git-svn: prevent dcommitting if the index is dirty.

dcommit uses rebase to sync the history with what has just been pushed to
SVN.  Trying to dcommit with a dirty index is troublesome for rebase, so now
the user will get an error message if he attempts to dcommit with a dirty
index.
Signed-off-by: NBenoit Sigoure <tsuna@lrde.epita.fr>
Acked-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-svn.perl

@@ -374,6 +374,9 @@ sub cmd_set_tree {
 
 sub cmd_dcommit {
 	my $head = shift;
+	git_cmd_try { command_oneline(qw/diff-index --quiet HEAD/) }
+		'Cannot dcommit with a dirty index.  Commit your changes first'
+		. "or stash them with `git stash'.\n";
 	$head ||= 'HEAD';
 	my @refs;
 	my ($url, $rev, $uuid, $gs) = working_head_info($head, \@refs);

t/t9106-git-svn-dcommit-clobber-series.sh

@@ -53,4 +53,10 @@ test_expect_success 'change file but in unrelated area' "
 		test x\"\`sed -n -e 61p < file\`\" = x6611
 	"
 
+test_expect_failure 'attempt to dcommit with a dirty index' '
+	echo foo >>file &&
+	git add file &&
+	git svn dcommit
+'
+
 test_done