ident: trim whitespace from default name/email

Usually these values get fed to fmt_ident, which will trim
any cruft anyway, but there are a few code paths which use
them directly. Let's clean them up for the benefit of those
callers. Furthermore, fmt_ident will look at the pre-trimmed
value and decide whether to invoke ERROR_ON_NO_NAME; this
check can be fooled by a name consisting only of spaces.

Note that we only bother to clean up when we are pulling the
information from gecos or from system files. Any other value
comes from a config file, where we will have cleaned up
accidental whitespace already.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ident.c

@@ -95,8 +95,10 @@ static void copy_email(const struct passwd *pw, struct strbuf *email)
 
 const char *ident_default_name(void)
 {
-	if (!git_default_name.len)
+	if (!git_default_name.len) {
 		copy_gecos(xgetpwuid_self(), &git_default_name);
+		strbuf_trim(&git_default_name);
+	}
 	return git_default_name.buf;
 }
 
@@ -110,6 +112,7 @@ const char *ident_default_email(void)
 			user_ident_explicitly_given |= IDENT_MAIL_GIVEN;
 		} else
 			copy_email(xgetpwuid_self(), &git_default_email);
+		strbuf_trim(&git_default_email);
 	}
 	return git_default_email.buf;
 }