Link: headers and %?

Link: headers and %?

[Jason Gunthorpe]

I'm not quite sure where to post this, but since it intersects with
lore.kernel.org, this seems like a reasonable place.

Many people have been using the Link: headers lately, yay, but I've
noticed that some message ID's have a % in them, and people who have
scripts generating Link happily create commits like this:

commit 3baf89abca196f6dcb7038fd5342fd6e82f3260c
[..]
    Link: https://lore.kernel.org/r/20200324022505.UiPPJZVXX%akpm@linux-foundation.org

But the URLs don't work. They give a 404 because the % is the URL
escape character. To make the URL work it should be changed to %25:

https://lore.kernel.org/r/20200324022505.UiPPJZVXX%25akpm@linux-foundation.org

This situation seems sub-optimal.

It actually seems we have a mixture as some people must already be
using scripts that solve this:

commit 060dc911501f6ee222569304f50962172a52b1d6
    Link: https://lore.kernel.org/lkml/201912212139.yptX8CsV%25lkp@intel.com/

Should we URL encode the Link headers when creating the commits, or
should lore somehow not un-escape /r/ paths? They seem like exclusive
options.

Maybe checkpatch should be complaining?

Jason