Re: [PATCH 1/3] diff histogram: intern strings

On 18/11/2021 15:42, Jeff King wrote:

On Thu, Nov 18, 2021 at 04:35:48PM +0100, Johannes Schindelin wrote:

quoted

I think the really important thing to point out is that
`xdl_classify_record()` ensures that the `ha` attribute is different for
different text. AFAIR it even "linearizes" the `ha` values, i.e. they
won't be all over the place but start at 0 (or 1).

So no, I'm not worried about collisions. That would be a bug in
`xdl_classify_record()` and I think we would have caught this bug by now.

Ah, thanks for that explanation. That addresses my collision concern from
earlier in the thread completely.

Yes, thanks for clarifying I should have been clearer in my reply to 
Stolee. The reason I was waffling on about file sizes is that there can 
only be a collision if there are more than 2^32 unique lines. I think 
the minimum file size where that happens is just below 10GB when one 
side of the diff has 2^31 lines and the other has 2^31 + 1 lines and all 
the lines are unique.

Best Wishes

Phillip