Fix email date format in non-English locales (#2928).2928-email

4 files changed, 67 insertions, 1 deletions

diff --git a/src/lib/email.cc b/src/lib/email.cc
index 2da57e257..a731501bc 100644
--- a/src/lib/email.cc
+++ b/src/lib/email.cc
@@ -24,6 +24,7 @@
 #include "email.h"
 #include "exceptions.h"
 #include "variant.h"
+#include <dcp/scope_guard.h>
 #include <curl/curl.h>
 #include <boost/algorithm/string.hpp>
 #include <boost/date_time/c_local_time_adjustor.hpp>
@@ -113,7 +114,11 @@ void
 Email::create(time_t time)
 {
 	char date_buffer[128];
-	strftime(date_buffer, sizeof(date_buffer), "%a, %d %b %Y %H:%M:%S ", localtime(&time));
+
+	auto english_locale = newlocale(LC_TIME_MASK, "C", 0);
+	DCPOMATIC_ASSERT(english_locale);
+	dcp::ScopeGuard sg = [english_locale]() { freelocale(english_locale); };
+	strftime_l(date_buffer, sizeof(date_buffer), "%a, %d %b %Y %H:%M:%S ", localtime(&time), english_locale);
 
 	auto const utc_time = boost::posix_time::second_clock::universal_time();
 	auto const local_time = boost::date_time::c_local_adjustor<boost::posix_time::ptime>::utc_to_local(utc_time);
diff --git a/src/lib/email.h b/src/lib/email.h
index 24f20956a..3f9cf1dd8 100644
--- a/src/lib/email.h
+++ b/src/lib/email.h
@@ -24,6 +24,9 @@
 #include <boost/scoped_array.hpp>
 
 
+struct email_date_format_test;
+
+
 class Email
 {
 public:
@@ -51,6 +54,7 @@ public:
 	static std::string address_list(std::vector<std::string> addresses);
 
 private:
+	friend struct ::email_date_format_test;
 
 	std::string fix (std::string s) const;
 	static std::string encode_rfc1342 (std::string subject);
diff --git a/test/email_test.cc b/test/email_test.cc
new file mode 100644
index 000000000..2c444de39
--- /dev/null
+++ b/test/email_test.cc
@@ -0,0 +1,56 @@
+/*
+    Copyright (C) 2025 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+
+#include "lib/email.h"
+#include <dcp/scope_guard.h>
+#include <boost/algorithm/string.hpp>
+#include <boost/test/unit_test.hpp>
+#include <iostream>
+#include <string>
+#include <vector>
+
+
+using std::string;
+using std::vector;
+
+
+/* Make sure email dates are always in English (per RFC 2822) */
+BOOST_AUTO_TEST_CASE(email_date_format_test)
+{
+	auto previous = setlocale(LC_TIME, nullptr);
+	dcp::ScopeGuard sg = [previous]() { setlocale(LC_TIME, previous); };
+
+	auto result = setlocale(LC_TIME, "de_DE.UTF8");
+	BOOST_REQUIRE(result);
+
+	Email email("bob@popcornwiththat.com", { "orders@popcorn.com" }, "Popcorn order", "Please send popcorn.");
+	email.create(0);
+
+	vector<string> lines;
+	boost::algorithm::split(lines, email.email(), boost::is_any_of("\n\r"));
+
+	for (auto line: lines) {
+		if (boost::starts_with(line, "Date: ")) {
+			BOOST_CHECK_EQUAL(line, "Date: Thu, 01 Jan 1970 01:00:00 +0100");
+		}
+	}
+}
+
diff --git a/test/wscript b/test/wscript
index 229330265..115121bde 100644
--- a/test/wscript
+++ b/test/wscript
@@ -80,6 +80,7 @@ def build(bld):
                  dcp_subtitle_test.cc
                  digest_test.cc
                  dkdm_recipient_list_test.cc
+                 email_test.cc
                  empty_caption_test.cc
                  empty_test.cc
                  encryption_test.cc