fix: validate support_email format and handle parse errors in mailer (#13958)

## Description

ConversationReplyMailer#parse_email calls
Mail::Address.new(email_string).address without error handling. When an
account's support_email contains a non-email string (e.g., "Smith
Smith"), the mail gem raises Mail::Field::IncompleteParseError, crashing
conversation transcript emails.

This has caused 1,056 errors on Sentry (EXTERNAL-CHATINC-JX) since Feb
25, all from a single account that has a name stored in the
support_email field instead of a valid email address.

Closes
https://linear.app/chatwoot/issue/CW-6687/mailfieldincompleteparseerror-mailaddresslist-can-not-parse-orsmith

## Type of change

Please delete options that are not relevant.

- [ ] Bug fix (non-breaking change which fixes an issue)


## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Vishnu Narayanan <iamwishnu@gmail.com>

app/builders/email/base_builder.rb

@@ -1,4 +1,6 @@
 class Email::BaseBuilder
+  include EmailAddressParseable
+
   pattr_initialize [:inbox!]
 
   private
@@ -47,8 +49,4 @@ class Email::BaseBuilder
     # can save it in the format "Name <email@domain.com>"
     parse_email(account.support_email)
   end
-
-  def parse_email(email_string)
-    Mail::Address.new(email_string).address
-  end
 end

app/mailers/conversation_reply_mailer.rb

@@ -5,6 +5,7 @@ class ConversationReplyMailer < ApplicationMailer
 
   include ConversationReplyMailerHelper
   include ReferencesHeaderBuilder
+  include EmailAddressParseable
   default from: ENV.fetch('MAILER_SENDER_EMAIL', 'Chatwoot <accounts@chatwoot.com>')
   layout :choose_layout
 
@@ -139,10 +140,6 @@ class ConversationReplyMailer < ApplicationMailer
     sender_name(@channel.email)
   end
 
-  def parse_email(email_string)
-    Mail::Address.new(email_string).address
-  end
-
   def inbox_from_email_address
     return @inbox.email_address if @inbox.email_address
 

app/models/account.rb

@@ -30,50 +30,7 @@ class Account < ApplicationRecord
   include CacheKeys
   include CaptainFeaturable
   include AccountEmailRateLimitable
-
-  SETTINGS_PARAMS_SCHEMA = {
-    'type': 'object',
-    'properties':
-      {
-        'auto_resolve_after': { 'type': %w[integer null], 'minimum': 10, 'maximum': 1_439_856 },
-        'auto_resolve_message': { 'type': %w[string null] },
-        'auto_resolve_ignore_waiting': { 'type': %w[boolean null] },
-        'audio_transcriptions': { 'type': %w[boolean null] },
-        'auto_resolve_label': { 'type': %w[string null] },
-        'keep_pending_on_bot_failure': { 'type': %w[boolean null] },
-        'captain_auto_resolve_mode': { 'type': %w[string null], 'enum': ['evaluated', 'legacy', 'disabled', nil] },
-        'conversation_required_attributes': {
-          'type': %w[array null],
-          'items': { 'type': 'string' }
-        },
-        'captain_models': {
-          'type': %w[object null],
-          'properties': {
-            'editor': { 'type': %w[string null] },
-            'assistant': { 'type': %w[string null] },
-            'copilot': { 'type': %w[string null] },
-            'label_suggestion': { 'type': %w[string null] },
-            'audio_transcription': { 'type': %w[string null] },
-            'help_center_search': { 'type': %w[string null] }
-          },
-          'additionalProperties': false
-        },
-        'captain_features': {
-          'type': %w[object null],
-          'properties': {
-            'editor': { 'type': %w[boolean null] },
-            'assistant': { 'type': %w[boolean null] },
-            'copilot': { 'type': %w[boolean null] },
-            'label_suggestion': { 'type': %w[boolean null] },
-            'audio_transcription': { 'type': %w[boolean null] },
-            'help_center_search': { 'type': %w[boolean null] }
-          },
-          'additionalProperties': false
-        }
-      },
-    'required': [],
-    'additionalProperties': true
-  }.to_json.freeze
+  include AccountSettingsSchema
 
   DEFAULT_QUERY_SETTING = {
     flag_query_mode: :bit_operator,
@@ -86,6 +43,7 @@ class Account < ApplicationRecord
                  schema: SETTINGS_PARAMS_SCHEMA,
                  attribute_resolver: ->(record) { record.settings }
   validate :validate_reporting_timezone
+  validate :validate_support_email_format, if: :will_save_change_to_support_email?
 
   store_accessor :settings, :auto_resolve_after, :auto_resolve_message, :auto_resolve_ignore_waiting
 
@@ -223,6 +181,16 @@ class Account < ApplicationRecord
     errors.add(:reporting_timezone, I18n.t('errors.account.reporting_timezone.invalid'))
   end
 
+  def validate_support_email_format
+    value = attributes['support_email']
+    return if value.blank?
+
+    parsed = Mail::Address.new(value).address
+    errors.add(:support_email, I18n.t('errors.account.support_email.invalid')) if parsed.blank?
+  rescue Mail::Field::ParseError, Mail::Field::IncompleteParseError
+    errors.add(:support_email, I18n.t('errors.account.support_email.invalid'))
+  end
+
   def remove_account_sequences
     ActiveRecord::Base.connection.exec_query("drop sequence IF EXISTS camp_dpid_seq_#{id}")
     ActiveRecord::Base.connection.exec_query("drop sequence IF EXISTS conv_dpid_seq_#{id}")

app/models/concerns/account_settings_schema.rb

@@ -0,0 +1,47 @@
+module AccountSettingsSchema
+  extend ActiveSupport::Concern
+
+  SETTINGS_PARAMS_SCHEMA = {
+    'type': 'object',
+    'properties':
+      {
+        'auto_resolve_after': { 'type': %w[integer null], 'minimum': 10, 'maximum': 1_439_856 },
+        'auto_resolve_message': { 'type': %w[string null] },
+        'auto_resolve_ignore_waiting': { 'type': %w[boolean null] },
+        'audio_transcriptions': { 'type': %w[boolean null] },
+        'auto_resolve_label': { 'type': %w[string null] },
+        'keep_pending_on_bot_failure': { 'type': %w[boolean null] },
+        'captain_auto_resolve_mode': { 'type': %w[string null], 'enum': ['evaluated', 'legacy', 'disabled', nil] },
+        'conversation_required_attributes': {
+          'type': %w[array null],
+          'items': { 'type': 'string' }
+        },
+        'captain_models': {
+          'type': %w[object null],
+          'properties': {
+            'editor': { 'type': %w[string null] },
+            'assistant': { 'type': %w[string null] },
+            'copilot': { 'type': %w[string null] },
+            'label_suggestion': { 'type': %w[string null] },
+            'audio_transcription': { 'type': %w[string null] },
+            'help_center_search': { 'type': %w[string null] }
+          },
+          'additionalProperties': false
+        },
+        'captain_features': {
+          'type': %w[object null],
+          'properties': {
+            'editor': { 'type': %w[boolean null] },
+            'assistant': { 'type': %w[boolean null] },
+            'copilot': { 'type': %w[boolean null] },
+            'label_suggestion': { 'type': %w[boolean null] },
+            'audio_transcription': { 'type': %w[boolean null] },
+            'help_center_search': { 'type': %w[boolean null] }
+          },
+          'additionalProperties': false
+        }
+      },
+    'required': [],
+    'additionalProperties': true
+  }.to_json.freeze
+end

app/models/concerns/email_address_parseable.rb

@@ -0,0 +1,15 @@
+module EmailAddressParseable
+  extend ActiveSupport::Concern
+
+  private
+
+  def parse_email(email_string)
+    Mail::Address.new(email_string).address.presence || default_sender_email_address
+  rescue Mail::Field::ParseError, Mail::Field::IncompleteParseError
+    default_sender_email_address
+  end
+
+  def default_sender_email_address
+    Mail::Address.new(ENV.fetch('MAILER_SENDER_EMAIL', 'accounts@chatwoot.com')).address
+  end
+end

config/locales/en.yml

@@ -51,6 +51,8 @@ en:
     account:
       reporting_timezone:
         invalid: is not a valid timezone
+      support_email:
+        invalid: is not a valid email address
     validations:
       presence: must not be blank
     webhook:

spec/models/account_spec.rb

@@ -256,6 +256,29 @@ RSpec.describe Account do
       end
     end
 
+    context 'when support_email is set' do
+      it 'allows a plain email address' do
+        account.support_email = 'support@example.com'
+        expect(account).to be_valid
+      end
+
+      it 'allows display-name format' do
+        account.support_email = 'Support Team <support@example.com>'
+        expect(account).to be_valid
+      end
+
+      it 'allows blank values' do
+        account.support_email = ''
+        expect(account).to be_valid
+      end
+
+      it 'rejects malformed strings with no email part' do
+        account.support_email = 'Smith Smith'
+        expect(account).not_to be_valid
+        expect(account.errors[:support_email]).to include(I18n.t('errors.account.support_email.invalid'))
+      end
+    end
+
     context 'when reporting_timezone is set' do
       it 'allows valid timezone names' do
         account.reporting_timezone = 'America/New_York'