Can't send "from" an email containing brackets

[ghiculescu]

We are seeing errors in production when sending email via Mailtrap where the from address includes brackets. For example

mail(from: "foo (bar) <[email protected]>")

Leads to this

I tried writing a failing test, I couldn't get it to crash, but it does fail:

diff --git a/spec/mailtrap/mail_spec.rb b/spec/mailtrap/mail_spec.rb
index 6bd5f88..301d545 100644
--- a/spec/mailtrap/mail_spec.rb
+++ b/spec/mailtrap/mail_spec.rb
@@ -13,7 +13,7 @@ RSpec.describe Mailtrap::Mail do
     let(:message) { Mail::Message.new(**message_params) }
     let(:message_params) do
       {
-        from: 'Mailtrap Test <[email protected]>',
+        from: 'Mailtrap (Test) <[email protected]>',
         to: 'To 1 <[email protected]>, [email protected]',
         cc: '[email protected], Cc 2 <[email protected]>',
         bcc: '[email protected], [email protected]',
@@ -23,7 +23,7 @@ RSpec.describe Mailtrap::Mail do
       }
     end

-    its(:from) { is_expected.to eq({ name: 'Mailtrap Test', email: '[email protected]' }) }
+    its(:from) { is_expected.to eq({ name: 'Mailtrap (Test)', email: '[email protected]' }) }
     its(:to) { is_expected.to eq([{ name: 'To 1', email: '[email protected]' }, { email: '[email protected]' }]) }
     its(:cc) { is_expected.to eq([{ email: '[email protected]' }, { name: 'Cc 2', email: '[email protected]' }]) }
     its(:bcc) { is_expected.to eq([{ email: '[email protected]' }, { email: '[email protected]' }]) }

So I suspect there's something wrong in the gem here, and maybe the test just isn't accurately replicating how Action Mailer works.

[leonid-shevtsov]

You should quote the display name if it contains parenthesis, they are a special character according to the RFC; the relevant part is:

display-name = phrase
phrase          =   1*word / obs-phrase
obs-phrase      =   word *(word / "." / CFWS)
word            =   atom / quoted-string
atom            =   [CFWS] 1*atext [CFWS]
atext           =   ALPHA / DIGIT /    ; Printable US-ASCII
                       "!" / "#" /        ;  characters not including
                       "$" / "%" /        ;  specials.  Used for atoms.
                       "&" / "'" /
                       "*" / "+" /
                       "-" / "/" /
                       "=" / "?" /
                       "^" / "_" /
                       "`" / "{" /
                       "|" / "}" /
                       "~"

Or you can use the email+name form, and I'm pretty sure we will quote it for you:

{ email: '[email protected]', name: 'Mailtrap (Test)' }

But I admit that stripping the parens is sketchy, will look into it.