NameError: uninitialized constant Mail::Parsers::ContentTypeParser

[hiattp]

Just saw this error in our Rails 4.2.2 app running mail 2.6.3 on ruby 2.0.0. Any suggestions on how to track it down? Thanks!

[claudiofullscreen]

Me too! Here's the backtrace from Honeybadger. I hope it helps:

NameError: uninitialized constant Mail::Parsers::ContentTypeParser

Full Backtrace

content_type_element.rb  8  initialize(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/elements/content_type_element.rb:8:in `initialize'
content_type_field.rb  49  new(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:49:in `new'
content_type_field.rb  49  rescue in attempt_to_clean(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:49:in `rescue in attempt_to_clean'
content_type_field.rb  46  attempt_to_clean(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:46:in `attempt_to_clean'
content_type_field.rb  40  rescue in element(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:40:in `rescue in element'
content_type_field.rb  37  element(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:37:in `element'
content_type_field.rb  32  parse(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:32:in `parse'
content_type_field.rb  24  initialize(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:24:in `initialize'
field.rb  239  new(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/field.rb:239:in `new'
field.rb  239  new_field(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/field.rb:239:in `new_field'
field.rb  228  create_field(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/field.rb:228:in `create_field'
field.rb  141  field(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/field.rb:141:in `field'
field.rb  189  method_missing(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/field.rb:189:in `method_missing'
message.rb  1196  default(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/message.rb:1196:in `default'
message.rb  594  content_type(...)
[GEM_ROOT]/gems/mail-2.6.3/lib/mail/message.rb:594:in `content_type'
base.rb  871  set_content_type(...)
[GEM_ROOT]/gems/actionmailer-4.2.4/lib/action_mailer/base.rb:871:in `set_content_type'
base.rb  835  mail(...)

[jeremy]

Could you do some troubleshooting in console or a debugger to diagnose what's happening?

[claudiofullscreen]

Unfortunately I was not able to replicate the error.
Only happened that day three times… and then the same code worked as before.

The only hint that I have is that the title of the email includes an emoji.
It still does, and the same code now works… I just wonder if that was the case for @hiattp too.

I'll update this ticket in case I'm able to replicate the error in the future.

[hiattp]

We don't have emojis. Unfortunately this will be a hard one to track down in the console. It seems related to rails autoloading and is sporadic, so probably depends on the order in which things run on a new process. Will try to pin it down if we see another case

[jeremy]

Thanks!

[scottwater]

I have seen this off and on over the last couple of weeks (Rails 4.2.1), but I have not been able to track it down. First time it popped up was when we made a switch to Ruby 2.2.3.

[BrentWheeldon]

We are also sporadically seeing this, but for Mail::Parsers::AddressStruct. We also recently updated to Ruby 2.2.3.

[stephankaag]

Same issue overhere

-> NameError: uninitialized constant Mail::Parsers::ContentTypeParser
mail-2.6.3/lib/mail/elements/content_type_element.rb:8→ initialize
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ new
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ rescue in attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:46→ attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:40→ rescue in element
mail-2.6.3/lib/mail/fields/content_type_field.rb:37→ element
mail-2.6.3/lib/mail/fields/content_type_field.rb:32→ parse
mail-2.6.3/lib/mail/fields/content_type_field.rb:24→ initialize
mail-2.6.3/lib/mail/field.rb:239→ new
mail-2.6.3/lib/mail/field.rb:239→ new_field
mail-2.6.3/lib/mail/field.rb:228→ create_field
mail-2.6.3/lib/mail/field.rb:167→ update
mail-2.6.3/lib/mail/header.rb:174→ []=
mail-2.6.3/lib/mail/message.rb:598→ content_type=    

[PikachuEXE]

I got the same error too, but backtrace is different:
The most strange thing is that it only happens sometimes, can't be sure how to reproduce it

mail-2.6.3/lib/mail/elements/content_type_element.rb:8→ initialize
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ new
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ rescue in attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:46→ attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:40→ rescue in element
mail-2.6.3/lib/mail/fields/content_type_field.rb:37→ element
mail-2.6.3/lib/mail/fields/content_type_field.rb:32→ parse
mail-2.6.3/lib/mail/fields/content_type_field.rb:24→ initialize
mail-2.6.3/lib/mail/field.rb:239→ new
mail-2.6.3/lib/mail/field.rb:239→ new_field
mail-2.6.3/lib/mail/field.rb:228→ create_field
mail-2.6.3/lib/mail/field.rb:141→ field
mail-2.6.3/lib/mail/field.rb:189→ method_missing
mail-2.6.3/lib/mail/message.rb:1196→ default
mail-2.6.3/lib/mail/message.rb:594→ content_type
actionmailer-4.1.13/lib/action_mailer/base.rb:831→ set_content_type
actionmailer-4.1.13/lib/action_mailer/base.rb:795→ mail
mandriller-0.2.0/lib/mandriller/base.rb:80→ mail

[airimie]

We got this error a few times now. We are using sidekiq to send emails and sendgrid to deliver.

NameError: uninitialized constant Mail::Parsers::ContentTypeParser

/gems/mail-2.6.3/lib/mail/elements/content_type_element.rb:8 in initialize
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:49 in new
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:49 in rescue in attempt_to_clean
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:46 in attempt_to_clean
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:40 in rescue in element
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:37 in element
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:32 in parse
/gems/mail-2.6.3/lib/mail/fields/content_type_field.rb:24 in initialize
/gems/mail-2.6.3/lib/mail/field.rb:239 in new
/gems/mail-2.6.3/lib/mail/field.rb:239 in new_field
/gems/mail-2.6.3/lib/mail/field.rb:228 in create_field
/gems/mail-2.6.3/lib/mail/field.rb:167 in update
/gems/mail-2.6.3/lib/mail/header.rb:174 in []=
/gems/mail-2.6.3/lib/mail/message.rb:598 in content_type=
/gems/actionmailer-4.2.4/lib/action_mailer/base.rb:835 in mail
/gems/sendgrid-1.2.0/lib/sendgrid.rb:168 in mail
app/mailers/training_mailer.rb:7 in training_notification

[jamilbk]

Getting the same error here. Difficult to reproduce.

[airimie]

require 'mail/elements' is called after register_autoload :Parsers, "mail/parsers" (which probably it is not thread safe - looking at http://rxr.whitequark.org/mri/source/variable.c#1597 the only thing that method is doing is to add to a table the files to be loaded. This looks very much like the rails autoloading hell :) http://urbanautomaton.com/blog/2013/08/27/rails-autoloading-hell/ The solution will be to not use the autoloading at all.

[nburt]

Haven't been able to reproduce this either but getting this occasionally with various different mailers.

Backtrace:

mail-2.6.3/lib/mail/elements/content_type_element.rb:8→ initialize
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ new
mail-2.6.3/lib/mail/fields/content_type_field.rb:49→ rescue in attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:46→ attempt_to_clean
mail-2.6.3/lib/mail/fields/content_type_field.rb:40→ rescue in element
mail-2.6.3/lib/mail/fields/content_type_field.rb:37→ element
mail-2.6.3/lib/mail/fields/content_type_field.rb:32→ parse
mail-2.6.3/lib/mail/fields/content_type_field.rb:24→ initialize
mail-2.6.3/lib/mail/field.rb:239→ new
mail-2.6.3/lib/mail/field.rb:239→ new_field
mail-2.6.3/lib/mail/field.rb:228→ create_field
mail-2.6.3/lib/mail/field.rb:141→ field
mail-2.6.3/lib/mail/field.rb:189→ method_missing
mail-2.6.3/lib/mail/message.rb:1196→ default
mail-2.6.3/lib/mail/message.rb:594→ content_type
actionmailer-4.2.4/lib/action_mailer/base.rb:871→ set_content_type
actionmailer-4.2.4/lib/action_mailer/base.rb:835→ mail
roadie-rails-1.0.6/lib/roadie/rails/automatic.rb:5→ mail
app/mailers/testing_mailer.rb:10→ test_passed

[mirjoy]

I was able to resolve this issue by setting the content-type in my email:
content_type: "text/html"

[PikachuEXE]

I just add this workaround in an initializer:

require "mail/parsers/content_type_parser"

Already tested in staging for one day and no error pops up anymore
Now I will put this on production and see if the error happens again for the following few days