Updating 'from' does not work

[bg]

I tried to extend Mail::Message to provide a default 'from' address by wrapping the old initialize with my own which would first call the old initialize, then set defaults, then instance_eval if a block was specified, and finally return self. All seemed to go well until I tried to override from= inside the block. This resulted in a message that, when delivered, raised this error:

NoMethodError: undefined method `addresses' for #<Mail::OptionalField:0xb72ab068>
    from /home/ben/.gem/ruby/1.8/gems/mail-1.3.0/lib/mail/field.rb:120:in `send'
    from /home/ben/.gem/ruby/1.8/gems/mail-1.3.0/lib/mail/field.rb:120:in `method_missing'
    from /home/ben/.gem/ruby/1.8/gems/mail-1.3.0/lib/mail/network/delivery_methods/smtp.rb:60:in `deliver!'
    from /home/ben/.gem/ruby/1.8/gems/mail-1.3.0/lib/mail/network/deliverable.rb:11:in `perform_delivery!'
    from /home/ben/.gem/ruby/1.8/gems/mail-1.3.0/lib/mail/message.rb:68:in `deliver!'
    from (irb):20
    from /home/ben/.gem/ruby/1.8/gems/treetop-1.4.2/lib/treetop/compiler/metagrammar.rb:415

First, I thought the problem might be that I now had multiple 'from' addresses and went to RFC 822 to see if that even made sense. Indeed, multiple authorship is valid, provided a single 'Sender' is specified, but when I inspected the message in irb, I did not find that multiple authorship had been set. Instead, I noticed something very odd about the message that results from trying to call 'from' twice, and that is that FromField is removed and replaced with an OptionalField with @name==:from (I have thrown some debug print statements in to see when we're doing an 'update' vs. 'create'):

>> mail.from='bg@dymaxion.ca'
[:create, "from", "bg@dymaxion.ca"]
=> "bg@dymaxion.ca"
>> mail.inspect
=> "#<Mail::Message:0xb72aff64 @header=#<Mail::Header:0xb72afd84 @fields=[#<Mail::Field:0xb72ade80 @field=#<Mail::FromField:0xb72addf4 @length=nil, @element=nil, @tree=nil, @value=\"bg@dymaxion.ca\", @name=\"From\">>], @raw_source=\"\">, @raw_source=\"\", @body=#<Mail::Body:0xb72afd5c @charset=\"US-ASCII\", @encoding=nil, @raw_source=\"\">>"
>> mail.from='barmstrong@dymaxion.ca'
[:update, "from", "barmstrong@dymaxion.ca"]
=> "barmstrong@dymaxion.ca"
>> mail.inspect
=> "#<Mail::Message:0xb72aff64 @header=#<Mail::Header:0xb72afd84 @fields=[#<Mail::Field:0xb72ade80 @field=#<Mail::OptionalField:0xb72ab068 @length=nil, @element=nil, @tree=nil, @value=\"barmstrong@dymaxion.ca\", @name=:from>>], @raw_source=\"\">, @raw_source=\"\", @body=#<Mail::Body:0xb72afd5c @charset=\"US-ASCII\", @encoding=nil, @raw_source=\"\">>"

Of course, to work around this problem, I could make users delete from after establishing the default to set a new value, but that's not very friendly, e.g.

>> mail=Mail.new
...
>> mail.from.value
"my@default.from.address"
>> mail.from nil
...
>> mail.from "some@new.address"

Ideally, what I would like mail.from= to do is to replace the old from address with the new. But failing that, I would like some way to specify a default 'from' address to use that, if no from address was specified by the time the message is delivered, would be used.

[mikel]

Good catch. I have fixed this in commit fa257d6..001a868. It will be included in the next gem release. It is a very simple fix if you want to patch your copy of mail.

[bg]

Thanks! Works for me.