Mail from reports promises not being sent on CFEngine Community 3.7.0

[Erik S]

CFEngine Community 3.5 and 3.6 (by default) sent mail for "reports" promises. This doesn't seem to be happening by default in 3.7.0, at least for my configuration.

My controls/3.7/def.cf looks something like:

      # Mail settings used by body executor control found in controls/cf_execd.cf
      "mailto" string => ifelse(isvariable("override_data_mailto"), "$(override_data_mailto)",
                               "orchestr...@mylist.fake"),
      meta => { "defvar" };

      "mailfrom" string => ifelse(isvariable("override_data_mailfrom"), "$(override_data_mailfrom)",
                                 "root@$(sys.fqhost)"),
      meta => { "defvar" };

      "smtpserver" string => ifelse(isvariable("override_data_smtpserver"), "$(override_data_smtpserver)",
                                   "localhost"),
      meta => { "defvar" };

When a "reports" promise is run, it's recorded via syslog. But it doesn't appear that cf_execd is even attempting to send mail.

Just for the sake of experimentation, I tried hardcoding values in controls/3.7/cf_execd.cf and putting the mail variable settings into the "any" class, then testing again - still no mail being sent.

A few facts about the situation:

• I'm able to send email using mailx(1) to the same address I have configured in def.cf.
• I have not created a def.json.
  
• During the times I would expect cf_execd to be submitting mail to the MTA, nothing appears in its (the MTA's) logs.

Has anyone experienced this and/or does anyone have suggestions for pinpointing the issue?