QuietConsoleEmailBackend: prettier printing

message more clear, subject on a single line

bugsink/email_backends.py

@@ -1,3 +1,4 @@
+import re
 from django.core.mail.backends.console import EmailBackend as ConsoleEmailBackend
 
 
@@ -7,4 +8,18 @@ class QuietConsoleEmailBackend(ConsoleEmailBackend):
         msg = message.message()
         # self.stream.write("From: %s\n" % msg["From"])
         # self.stream.write("To: %s\n" % msg["To"])
-        self.stream.write("Mail not sent (no SMTP configured); Subject: %s\n" % msg["Subject"])
+        subject_header = msg["Subject"]
+
+        # Headers may contain newlines, RFC 2822 section 2.2.3 says:
+        #
+        # > The process of moving from this folded multiple-line representation
+        # > of a header field to its single line representation is called
+        # > "unfolding". Unfolding is accomplished by simply removing any CRLF
+        # > that is immediately followed by WSP. Each header field should be
+        # > treated in its unfolded form for further syntactic and semantic
+        # > evaluation.
+        #
+        # Remove those with a simple regex
+        # the regex says: match newline followed by whitespace, replace with just the matched whitespace:
+        subject = re.sub(r"\n(\s+)", (r"\1"), subject_header)
+        self.stream.write("Email is not set up, the following was not sent: %s\n" % subject)