[PATCH] Makefile: add allow-list for failures

[Florian Weimer]

* Andreas Schwab:

> On Feb 23 2026, Florian Weimer wrote:
>
>> * Martin Coufal:
>>
>>> Enable adding known failures to allowed-failures.txt and ignore failures
>>> in case they are in the list.  In case the allowed-failures.txt does not
>>> exist, all failures lead to a failed status as before.
>>>
>>> When the file is present, failures of listed tests are ignored and reported
>>> on stdout. If tests not in the allowed list fail, summarize-tests exits with
>>> status 1 and reports the failing tests.
>>>
>>> The expected format of allowed-failures.txt file is:
>>> <test_name> # <comment>
>>> ---
>>>  Makefile | 29 ++++++++++++++++++++++++++++-
>>>  1 file changed, 28 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Makefile b/Makefile
>>> index f81572c20a..f7a993f15b 100644
>>> --- a/Makefile
>>> +++ b/Makefile
>>> @@ -594,7 +594,34 @@ define summarize-tests
>>>  @grep -E '^[A-Z]+:' $(objpfx)$1 | grep -E -v '^(PASS|XFAIL):' || true
>>>  @echo "		=== Summary of results$2 ==="
>>>  @sed -e '/:.*/!d' -e 's/:.*//' < $(objpfx)$1 | sort | uniq -c
>>> -@! grep -E '^[A-Z]+:' $(objpfx)$1 | grep -E -q -v '^(X?PASS|XFAIL|UNSUPPORTED):'
>>> +@{ \
>>> +	grep -E '^[A-Z]+:' $(objpfx)$1 | \
>>> +	grep -E -v '^(X?PASS|XFAIL|UNSUPPORTED):' | \
>>> +	( \
>>> +	  if ! test -f $(..)allowed-failures.txt; then \
>>> +	    read -r _; exit $$(( $$? == 0 )); \
>>
>> Can we use bash-only constracts in Makefiles?
>
> Arithmetic expansion has been part of POSIX for more than 30 years.

Huh.  I wonder I why I still had to use expr in the 90s then.

Andreas, do you see any issues with Martin's patch?

Thanks,
Florian