rfc2822: Support unquoted @s in the display name

  - Some OpenPGP implementations generate user ids that look like:

      foo@bar.com <foo@bar.com>

    foo@bar.com is not a valid display-name, because the '@' needs to
    be quoted.

    Support this variant anyway.

2 files changed, 31 insertions, 8 deletions

diff --git a/rfc2822/src/grammar.lalrpop b/rfc2822/src/grammar.lalrpop
index 4f664c5c..208d3da2 100644
--- a/rfc2822/src/grammar.lalrpop
+++ b/rfc2822/src/grammar.lalrpop
@@ -247,13 +247,19 @@ atext_plus : String = {
 
 // The display-name in a name-addr production often includes a ., but
 // is not quoted.  The RFC even recommends supporting this variant.
-other_or_dot : String = {
+// Also some OpenPGP implementations create User IDs that look like:
+//
+//   foo@bar.com <foo@bar.com>
+//
+// That is, with an unquoted at!  Support that too.
+other_or_dot_or_at : String = {
     <a:OTHER> => a.to_string(),
     <d:DOT> => d.to_string(),
+    <a:AT> => a.to_string(),
 }
 
-atext_dot_plus : String = {
-    <a:other_or_dot+> => strings_flatten(a.into_iter(), ""),
+atext_dot_at_plus : String = {
+    <a:other_or_dot_or_at+> => strings_flatten(a.into_iter(), ""),
 }
 
 // atom            =       [CFWS] 1*atext [CFWS]
@@ -267,7 +273,7 @@ pub(crate) Atom : Vec<Component> = {
 }
 
 atom : Vec<Component> = {
-    <c1:CFWS?> <a:atext_dot_plus> <c2:CFWS?> =>
+    <c1:CFWS?> <a:atext_dot_at_plus> <c2:CFWS?> =>
         components_concat!(
             c1,
             Component::Text(a),
@@ -277,7 +283,7 @@ atom : Vec<Component> = {
 // See the phrase production for why this variant of the 'atom'
 // production exists, and why the 'CFWS?'es are not included.
 atom_prime : Component = {
-    <a:atext_dot_plus> => Component::Text(a),
+    <a:atext_dot_at_plus> => Component::Text(a),
 }
 
 // dot-atom        =       [CFWS] dot-atom-text [CFWS]
diff --git a/rfc2822/src/lib.rs b/rfc2822/src/lib.rs
index d956afb7..2edb8090 100644
--- a/rfc2822/src/lib.rs
+++ b/rfc2822/src/lib.rs
@@ -805,7 +805,7 @@ mod tests {
 
     // atom            =       [CFWS] 1*atext [CFWS]
     //
-    // Note: our atom parser also allows for dots.
+    // Note: our atom parser also allows for dots and ats.
     //
     // An atom is a sequence of characters.
     //
@@ -825,7 +825,7 @@ mod tests {
                   "!", "#", "$", "%", "&", "'", "*", "+", "-",
                    "/", "=", "?", "^", "_", "`", "{", "|", "}", "~",
                    // Extension:
-                   "."]
+                   ".", "@"]
             .into_iter()
         {
             c(s, Some(vec![Component::Text(s.to_string())]))
@@ -833,7 +833,7 @@ mod tests {
 
         for &s in ["\x02", " ",
                   "(", ")", "<", ">", "[", "]", ":", ";",
-                  "@", "\\", ",", "\""]
+                  "\\", ",", "\""]
             .into_iter()
         {
             c(s, None)
@@ -1518,6 +1518,22 @@ mod tests {
     }
 
     #[test]
+    fn display_name_parser() {
+        c!(grammar::DisplayNameParser::new(), Vec<Component>);
+
+        c("Willi Wonka",
+          Some(vec![ Component::Text("Willi Wonka".into()) ]));
+
+        // As an extention we unquoted dots.
+        c("Willi A. Wonka",
+          Some(vec![ Component::Text("Willi A. Wonka".into()) ]));
+
+        // As an extention we unquoted ats.
+        c("foo@example.org",
+          Some(vec![ Component::Text("foo@example.org".into()) ]));
+    }
+
+    #[test]
     fn name_addr_api() {
         fn c_(name: Option<&str>, comment: Option<&str>, email: Option<&str>)
         {
@@ -1545,6 +1561,7 @@ mod tests {
 
         c("Harold Hutchins", "(artist)", "harold.hutchins@captain-underpants.com");
         c("Mr. Meaner", "(Gym Teacher)", "kenny@jerome-horwitz.k12.us");
+        c("foo@bar.com", "display name with at", "foo@bar.com");
     }
 
     #[test]