Re: UTF-8 in glibc commit messages

[Paul Eggert <eggert@cs.ucla.edu>]

On 4/14/21 8:01 AM, Mike Frysinger wrote:
> can't we be proactive ?  let's go all-in on UTF-8.

A problem with "all-in" is that UTF-8 has weird characters that can mess 
things up. The commit message check was originally put in because 
someone copy-pasted U+2069 POP DIRECTIONAL ISOLATE into a commit message 
without realizing it. That invisible character breaks simple searches 
like 'grep -w'.

glibc's current check isn't quite right either, as it allows lines like 
this:

     Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

in which each "space" is actually U+00A0 NO-BREAK SPACE. Although that's 
valid ISO-8895-15, U+00A0 is another weird character that we arguably 
shouldn't allow as it can also mess up searches (it's even blacklisted 
in URLs by some browsers because of the potential for phishing).

It'd be better to come up with an exact list of acceptable Unicode 
characters (probably a set of categories with some exceptions). This 
would be better than the current approach which is either too-generous 
or (mostly) too-restrictive. But it'd be some work.