Re: [PATCH 1/3] perf jevents: Name the metric when a MetricExpr is missing

[sashiko-bot@kernel.org]

> jevents.py reads each field it wants out of a JSON object by name, so a
> MetricExpr key that is missing or spelled another way leaves the object
> with a MetricName and no expression. Two different failures followed,
> neither of which named the metric: the rewrite in _read_json_events_impl()
> raised AttributeError on the None, and a metric that got that far reached
> print_pending_metrics(), whose assert fired on it.
> 
> Raise in the reader instead, naming the metric, before either of them can
> happen. The check is not inside the '-' test that decides whether a metric
> takes part in the rewrite: a name with a dash in it can lose its
> expression the same way.
> 
> Two smaller changes on the same path:
> 
> - An architecture standard table that does not parse now carries the
>    reason in its message ("Failure processing '<file>' in '<dir>':
>    <cause>").  The traceback used to end with the file name alone, and
>    only the chained exception said why.
> 
> - A table that does not parse is reported on stderr with a "jevents:
>    error:" prefix instead of on stdout, where it was mixed with the
>    generated output.
> 
> And the output file is opened after the tables have been read, and not by
> argparse, so a build that fails while reading them leaves a file the
> caller named as it was instead of truncating it to the header.
> 
> Signed-off-by: TAKANO Mitsuhiro <takano32@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261110222250.1864777-1-takano32@gmail.com?part=1