PHP imap_reopen no error returned

I have a script that connects to a mailbox. I'd like to check if I can connect to a folder that does not exist, but imap_reopen does not return errors.

<?php
$imap_url = "{mybox.mail.box:143}";

$mbox = imap_open($imap_url, "Mylogin", "Mypassword");
if ($mbox == false) {
    echo "Opening mailbox failed\n";
}

$submbox = imap_listmailbox($mbox, $imap_url, "*");
if ($submbox == false) {
    echo "Listing sub-mailboxes failed\n";
}
else {
    foreach ($submbox as $name) {
        echo $name . PHP_EOL;
    }
}   

$test = imap_reopen($mbox, $imap_url . "INBOX.MBOX3") or die(implode(", ", imap_errors()));
if ($test == false) {
    echo "Opening submbox failed\n";
}

?>

Script output :

{mybox.mail.box:143}.INBOX
{mybox.mail.box:143}.INBOX.MBOX1
{mybox.mail.box:143}.INBOX.MBOX2
PHP Notice:  Unknown: Mailbox does not exist (errflg=2) in Unknown on line 0

Do you have an idea ?

Regards,

Stiti

Solution

Your statement ending with or die() is actually terminating execution before the if test against the return value in $test.

$test = imap_reopen($mbox, $imap_url . "INBOX.MBOX3") or die(implode(", ", imap_errors()));

// This code is never reached because of die()!
if ($test == false) {
    echo "Opening submbox failed\n";
}

So just remove the or die() expression and your if ($test == false) will be evaluated. I'll also use === here since it should return a true boolean:

// Call imap_reopen() without (or die())
$test = imap_reopen($mbox, $imap_url . "INBOX.MBOX3");
if ($test === false) {
    echo "Opening submbox failed\n";
}

You may alternatively use

if (!$test) {
    echo "Opening submbox failed\n";
}

Note about the PHP E_NOTICE emitted - if imap_reopen() emits that notice even when returning false, this is one instance in which you may want to use the @ operator for error suppression since you are correctly testing for errors in your if block.

// @ is not usually recommended but if imap_reopen()
// prints an E_NOTICE while still returning false you can
// suppress it with @. This is among the only times it's
// a good idea to use @ for error suppresssion
$test = @imap_reopen($mbox, $imap_url . "INBOX.MBOX3");
if (!$test) {...}

Addendum after testing:

Documentation on imap_reopen() is slim and ambiguous stating its return as:

Returns TRUE if the stream is reopened, FALSE otherwise.

Some testing seems to imply that opening a non-existent mailbox is not considered an error state for which it returns false. When opening a non-existent mailbox on an otherwise valid stream, imap_reopen() will still return true but populate an error in imap_errors().

So you may check count(imap_errors()) > 0 for errors after opening the faulty mailbox. Couple that with a true return check, in case imap_reopen() does return a true error state.

For example my testing produces results similar to:

$test = imap_reopen($mbox, $imap_url . "NOTEXIST");
var_dump($test);
// bool(true);
var_dump(imap_errors());                                                  array(1) {
  [0] =>
  string(28) "Mailbox doesn't exist: NOTEXIST"
}

You may work around this using logic to:

$test = @imap_reopen($mbox, $imap_url . "INBOX.MBOX3");
if (!$test) {
  // An error with the stream
}
// Returns true, but imap_errors() is populated
else if ($test && count(imap_errors()) > 0) {
  echo "Opening submbox failed\n";
  // Do something with imap_errors() if needed
  echo implode(',', imap_errors());
}
else {
  // Everything is fine -  the mailbox was opened
}

For what it's worth, imap_open() exhibits the same behavior. Successfully connecting and establishing the stream (your variable $mbox) is possible with a non-existent mailbox. The stream is created and valid, but imap_errors() will contain a message Mailbox doesn't exist: <mailbox>.