fix: handle invalid imap message id

When IMAPMessage.toDbMessage() encountered an invalid messageId it was
creating a DB Message without messageId. This leads for example to
TagMapper::tagMessage() to fail because it must not be called with a
null messageId.

This patch leverages the functionality to create a valid messageId in
case the messageId was missing completely. It now uses it as well for
invalid messageIds not accepted by Horde_Mail_Rfc822_Identification and
therefore not set by Message.setMessageId().

An example for an invalid messageId I encountered in my inbox is
Message-ID: <359f166ea1b402e793c0801834a9722a-support@aruba-studios.de
(The closing > bracket is missing).

Signed-off-by: Anna Larch <anna@nextcloud.com>

2 files changed, 13 insertions, 4 deletions

diff --git a/lib/Db/Message.php b/lib/Db/Message.php
index 1a62a5214..ee44b40fb 100644
--- a/lib/Db/Message.php
+++ b/lib/Db/Message.php
@@ -36,7 +36,7 @@ use function json_encode;
 /**
  * @method void setUid(int $uid)
  * @method int getUid()
- * @method string getMessageId()
+ * @method string|null getMessageId()
  * @method void setReferences(string $references)
  * @method string|null getReferences()
  * @method string|null getInReplyTo()
@@ -153,6 +153,12 @@ class Message extends Entity implements JsonSerializable {
 		$this->addType('updatedAt', 'integer');
 	}
 
+	/**
+	 * @param string|null $messageId
+	 *
+	 * Parses the message ID to see if it is a valid Horde_Mail_Rfc822_Identification
+	 * before setting it, or sets null if it is not valid.
+	 */
 	public function setMessageId(?string $messageId): void {
 		$this->setMessageIdFieldIfNotEmpty('messageId', $messageId);
 	}
diff --git a/lib/Model/IMAPMessage.php b/lib/Model/IMAPMessage.php
index b2d3fcddb..2406257b9 100644
--- a/lib/Model/IMAPMessage.php
+++ b/lib/Model/IMAPMessage.php
@@ -696,13 +696,16 @@ class IMAPMessage implements IMessage, JsonSerializable {
 		$msg = new Message();
 
 		$messageId = $this->getMessageId();
-		if (empty(trim($messageId))) {
-			// Sometimes the message ID is missing. Then we create one.
+		$msg->setMessageId($messageId);
+
+		// Sometimes the message ID is missing or invalid and therefore not set.
+		// Then we create one and set it.
+		if (empty(trim($msg->getMessageId()))) {
 			$messageId = self::generateMessageId();
+			$msg->setMessageId($messageId);
 		}
 
 		$msg->setUid($this->getUid());
-		$msg->setMessageId($messageId);
 		$msg->setRawReferences($this->getRawReferences());
 		$msg->setThreadRootId($messageId);
 		$msg->setInReplyTo($this->getRawInReplyTo());