send-email: specify content-type of --compose body

If the compose message contains non-ascii characters, then
we assume it is in utf-8 and include the appropriate MIME
headers. If the user has already included a MIME-Version
header, then we assume they know what they are doing and
don't add any headers.

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

git-send-email.perl

@@ -518,8 +518,22 @@ EOT
 	open(C,"<",$compose_filename)
 		or die "Failed to open $compose_filename : " . $!;
 
+	my $need_8bit_cte = file_has_nonascii($compose_filename);
+	my $in_body = 0;
 	while(<C>) {
 		next if m/^GIT: /;
+		if (!$in_body && /^\n$/) {
+			$in_body = 1;
+			if ($need_8bit_cte) {
+				print C2 "MIME-Version: 1.0\n",
+					 "Content-Type: text/plain; ",
+					   "charset=utf-8\n",
+					 "Content-Transfer-Encoding: 8bit\n";
+			}
+		}
+		if (!$in_body && /^MIME-Version:/i) {
+			$need_8bit_cte = 0;
+		}
 		print C2 $_;
 	}
 	close(C);
@@ -956,3 +970,13 @@ sub validate_patch {
 	}
 	return undef;
 }
+
+sub file_has_nonascii {
+	my $fn = shift;
+	open(my $fh, '<', $fn)
+		or die "unable to open $fn: $!\n";
+	while (my $line = <$fh>) {
+		return 1 if $line =~ /[^[:ascii:]]/;
+	}
+	return 0;
+}

t/t9001-send-email.sh

@@ -166,4 +166,48 @@ test_expect_success 'second message is patch' '
 	grep "Subject:.*Second" msgtxt2
 '
 
+test_expect_success '--compose adds MIME for utf8 body' '
+	clean_fake_sendmail &&
+	(echo "#!/bin/sh" &&
+	 echo "echo utf8 body: àéìöú >>\$1"
+	) >fake-editor-utf8 &&
+	chmod +x fake-editor-utf8 &&
+	echo y | \
+	  GIT_EDITOR=$(pwd)/fake-editor-utf8 \
+	  GIT_SEND_EMAIL_NOTTY=1 \
+	  git send-email \
+	  --compose --subject foo \
+	  --from="Example <nobody@example.com>" \
+	  --to=nobody@example.com \
+	  --smtp-server="$(pwd)/fake.sendmail" \
+	  $patches &&
+	grep "^utf8 body" msgtxt1 &&
+	grep "^Content-Type: text/plain; charset=utf-8" msgtxt1
+'
+
+test_expect_success '--compose respects user mime type' '
+	clean_fake_sendmail &&
+	(echo "#!/bin/sh" &&
+	 echo "(echo MIME-Version: 1.0"
+	 echo " echo Content-Type: text/plain\\; charset=iso-8859-1"
+	 echo " echo Content-Transfer-Encoding: 8bit"
+	 echo " echo Subject: foo"
+	 echo " echo "
+	 echo " echo utf8 body: àéìöú) >\$1"
+	) >fake-editor-utf8-mime &&
+	chmod +x fake-editor-utf8-mime &&
+	echo y | \
+	  GIT_EDITOR=$(pwd)/fake-editor-utf8-mime \
+	  GIT_SEND_EMAIL_NOTTY=1 \
+	  git send-email \
+	  --compose --subject foo \
+	  --from="Example <nobody@example.com>" \
+	  --to=nobody@example.com \
+	  --smtp-server="$(pwd)/fake.sendmail" \
+	  $patches &&
+	grep "^utf8 body" msgtxt1 &&
+	grep "^Content-Type: text/plain; charset=iso-8859-1" msgtxt1 &&
+	! grep "^Content-Type: text/plain; charset=utf-8" msgtxt1
+'
+
 test_done