merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 15 insertions, 3 deletions

diff --git a/third_party/git/git-send-email.perl b/third_party/git/git-send-email.perl
index 5f92c89c1c..1f425c0809 100755
--- a/third_party/git/git-send-email.perl
+++ b/third_party/git/git-send-email.perl
@@ -250,6 +250,7 @@ my $chain_reply_to = 0;
 my $use_xmailer = 1;
 my $validate = 1;
 my $target_xfer_encoding = 'auto';
+my $forbid_sendmail_variables = 1;
 
 my %config_bool_settings = (
     "thread" => \$thread,
@@ -263,6 +264,7 @@ my %config_bool_settings = (
     "multiedit" => \$multiedit,
     "annotate" => \$annotate,
     "xmailer" => \$use_xmailer,
+    "forbidsendmailvariables" => \$forbid_sendmail_variables,
 );
 
 my %config_settings = (
@@ -478,6 +480,12 @@ unless ($rc) {
     usage();
 }
 
+if ($forbid_sendmail_variables && (scalar Git::config_regexp("^sendmail[.]")) != 0) {
+	die __("fatal: found configuration options for 'sendmail'\n" .
+		"git-send-email is configured with the sendemail.* options - note the 'e'.\n" .
+		"Set sendemail.forbidSendmailVariables to false to disable this check.\n");
+}
+
 die __("Cannot run git format-patch from outside a repository\n")
 	if $format_patch and not $repo;
 
@@ -1228,7 +1236,7 @@ sub process_address_list {
 # domain name that corresponds the IP address in the HELO/EHLO
 # handshake. This is used to verify the connection and prevent
 # spammers from trying to hide their identity. If the DNS and IP don't
-# match, the receiveing MTA may deny the connection.
+# match, the receiving MTA may deny the connection.
 #
 # Here is a deny example of Net::SMTP with the default "localhost.localdomain"
 #
@@ -1699,10 +1707,14 @@ sub process_file {
 				$xfer_encoding = $1 if not defined $xfer_encoding;
 			}
 			elsif (/^In-Reply-To: (.*)/i) {
-				$in_reply_to = $1;
+				if (!$initial_in_reply_to || $thread) {
+					$in_reply_to = $1;
+				}
 			}
 			elsif (/^References: (.*)/i) {
-				$references = $1;
+				if (!$initial_in_reply_to || $thread) {
+					$references = $1;
+				}
 			}
 			elsif (!/^Date:\s/i && /^[-A-Za-z]+:\s+\S/) {
 				push @xh, $_;