git-svn: allow empty email-address using authors-prog and authors-file

The email address in --authors-file and --authors-prog can be empty but
git-svn translated it into a fictional email address in the form

	jondoe <jondoe@6aafaa21e0fb4338a68ab372a049893d>

containing the SVN repository UUID. Now git-svn behaves like git-commit:
If the email is *explicitly* set to the empty string using '<>', the
commit does not contain an email address, only the name:

	jondoe <>

Allowing to remove the email address *intentionally* prevents automatic
systems from sending emails to those fictional addresses and avoids
cluttering the log output with unnecessary stuff.

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Signed-off-by: Eric Wong <e@80x24.org>
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index b858374..d59379e 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -635,7 +635,8 @@
 
 -A<filename>::
 --authors-file=<filename>::
-	Syntax is compatible with the file used by 'git cvsimport':
+	Syntax is compatible with the file used by 'git cvsimport' but
+	an empty email address can be supplied with '<>':
 +
 ------------------------------------------------------------------------
 	loginname = Joe User <user@example.com>
@@ -654,8 +655,9 @@
 	If this option is specified, for each SVN committer name that
 	does not exist in the authors file, the given file is executed
 	with the committer name as the first argument.  The program is
-	expected to return a single line of the form "Name <email>",
-	which will be treated as if included in the authors file.
+	expected to return a single line of the form "Name <email>" or
+	"Name <>", which will be treated as if included in the authors
+	file.
 +
 Due to historical reasons a relative 'filename' is first searched
 relative to the current directory for 'init' and 'clone' and relative
diff --git a/perl/Git/SVN.pm b/perl/Git/SVN.pm
index 991a588..76b2965 100644
--- a/perl/Git/SVN.pm
+++ b/perl/Git/SVN.pm
@@ -1482,7 +1482,6 @@
 	}
 	if ($author =~ /^\s*(.+?)\s*<(.*)>\s*$/) {
 		my ($name, $email) = ($1, $2);
-		$email = undef if length $2 == 0;
 		return [$name, $email];
 	} else {
 		die "Author: $orig_author: $::_authors_prog returned "
@@ -2020,8 +2019,8 @@
 		remove_username($full_url);
 		$log_entry{metadata} = "$full_url\@$r $uuid";
 		$log_entry{svm_revision} = $r;
-		$email ||= "$author\@$uuid";
-		$commit_email ||= "$author\@$uuid";
+		$email = "$author\@$uuid" unless defined $email;
+		$commit_email = "$author\@$uuid" unless defined $commit_email;
 	} elsif ($self->use_svnsync_props) {
 		my $full_url = canonicalize_url(
 			add_path_to_url( $self->svnsync->{url}, $self->path )
@@ -2029,15 +2028,15 @@
 		remove_username($full_url);
 		my $uuid = $self->svnsync->{uuid};
 		$log_entry{metadata} = "$full_url\@$rev $uuid";
-		$email ||= "$author\@$uuid";
-		$commit_email ||= "$author\@$uuid";
+		$email = "$author\@$uuid" unless defined $email;
+		$commit_email = "$author\@$uuid" unless defined $commit_email;
 	} else {
 		my $url = $self->metadata_url;
 		remove_username($url);
 		my $uuid = $self->rewrite_uuid || $self->ra->get_uuid;
 		$log_entry{metadata} = "$url\@$rev " . $uuid;
-		$email ||= "$author\@" . $uuid;
-		$commit_email ||= "$author\@" . $uuid;
+		$email = "$author\@$uuid" unless defined $email;
+		$commit_email = "$author\@$uuid" unless defined $commit_email;
 	}
 	$log_entry{name} = $name;
 	$log_entry{email} = $email;
diff --git a/t/t9130-git-svn-authors-file.sh b/t/t9130-git-svn-authors-file.sh
index 4126481..6af6daf 100755
--- a/t/t9130-git-svn-authors-file.sh
+++ b/t/t9130-git-svn-authors-file.sh
@@ -108,6 +108,20 @@
 	)
 '
 
+cat >> svn-authors <<EOF
+ff = FFFFFFF FFFFFFF <>
+EOF
+
+test_expect_success 'authors-file imported user without email' '
+	svn_cmd mkdir -m aa/branches/ff --username ff "$svnrepo/aa/branches/ff" &&
+	(
+		cd aa-work &&
+		git svn fetch --authors-file=../svn-authors &&
+		git rev-list -1 --pretty=raw refs/remotes/origin/ff | \
+		  grep "^author FFFFFFF FFFFFFF <> "
+	)
+	'
+
 test_debug 'GIT_DIR=gitconfig.clone/.git git log'
 
 test_done
diff --git a/t/t9138-git-svn-authors-prog.sh b/t/t9138-git-svn-authors-prog.sh
index 7d7e9d4..e94d2a6 100755
--- a/t/t9138-git-svn-authors-prog.sh
+++ b/t/t9138-git-svn-authors-prog.sh
@@ -9,7 +9,9 @@
 
 write_script svn-authors-prog "$PERL_PATH" <<-\EOF
 	$_ = shift;
-	if (s/-sub$//)  {
+	if (s/-hermit//) {
+		print "$_ <>\n";
+	} elsif (s/-sub$//)  {
 		print "$_ <$_\@sub.example.com>\n";
 	} else {
 		print "$_ <$_\@example.com>\n";
@@ -68,6 +70,28 @@
 git --git-dir=x/.git config --unset svn.authorsfile
 git --git-dir=x/.git config --unset svn.authorsprog
 
+test_expect_success 'authors-prog imported user without email' '
+	svn mkdir -m gg --username gg-hermit "$svnrepo"/gg &&
+	(
+		cd x &&
+		git svn fetch --authors-prog=../svn-authors-prog &&
+		git rev-list -1 --pretty=raw refs/remotes/git-svn | \
+		  grep "^author gg <> "
+	)
+'
+
+test_expect_success 'imported without authors-prog and authors-file' '
+	svn mkdir -m hh --username hh "$svnrepo"/hh &&
+	(
+		uuid=$(svn info "$svnrepo" |
+			sed -n "s/^Repository UUID: //p") &&
+		cd x &&
+		git svn fetch &&
+		git rev-list -1 --pretty=raw refs/remotes/git-svn | \
+		  grep "^author hh <hh@$uuid> "
+	)
+'
+
 test_expect_success 'authors-prog handled special characters in username' '
 	svn mkdir -m bad --username "xyz; touch evil" "$svnrepo"/bad &&
 	(