Re: [Nmh-workers] Limit of 27 messages sequences per folder

[Ken Hornstein]

>> I double-checked my earlier assertion, and it turns out I was correct.
>> The "extra" sequence(s) silently gets ignored upon read by older utilities
>> and will be deleted when the sequence file is updated.  Is that Something
>> Evil?  Depends on your perspective, I suppose.  I think it's behavior
>> I could live with.
>
>You got some way to ensure that the Unseen sequence is in the first 27? :)

I was curious about that, so I looked; the answer is "no".  I guess I
was thinking about the general Unix idea that you should give the user
enough rope to hang his-or-her-self if they so desire.

Let me ask a counter-question.  Given Norm's request, what is your
answer?  Do nothing?  Does that mean we cannot ever raise the sequence
limit?  We actually don't enforce this anywhere; if you compile on an
ILP64 system, you'll already have more than 27 sequences supported.
I don't know how common ILP64 systems are, though.  My point is that
we never really had any explicit guarantees as to what happens if you
have more than 27 sequences.  I admit that I don't have a great answer
for this situation.

Norm writes:
>> The attractiveness of Norm's suggestion is that it's literally a
>> one-line change.
>
>Not counting changing the man page for mark.

Hm.  You know, I just looked at that.  Turns out that this was a problem
already:

  Only a certain number of sequences may be defined for a given folder.
  This number is usually limited to 27 (11 on small systems).

Wow, THAT entry sure is dated.  16-bit ints!  Although I wonder if any
of those systems with 16-bit ints had NFS; seems unlikely.  But clearly
the "MH way" was to silently discard sequences that exceeded the
per-folder limit.  That doesn't mean that it should always be the way,
of course.

--Ken