;
 	my ($diff_fh, $ctx) = command_output_pipe(@diff_tree);
 	local $/ = "\0";
 	my $state = 'meta';
@@ -2606,6 +2611,8 @@ sub generate_diff {
 			}
 			$x->{file_b} = $_;
 			$state = 'meta';
+		} elsif ($state eq 'meta' && $_ eq $tree_b &&
+			$tree_a eq '0000000000000000000000000000000000000000') {
 		} else {
 			croak "Error parsing $_\n";
 		}
-- 
1.5.2.1

[PATCH 2/2] 'git-svndump'

[Sergey Yanovich]

Signed-off-by: Sergey Yanovich <ynvich@gmail.com>
---
 Documentation/git-svndump.txt |  106 +++++++++++++++++++++++++++++++++++++++++
 git-svndump-init.sh           |   85 +++++++++++++++++++++++++++++++++
 git-svndump-sync.sh           |   85 +++++++++++++++++++++++++++++++++
 3 files changed, 276 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/git-svndump.txt
 create mode 100755 git-svndump-init.sh
 create mode 100755 git-svndump-sync.sh

diff --git a/Documentation/git-svndump.txt b/Documentation/git-svndump.txt
new file mode 100644
index 0000000..9caf02b
--- /dev/null
+++ b/Documentation/git-svndump.txt
@@ -0,0 +1,106 @@
+git-svndump(1)
+==========
+
+NAME
+----
+git-svndump - Exporting from git to a single Subversion branch
+
+SYNOPSIS
+--------
+'git-svndump' <command> [options] [arguments]
+
+DESCRIPTION
+-----------
+git-svndump is essentially a wrapper around 'git-svn commit-diff'. It
+will work only when it is the sole method of committing to the
+Subversion repository.
+
+It is designed to export a linear git branch. However, thanks to the way
+'git' handles source code, 'git-svndump' seems to work in other
+conditions. For example, when branches are switched or merged.
+
+git-svndump provides a solution when you need to export you source code
+in Subversion format (who would need this with git :), but do not want
+to have all the shackles that 'git-svn init' puts on your repository.
+
+COMMANDS
+--------
+--
+
+'init'::
+	Initialize an existing git repository with additional
+	metadata directories for git-svndump.  The Subversion URL
+	must be specified as the first non-optional command-line
+	argument. 'git' tree-ish that correspond to the HEAD of
+	that Subversion URL may be specified as the second optional
+	command-line argument.
+
+-f;;
+	git-svndump normally declines to reinitialize the same git
+	repository. With the '-f' option that behavior is overridden.
+
+-A<filename>;;
+--authors-file=<filename>;;
+	The filename is stored, and provided as an argument to 'git-svn'
+	on calls of 'git-svndump sync'.
+
+'sync'::
+	Commit git revisions to the Subversion repository. If a git
+	<tree-ish> is specified as an optional command-line argument,
+	than all commits between the last 'sync' and that <tree-ish> are
+	send. If the argument is omitted, the HEAD of the active branch
+	is used.
+
+-A<filename>;;
+--authors-file=<filename>;;
+	The filename is provided as an argument to 'git-svn'.
+
+--
+
+BASIC EXAMPLE
+--------------
+
+Contributing to a Subversion repository:
+
+------------------------------------------------------------------------
+# Create your git repository, do some work and commit your  changes
+# You are working on a computer A (git.foo.org)
+# Prepare your git repository for export (you are in the top dir)
+	git-svndump-init -A .auth http://svn.foo.org/project
+# Commit the whole branch:
+	git-svndump-sync
+# Now you go a different computer B
+# Clone a git repo:
+	git clone git.foo.org:/path/to/project.git
+# Enter the newly cloned directory:
+	cd project
+# Immediately prepare the new repository for export
+	git-svndump-init -A .auth http://svn.foo.org/project HEAD
+# Do some work and commit both locally and to A:
+	git commit ...
+	git push
+# Commit the new work:
+	git-svndump-sync
+# Now you return to the computer A
+# Reinit your repository for export!
+	git-svndump-init -f -A .auth http://svn.foo.org/project HEAD
+------------------------------------------------------------------------
+
+BUGS
+----
+
+The HEAD of the Subversion repository is not tracked. If your
+git-svndump repository goes out-of-sync with the Subversion mirror,
+the latter will most probably be corrupted.
+
+SEE ALSO
+--------
+gitlink:git-svn[1]
+
+Author
+------
+Written by Sergey Yanovich <ynvich@gmail.com>.
+
+Documentation
+-------------
+Written by Sergey Yanovich <ynvich@gmail.com>.
diff --git a/git-svndump-init.sh b/git-svndump-init.sh
new file mode 100755
index 0000000..4cf61b8
--- /dev/null
+++ b/git-svndump-init.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+
+usage()
+{
+	cat << EOF
+Usage: git-svndump-init [-f] subversion-url [<commit>]
+  subversion-url -- URL of the subversion repository to which you want
+                    to dump the current git repository
+  <commit>       -- git <commit> that correspond to the latest revision
+                    in the subversion repository
+OPTIONS
+  -f
+  		 do not stop, if the git repository is already initialized.
+EOF
+	exit 1
+}
+
+if test x$GIT_DIR = x ; then
+	if test -d ./.git ; then
+		GIT_DIR=`pwd`/.git
+	fi
+fi
+
+if test ! -d $GIT_DIR ; then
+	usage
+fi
+
+if test x$1 = x ; then
+	usage 
+fi
+
+if test x$1 = x-f; then
+	shift
+	rm -rf $GIT_DIR/svndump
+fi
+
+if test -d $GIT_DIR/svndump ; then
+	echo git-svndump-init: error: This git repository is already initialized
+	exit 1
+fi
+
+mkdir $GIT_DIR/svndump
+if test ! -d $GIT_DIR/svndump ; then
+	echo git-svndump-init: error: Failed to create $GIT_DIR/svndump
+	exit 1
+fi
+
+rev=`svn info $1 >$GIT_DIR/svndump/error.log`
+if test $? -ne 0 ; then
+	echo git-svndump-init: error: While quering $1
+	rm -rf $GIT_DIR/svndump
+	exit 1
+fi
+
+rev=`cat $GIT_DIR/svndump/error.log | sed -ne "/Revision/s/.* //p"`
+rm $GIT_DIR/svndump/error.log
+
+if test x$rev = x ; then
+	echo "git-svndump-init: error: Cannot determine the latest revision"
+	echo "                         at $1"
+	rm -rf $GIT_DIR/svndump
+	exit 1
+fi
+
+if test $rev -eq 0 ; then
+	mkdir -p $GIT_DIR/svndump/import && cd $GIT_DIR/svndump/import &&
+	svn import . $1 -m "Initial import by git-svndump"
+	if test $? -ne 0 ; then
+		echo "git-svndump-init: error: Failed to init $1"
+		rm -rf $GIT_DIR/svndump
+		exit 1
+	fi
+	rmdir $GIT_DIR/svndump/import
+fi
+
+echo "$1" > $GIT_DIR/svndump/url
+
+if test x$2 != x ; then
+	commit=`GIT_DIR=$GIT_DIR git-rev-list --max-count=1 $2`
+	if test $? -ne 0 ; then
+		echo "git-svndump-init: warning: Bad commit $2 ignored"
+	else
+		echo $commit >> $GIT_DIR/svndump/last
+	fi
+fi
diff --git a/git-svndump-sync.sh b/git-svndump-sync.sh
new file mode 100755
index 0000000..e1c04e1
--- /dev/null
+++ b/git-svndump-sync.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+
+usage()
+{
+	cat << EOF
+Usage: git-svndump-sync [<commit>]
+  <commit>       -- git <commit> that correspond to the latest revision
+                    to be dumped to the subversion repository
+EOF
+	exit 1
+}
+
+if test x$GIT_DIR = x ; then
+	if test -d ./.git ; then
+		GIT_DIR=`pwd`/.git
+	fi
+fi
+
+if test ! -d $GIT_DIR ; then
+	usage
+fi
+
+if test ! -d $GIT_DIR/svndump ; then
+	echo "git-svndump-sync: error: This git repository is not initialized"
+	echo "                         Run git-svndump-init first"
+	exit 1
+fi
+
+if test ! -f $GIT_DIR/svndump/url ; then
+	echo "git-svndump-sync: error: Cannot read url"
+	exit 1
+fi
+
+url=`cat $GIT_DIR/svndump/url`
+rev=`svn info $url >$GIT_DIR/svndump/error.log`
+if test $? -ne 0 ; then
+	echo git-svndump-sync: error: While quering $url
+	rm -rf $GIT_DIR/svndump/error.log
+	exit 1
+fi
+
+rev=`cat $GIT_DIR/svndump/error.log | sed -ne "/Revision/s/.* //p"`
+rm $GIT_DIR/svndump/error.log
+
+if test x$rev = x ; then
+	echo "git-svndump-init: error: Cannot determine the latest revision"
+	echo "                         at $url"
+	exit 1
+fi
+
+if test x$1 = x ; then
+	commit=HEAD
+else
+	commit=`GIT_DIR=$GIT_DIR git-rev-list --max-count=1 $1`
+	if test $? -ne 0 ; then
+		echo "git-svndump-sync: error: Bad commit '$1'"
+		exit 1
+	fi
+fi
+
+start=""
+last=0000000000000000000000000000000000000000
+if test -f $GIT_DIR/svndump/last ; then
+	last=`cat $GIT_DIR/svndump/last`
+	start=^`GIT_DIR=$GIT_DIR git-rev-list --max-count=1 $last`
+	if test $? -ne 0 ; then
+		echo "git-svndump-sync: warning: Ignoring bad commit '$last'"
+		start=""
+		last=0000000000000000000000000000000000000000
+	fi
+fi
+
+list=`GIT_DIR=$GIT_DIR git-rev-list $commit $start`
+
+diffs=""
+for c in $list ; do
+	diffs="$c $diffs"
+done
+
+for c in $diffs ; do
+	GIT_DIR=$GIT_DIR git-svn commit-diff -r$rev $last $c $url
+	echo "$c" > $GIT_DIR/svndump/last
+	last=$c
+	let rev++
+done
-- 
1.5.2.1

Re: git tool to keep a subversion mirror

[Matthieu Moy]

Sergey Yanovich <ynvich@gmail.com> writes:

> which is corrected by an attached patch.

I believe you forgot it then ... ;-)

-- 
Matthieu

Re: git tool to keep a subversion mirror

[Sergey Yanovich]

Matthieu Moy wrote:
>> which is corrected by an attached patch.
> 
> I believe you forgot it then ... ;-)
> 
Absolutely right. Forgot to add a dir in the end. But I noticed that, 
and send a catch-up:

git-send-email --to git () vger . kernel.org --to normalperson () 
yhbt.net --chain-reply-to --subject "git tool to keep a subversion 
mirror" --compose --in-reply-to 11821061823423-git-send-email-ynvich () 
gmail.com /tmp/out/

Here, I replace @ with ' () ' in the above for some anti-bot protection.

However, '--chain-reply-to' seems to have failed. The patches (2 of 
them) came as top-level posts. Or I may be doing something wrong.

--
  Sergey Yanovich

git tool to keep a subversion mirror

[Sergey Yanovich]

On 6/18/07, Sergey Yanovich <ynvich@gmail.com> wrote:
> However, '--chain-reply-to' seems to have failed. The patches (2 of
> them) came as top-level posts. Or I may be doing something wrong.

I should have used '--thread' and '--in-reply-to=' when I was formating
the patches. It should be correctied this time.

Sorry for being akward :)

--
 Sergey Yanovich

git tool to keep a subversion mirror

[Sergey Yanovich]

Johannes Sixt wrote:
> It is extremely difficult to tell whether the patch makes sense or is
> correct, if there is _no_ explanation what it is good for.

I agree 100%. I sent a fore-letter using git-send-email, but all parts got split. 

Pasting it manually:

> I am actively using git for my project. Thanks everyone envolved.
> 
> However, I got tired of administering own web server and registered my
> project at sourceforge. Unlike repo.or.cz (thanks again for everyone
> envolved), they do not provide git hosting. But a project without a
> source repository is non-sence.
> 
> I am not in any way going to use Subversion after I tried git, but I
> need to be able to export to a Subversion repository. I found an
> excellent tool called 'git-svn'. However, the flawed nature of
> Subversion put shackles on normal git usage after you do 'git-svn init'.
> 
> Since git is the best scm system, my situation is probably quite common.
> So I am filing these patches.
> 
> There is a 'git-svn' command which does want I need, so I created a
> simple wrapper around it. I also found that 'git-svn commit-diff' is
> having a small trouble dealing with root <tree-ish>, which is corrected
> by an attached patch.

git tool to keep a subversion mirror

[Sergey Yanovich]

A set of patches updated with comments from this list follows.

Thanks for your time.

Re: git tool to keep a subversion mirror

[Jan Hudec]

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On Sun, Jun 17, 2007 at 21:49:42 +0300, Sergey Yanovich wrote:
> I am actively using git for my project. Thanks everyone envolved.
> 
> However, I got tired of administering own web server and registered my
> project at sourceforge. Unlike repo.or.cz (thanks again for everyone
> envolved), they do not provide git hosting. But a project without a
> source repository is non-sence.

It is. But project on sourceforge with source repository on repo.or.cz is
perfectly ok.

Providing subversion interface to your project might make sense, but on the
other hand you probably want your potential contributors make contributions
with git and not with subversion.

As yet another alternative you might want to go to some other hosting. Maybe
http://en.wikipedia.org/wiki/Comparison_of_free_software_hosting_facilities
could be good starting point for looking for some.

-- 
						 Jan 'Bulb' Hudec <bulb@ucw.cz>

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