Re: nnmail-split-header-length-limit is EVIL!

[Dale Hagglund <rdh@best.com>]

Lars Magne Ingebrigtsen <larsi@gnus.org> writes:

> Oh, I had forgotten that.  Yes, there were two problems with the
> long lines -- the regexp could either overflow, or it could just
> take forever to run.  I've now reverted to removing the lines again.

This slightly crazy idea just occurred to me.  Say the max header
limit is 500, and some particular header line is, say, 1700 bytes.

What about matching the line against the split regexps in *overlapping
substrings* of at most 500 bytes each?  Each substring overlaps the
end of the previous chunk by, for example, 100 bytes.

You'd have to have some code to combine the split-results from each
substring, but that shouldn't be so hard.

I can't think that split strings depend in practice on matching a
substring longer than 100 bytes, but the ovelap amount could be
controlled by a variable as well.  Naturally, this whole slightly
weird behaviour should probably be controlled by yet another variable.

This might allow gnus to handle arbitrarily long header lines in a
more-or-less natural fashion without falling victim to the odd
pathological regular expression.

Is there something stupid I'm missing here?  Does anyone use split
regexps that would fail to work properly in this scheme?

Dale.