patch, 3 partsAccept root <tree-ish> in 'git-svn commit-diff'

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";
 		}

Documentation/git-svndump.txt, git-svndump-init.sh, 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

diff --git a/git-svndump-sync.sh b/git-svndump-sync.sh
index e1c04e1..516edaf 100755
--- a/git-svndump-sync.sh
+++ b/git-svndump-sync.sh
@@ -70,7 +70,14 @@ if test -f $GIT_DIR/svndump/last ; then
 	fi
 fi
 
-list=`GIT_DIR=$GIT_DIR git-rev-list $commit $start`
+while true ; do
+
+list=`GIT_DIR=$GIT_DIR git-rev-list --no-merges --topo-order $commit $start |
+tail -n 8`
+
+if test -z "$list" ; then
+	exit 0
+fi
 
 diffs=""
 for c in $list ; do
@@ -79,7 +86,14 @@ done
 
 for c in $diffs ; do
 	GIT_DIR=$GIT_DIR git-svn commit-diff -r$rev $last $c $url
+	if test $? -ne 0 ; then
+		exit $?
+	fi
 	echo "$c" > $GIT_DIR/svndump/last
 	last=$c
 	let rev++
 done
+
+start=^$last
+
+done