BMO/GPG.class.php function checkSig($sigfile) deems key invalid instead of fetching key

FreePPX version : 15.0.16.49 

I have tried to sign my own module with my own key, following instructions on the wiki (Requesting a Key to be Signed and Signing your own modules) but I still get “Module has been signed with an invalid key” in the “Module Admin” page and dashboard.

I found this :  

Line 691 in www/admin/libraries/BMO/GPG.class.php

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if (isset($out['status'][2]) && preg_match('/NO_PUBKEY (.+)/', $out['status'][2], $keyarr)) {

{{}}

{{}}This doesn't work for me. However,

if (isset($out['status'][3]) && preg_match('/NO_PUBKEY (.+)/', $out['status'][3], $keyarr)) {

does work.

$out['status'] is the status returned by the command (only the lines that are prefixed by "[GNUPG:]") :

{{}}

#sudo -u asterisk gpg --status-fd 3 --output - /opt/freepbx/www/admin/modules/droitappels/module.sig 

Here are the lines of interest :

[GNUPG:] PLAINTEXT 74 0
[GNUPG:] NEWSIG
[GNUPG:] ERRSIG D7669362454060A6 1 8 01 1586958176 9
[GNUPG:] NO_PUBKEY D7669362454060A6

NO_PUBKEY is in the 4th line, not the 3rd. Therefore "preg_match('/NO_PUBKEY (.+)/', $out['status'][2], $keyarr)" can never be true, and my key is never fetched from any keyserver at all.

You can see the proper way to check if the key needs to be fetched @ line 125 in www/admin/libraries/BMO/GPG.class.php :

{{}}

for($i=1;$i<count($out['status']);$i++) {
    if (strpos($out['status'][$i], "[GNUPG:] NO_PUBKEY") === 0) {
         // fetch key here 
    }
}

There may be a problem with my version of GnuPG (2.1.18) I wonder if anyone can show me what version they have and the result of the command line above.