git-svn: fix dcommit losing changes when out-of-date from svn

There was a bug in dcommit (and commit-diff) which caused deltas
to be generated against the latest version of the changed file
in a repository, and not the revision we are diffing (the tree)
against locally.

This bug can cause recent changes to the svn repository to be
silently clobbered by git-svn if our repository is out-of-date.

Thanks to Steven Grimm for noticing the bug.

The (few) people using the commit-diff command are now required
to use the -r/--revision argument.  dcommit usage is unchanged.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-svn.txt

@@ -120,6 +120,7 @@ manually joining branches on commit.
 	URL of the target Subversion repository.  The final argument
 	(URL) may be omitted if you are working from a git-svn-aware
 	repository (that has been init-ed with git-svn).
+	The -r<revision> option is required for this.
 
 'graft-branches'::
 	This command attempts to detect merges/branches from already

git-svn.perl

@@ -134,6 +134,7 @@ sub nag_lib {
 	'commit-diff' => [ \&commit_diff, 'Commit a diff between two trees',
 			{ 'message|m=s' => \$_message,
 			  'file|F=s' => \$_file,
+			  'revision|r=s' => \$_revision,
 			%cmt_opts } ],
 	dcommit => [ \&dcommit, 'Commit several diffs to merge with upstream',
 			{ 'merge|m|M' => \$_merge,
@@ -586,11 +587,21 @@ sub commit_lib {
 sub dcommit {
 	my $gs = "refs/remotes/$GIT_SVN";
 	chomp(my @refs = safe_qx(qw/git-rev-list --no-merges/, "$gs..HEAD"));
+	my $last_rev;
 	foreach my $d (reverse @refs) {
+		unless (defined $last_rev) {
+			(undef, $last_rev, undef) = cmt_metadata("$d~1");
+			unless (defined $last_rev) {
+				die "Unable to extract revision information ",
+				    "from commit $d~1\n";
+			}
+		}
 		if ($_dry_run) {
 			print "diff-tree $d~1 $d\n";
 		} else {
-			commit_diff("$d~1", $d);
+			if (my $r = commit_diff("$d~1", $d, undef, $last_rev)) {
+				$last_rev = $r;
+			} # else: no changes, same $last_rev
 		}
 	}
 	return if $_dry_run;
@@ -814,6 +825,8 @@ sub commit_diff {
 		print STDERR "Needed URL or usable git-svn id command-line\n";
 		commit_diff_usage();
 	}
+	my $r = shift || $_revision;
+	die "-r|--revision is a required argument\n" unless (defined $r);
 	if (defined $_message && defined $_file) {
 		print STDERR "Both --message/-m and --file/-F specified ",
 				"for the commit message.\n",
@@ -830,13 +843,22 @@ sub commit_diff {
 	($repo, $SVN_PATH) = repo_path_split($SVN_URL);
 	$SVN_LOG ||= libsvn_connect($repo);
 	$SVN ||= libsvn_connect($repo);
+	if ($r eq 'HEAD') {
+		$r = $SVN->get_latest_revnum;
+	} elsif ($r !~ /^\d+$/) {
+		die "revision argument: $r not understood by git-svn\n";
+	}
 	my @lock = $SVN::Core::VERSION ge '1.2.0' ? (undef, 0) : ();
-	my $ed = SVN::Git::Editor->new({	r => $SVN->get_latest_revnum,
+	my $rev_committed;
+	my $ed = SVN::Git::Editor->new({	r => $r,
 						ra => $SVN_LOG, c => $tb,
 						svn_path => $SVN_PATH
 					},
 				$SVN->get_commit_editor($_message,
-					sub {print "Committed $_[0]\n"},@lock)
+					sub {
+						$rev_committed = $_[0];
+						print "Committed $_[0]\n";
+					}, @lock)
 				);
 	my $mods = libsvn_checkout_tree($ta, $tb, $ed);
 	if (@$mods == 0) {
@@ -846,6 +868,7 @@ sub commit_diff {
 		$ed->close_edit;
 	}
 	$_message = $_file = undef;
+	return $rev_committed;
 }
 
 ########################### utility functions #########################

t/t9105-git-svn-commit-diff.sh

@@ -33,7 +33,7 @@ prev=`git rev-parse --verify HEAD^1`
 
 test_expect_success 'test the commit-diff command' "
 	test -n '$prev' && test -n '$head' &&
-	git-svn commit-diff '$prev' '$head' '$svnrepo' &&
+	git-svn commit-diff -r1 '$prev' '$head' '$svnrepo' &&
 	svn co $svnrepo wc &&
 	cmp readme wc/readme
 	"

t/t9106-git-svn-commit-diff-clobber.sh

@@ -0,0 +1,74 @@
+#!/bin/sh
+#
+# Copyright (c) 2006 Eric Wong
+test_description='git-svn commit-diff clobber'
+. ./lib-git-svn.sh
+
+if test -n "$GIT_SVN_NO_LIB" && test "$GIT_SVN_NO_LIB" -ne 0
+then
+	echo 'Skipping: commit-diff clobber needs SVN libraries'
+	test_done
+	exit 0
+fi
+
+test_expect_success 'initialize repo' "
+	mkdir import &&
+	cd import &&
+	echo initial > file &&
+	svn import -m 'initial' . $svnrepo &&
+	cd .. &&
+	echo initial > file &&
+	git update-index --add file &&
+	git commit -a -m 'initial'
+	"
+test_expect_success 'commit change from svn side' "
+	svn co $svnrepo t.svn &&
+	cd t.svn &&
+	echo second line from svn >> file &&
+	svn commit -m 'second line from svn' &&
+	cd .. &&
+	rm -rf t.svn
+	"
+
+test_expect_failure 'commit conflicting change from git' "
+	echo second line from git >> file &&
+	git commit -a -m 'second line from git' &&
+	git-svn commit-diff -r1 HEAD~1 HEAD $svnrepo
+	" || true
+
+test_expect_success 'commit complementing change from git' "
+	git reset --hard HEAD~1 &&
+	echo second line from svn >> file &&
+	git commit -a -m 'second line from svn' &&
+	echo third line from git >> file &&
+	git commit -a -m 'third line from git' &&
+	git-svn commit-diff -r2 HEAD~1 HEAD $svnrepo
+	"
+
+test_expect_failure 'dcommit fails to commit because of conflict' "
+	git-svn init $svnrepo &&
+	git-svn fetch &&
+	git reset --hard refs/remotes/git-svn &&
+	svn co $svnrepo t.svn &&
+	cd t.svn &&
+	echo fourth line from svn >> file &&
+	svn commit -m 'fourth line from svn' &&
+	cd .. &&
+	rm -rf t.svn &&
+	echo 'fourth line from git' >> file &&
+	git commit -a -m 'fourth line from git' &&
+	git-svn dcommit
+	" || true
+
+test_expect_success 'dcommit does the svn equivalent of an index merge' "
+	git reset --hard refs/remotes/git-svn &&
+	echo 'index merge' > file2 &&
+	git update-index --add file2 &&
+	git commit -a -m 'index merge' &&
+	echo 'more changes' >> file2 &&
+	git update-index file2 &&
+	git commit -a -m 'more changes' &&
+	git-svn dcommit
+	"
+
+test_done