Support » Developing with WordPress » wp_mail() hiding recipient errors

  • I wanted to run this by someone before possibly opening a bug…

    After spending some time looking at why some mail-tags that allow replacement of from/to/and other headers in Contact Form 7 were not working (but not throwing an error), I started adding a bunch of debug statements in CF7. Everything looked fine, and where it called wp_mail(), there was no error.

    I then moved on to adding more debug stuff in wp-includes/pluggable.php.

    I followed things down to around line 260 where individual headers are parsed, and then down to line 303 where the reply-to is added. My debugging showed me that even though I was in that block within the switch statement, my “reply-to” was not being added. I was however able to see that I had the formatting wrong – there were multiple recipients, and I had “<,>” which got chunked into two addresses, “<” and “>”, neither of which passed PHPMailer’s validation.

    My thought is that if there’s an error in adding any of these addresses, wp_mail() should pass it on up the chain. The whole routine is wrapped in “try/catch”, but nothing is done with the error.

    Is this perhaps considered a bug in that end users of anything that calls “wp_mail()” (core, plugins) would spend an inordinate amount of time tracking down why mail is not sending… Thoughts?

    I also elaborated on this in the CF7 forum (, if that’s at all helpful, but to be clear, I’m NOT asking about plugin help, just wp_mail() itself and error handling…

Viewing 3 replies - 1 through 3 (of 3 total)
  • Moderator bcworkz


    Is this failing to send the message, or just failing to add poorly formatted Reply-To: addresses and sending anyway? If the message fails to send, false ought to be returned so the caller can do something else. But if the message is sent anyway, I don’t see address rejection as a reason to return an error.

    So maybe not a “bug” per se, but I do agree that doing nothing is poor behavior. The address rejection is handled at line 414 with continue;, meaning it’s ignored. We ought to do more than that, but I don’t think returning an error is appropriate. At least log a warning message or something. This is a pluggable function, so we’re free to add whatever process we want ahead of continue;.

    It would be nice to have an action hook inserted there so we could add in an exception handler without having to plug in an entire replacement function.

    Thread Starter sporkme


    Sorry I drifted away from this one…

    Yes, the message is sent, but is missing the headers.

    Personally, even just something, anything that would show up with debug enabled would be great. The error I tracked down ended up being really simple, but was nearly impossible to find by digging in logs and adding extra debugging in the plugin. I mean, maybe even displaying the error in all cases is worth something? If a user is expecting certain parameters to be set for the mail message and those are not being set do to a syntax problem, it seems like telling them is generally a good thing?

    PHPMailer does give a very nice and verbose answer when you screw up:

    in wp_mail() - address checker, adding reply-to as addr and name
    <strong>Invalid address:  (Reply-To): <</strong><br />
    in wp_mail() - before switch() on address_header
    in wp_mail() - address checker, adding reply-to as addr and name>
    <strong>Invalid address:  (Reply-To):></strong><br />
    Moderator bcworkz


    I could see returning a status code instead of a boolean. 0 for complete failure, xFF for normal completion, something in between for sent but errors were encountered.

    The simplest change would be to add a filter before the line 414 continue; so we can easily implement our own solution if there’s a PHPmailer exception.

Viewing 3 replies - 1 through 3 (of 3 total)
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