filter-repo: parse mailmap entries with no email address

The mailmap format parsed by the "git shortlog" command allows for
matching mailmap entries with no email address. This is admittedly an
edge case, because most Git commits will have an email address
associated with them as well as a name, but technically the address
isn't required, and "git shortlog" accommodates that in its mailmap
format. This commit teaches git-filter-repo to do the same thing.

Signed-off-by: Karl Lenz <xorangekiller@gmail.com>

git-filter-repo

@@ -267,7 +267,7 @@ class MailmapInfo(object):
     self._parse_file(filename)
 
   def _parse_file(self, filename):
-    name_and_email_re = re.compile(br'(.*?)\s*<([^>]+)>\s*')
+    name_and_email_re = re.compile(br'(.*?)\s*<([^>]*)>\s*')
     comment_re = re.compile(br'\s*#.*')
     if not os.access(filename, os.R_OK):
       raise SystemExit(_("Cannot read %s") % decode(filename))

t/t9390-filter-repo.sh

@@ -48,6 +48,7 @@ filter_testcase degenerate degenerate-keepme   --path moduleA/keepme
 filter_testcase degenerate degenerate-moduleA  --path moduleA
 filter_testcase degenerate degenerate-globme   --path-glob *me
 filter_testcase unusual unusual-filtered --path ''
+filter_testcase unusual unusual-mailmap  --mailmap ../t9390/sample-mailmap
 
 test_expect_success 'setup path_rename' '
 	test_create_repo path_rename &&

t/t9390/sample-mailmap

@@ -4,3 +4,4 @@ Little 'ol Me <me@little.net>
 Little 'ol Me <me@little.net> Little O. Me
 Little 'ol Me <me@little.net> <me@fire.com>
 Little 'ol Me <me@little.net> Little Me <me@bigcompany.com>
+Little John <second@merry.men> little.john <>

t/t9390/unusual

@@ -28,7 +28,7 @@ from :2
 tag v1.0
 from :2
 original-oid 0000000000000000000000000000000000000003
-tagger Little John <second@merry.men> 1535229618 -0700
+tagger little.john <> 1535229618 -0700
 data 4
 v1.0
 

t/t9390/unusual-filtered

@@ -17,7 +17,7 @@ from :2
 
 tag v1.0
 from :2
-tagger Little John <second@merry.men> 1535229618 -0700
+tagger little.john <> 1535229618 -0700
 data 4
 v1.0
 done

t/t9390/unusual-mailmap

@@ -0,0 +1,23 @@
+feature done
+blob
+mark :1
+data 5
+hello
+reset refs/heads/develop
+commit refs/heads/develop
+mark :2
+author Srinivasa Ramanujan <fellow@cambridge.org> 1535228562 +0261
+committer Srinivasa Ramanujan <fellow@cambridge.org> 1535228562 +0261
+data 8
+Initial
+M 100644 :1 greeting
+
+reset refs/heads/master
+from :2
+
+tag v1.0
+from :2
+tagger Little John <second@merry.men> 1535229618 -0700
+data 4
+v1.0
+done