send-email: use "return;" not "return undef;" on error codepaths

All the callers of "ask", "extract_valid_address", and "validate_patch"
subroutines assign the return values from them to a single scalar:

$var = subr(...);

and "return undef;" in these subroutine can safely be turned into a
simpler "return;".  Doing so will also future-proof a new caller that
mistakenly does this:

@foo = ask(...);
if (@foo) { ... we got an answer ... } else { ... we did not ... }

Note that we leave "return undef;" in validate_address on purpose,
even though Perlcritic may complain.  The primary "return" site of
the function returns whatever is in the scalar variable $address, so
it is pointless to change only the other "return undef;" to "return".
The caller must be prepared to see an array with a single undef as
the return value from this subroutine anyway.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-send-email.perl b/git-send-email.perl
index be809e5b59394a4fd2f4f2b73cad6bac47a39600..79cc5bee9757c790f2a369d011ba2540f3c49332 100755 (executable)
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -711,7 +711,7 @@ sub ask {
                        }
                }
        }
-       return undef;
+       return;
 }
 
 my %broken_encoding;
@@ -833,7 +833,7 @@ sub extract_valid_address {
        # less robust/correct than the monster regexp in Email::Valid,
        # but still does a 99% job, and one less dependency
        return $1 if $address =~ /($local_part_regexp\@$domain_regexp)/;
-       return undef;
+       return;
 }
 
 sub extract_valid_address_or_die {
@@ -1484,7 +1484,7 @@ sub validate_patch {
                        return "$.: patch contains a line longer than 998 characters";
                }
        }
-       return undef;
+       return;
 }
 
 sub file_has_nonascii {