Re: [PATCH] wip: Add forward-message-refs function.

On Thu, Aug 27, 2026 at 12:49 +0200, Alejandro Colomar via Mutt-dev wrote:

>> > There is code to support taggged messages, however the Mutt
>> > code (at least in the index and pager) on purpose removes References
>> > that are combined from two different "parents".
>>
>> Because that would be invalid. A mail thread is a tree; References:
>> describes a path through a tree, like a pathname of a file. In a tree, a
>> node can only have one parent. Message threads, being trees, do not allow
>> multiple parents.
>
>This is allowed.  In-Reply-To can have more than one message IDs.

You misunderstood. I said multiple parents invalidate References:, not 
In-Reply-To: Kevin mentioned References:; I replied about References:.

>Naturally, the 'References' field is used to form the path, and even
>though there are two "parents", the path shown in 'References' clearly
>tells which is the "closest" parent for printing the tree.
>
>Thus, I'd keep the 'References' of one of them (I'd use the longer one)
>when there are two parents, to help mutt(1) form a tree.

You give a single example, and generalize that to all possible cases. 
What if the two parents are siblings? What if neither parent is part of 
any thread? What if there are five parents, and none of them are 
related in any way?

References: can only express one path. When there are more than one, 
it's impossible to know which one is "most correct". References: should 
not exist for multiple parents.