Re: [PATCH v6 1/3] perf jevents: Name the metric and the file 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 and the file it came from,
> before either of them can happen.  The file matters because the tables are
> read through a worker pool in main(), outside the directory walk, so an
> exception there loses the name of the table on its way out.  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 the
>   reader already knows the cause.
> 
> - The output files are opened after the tables have been read, so a tree
>   that fails to parse leaves no half-written table behind.
> 
> 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/20261111150920.2383157-1-takano32@gmail.com?part=1