bug#59444: ADVICE-ON-FAILURE sed syntax error

[Gregory Heytings <gregory@heytings.org>]

>> Again I tested this with (GNU) sed with --posix, and it gave the 
>> expected result.
>
> Then what we should learn from this is that GNU sed --posix cannot be 
> trusted blindly to reject non-POSIX features. This is unsurprising -- it 
> can be difficult to keep all extensions from leaking past the gate.
>

Do you know of any computer program that can be trusted blindly? ;-)

>> The reason I chose the former expression instead of the latter is 
>> because it's how I usually write such patterns.
>
> That doesn't answer the question. Why that roundabout way, rather than 
> the simpler direct approach?
>

I write such expressions that way because with that expression only the 
first matching block is printed.  Which is admittedly not important in 
this case, but habits being what they are...