Re: [PATCH for-4.21] tools/tests: don't pass -E to sed

[Jan Beulich <jbeulich@suse.com>]

On 08.10.2025 16:30, Roger Pau Monné wrote:
> On Wed, Oct 08, 2025 at 11:47:05AM +0200, Jan Beulich wrote:
>> Even the 2018 edition of The Open Group Base Specifications Issue 7 [1]
>> doesn't name -E as a standard option; only Issue 8 [2] does. As there's
>> nothing "extended" about the expression used, simply drop the -E.
>>
>> [1] https://pubs.opengroup.org/onlinepubs/9699919799/
>> [2] https://pubs.opengroup.org/onlinepubs/9799919799/
>>
>> Fixes: cb50e4033717 ("test/pdx: add PDX compression unit tests")
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks.

>> ---
>> In principle the -e could be dropped too, for being redundant.
>>
>> Hitting the problem with an older sed pointed out another problem here as
>> well: The failed invocation left a 0-byte pdx.h, which upon re-invocation
>> of make was (obviously) deemed up-to-date, thus causing the build to fail
>> again (until the bad file was actually removed).
> 
> Hm, we could do something like:
> 
> sed -e '/^#[[:space:]]*include/d' <$< >$@ || $(RM) $@

As is that would hide failure of the sed invocation from make. I was first
thinking to sed into a temporary file, to then rename that file. But this
won't cover the more general case of the issue either. Meanwhile I think
that the Makefile itself should become a dependency of the of the target
header. That way, if the sed expression changes, the file will be rebuilt.
(Of course this still builds on an assumption, specifically that any
failure here would be dealt with by an adjustment to the rule. So possibly
we need a combination of both.)

Jan