RE: [PATCH v4 3/4] perf jevents: Switch build to use jevents.py

David Laight
2022-06-15T10:45:01Z

From: Ian Rogers
> Sent: 15 June 2022 04:05
>
> Generate pmu-events.c using jevents.py rather than the binary built from
> jevents.c. Add a new config variable NO_JEVENTS that is set when there
> is no architecture json or an appropriate python interpreter isn't present.
> When NO_JEVENTS is defined the file pmu-events/empty-pmu-events.c is copied
> and used as the pmu-events.c file.
>
...
> + # jevents.py uses f-strings present in Python 3.6 released in Dec. 2016.
> + JEVENTS_PYTHON_GOOD := $(shell $(PYTHON) -c 'import sys;print("1" if(sys.version_info.major >= 3
> and sys.version_info.minor >= 6) else "0")')

You probably want a "2>/dev/null" in there.

I also think I remember seeing a `which python` in one of these patches.
'which' is a bourne shell script that is trying to emulate a csh builtin.
It can't actually work, and ISTR one of the distros might be
trying to remove it.
In a traditional bourne shell you should use `type python`, the posix
equivalent (which any shell written in the last 30 years out to get
right) is `command -V python`.
Both type and command have to be shell builtins.
Although I suspect some shells get command -V wrong.

David

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