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Date:   Sun, 8 Aug 2021 15:18:04 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Maciej Falkowski <maciej.falkowski9@gmail.com>
Cc:     natechancellor@gmail.com, ndesaulniers@google.com,
        masahiroy@kernel.org, michal.lkml@markovi.net, nhuck@google.com,
        clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] clang-tools: Print information when clang-tidy tool
 is missing
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References: <CAK7LNAS=tyS22vk1mO7uCuzZ=YuzgByzC4Aix9JwugdV3xpr-Q@mail.gmail.com>
 <20210807110116.7985-1-maciej.falkowski9@gmail.com>
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On Sat, Aug 07, 2021 at 01:01:16PM +0200, Maciej Falkowski wrote:
> When clang-tidy tool is missing in the system, the FileNotFoundError
> exception is raised in the program reporting a stack trace to the user:
> 
> $ ./scripts/clang-tools/run-clang-tools.py clang-tidy ./compile_commands.json
> multiprocessing.pool.RemoteTraceback:
> """
> Traceback (most recent call last):
>   File "/usr/lib64/python3.8/multiprocessing/pool.py", line 125, in worker
>     result = (True, func(*args, **kwds))
>   File "/usr/lib64/python3.8/multiprocessing/pool.py", line 48, in mapstar
>     return list(map(*args))
>   File "./scripts/clang-tools/run-clang-tools.py", line 54, in run_analysis
>     p = subprocess.run(["clang-tidy", "-p", args.path, checks, entry["file"]],
>   File "/usr/lib64/python3.8/subprocess.py", line 489, in run
>     with Popen(*popenargs, **kwargs) as process:
>   File "/usr/lib64/python3.8/subprocess.py", line 854, in __init__
>     self._execute_child(args, executable, preexec_fn, close_fds,
>   File "/usr/lib64/python3.8/subprocess.py", line 1702, in _execute_child
>     raise child_exception_type(errno_num, err_msg, err_filename)
> FileNotFoundError: [Errno 2] No such file or directory: 'clang-tidy'
> """
> 
> The patch adds more user-friendly information about missing tool:
> 
> $ ./scripts/clang-tools/run-clang-tools.py clang-tidy ./compile_commands.json
> Command 'clang-tidy' is missing in the system
> 
> Signed-off-by: Maciej Falkowski <maciej.falkowski9@gmail.com>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1342

LGTM, I think this is much better than the stacktrace output as above as
it is easier for someone who is not familiar with these scrips to act
on.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> Hi Masahiro,
> 
> Thank you for your feedback!
> I am sorry that I haven't replied for so long.
> 
> I agree with your point, based on this I would like
> to propose a second version of the patch.
> 
> changes in v2:
>  - Solution has changed from LBYL style to EAFP
> 
> Best regards,
> Maciej Falkowski
> ---
>  scripts/clang-tools/run-clang-tools.py | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
> index fa7655c7cec0..27ebe2f2069a 100755
> --- a/scripts/clang-tools/run-clang-tools.py
> +++ b/scripts/clang-tools/run-clang-tools.py
> @@ -67,7 +67,14 @@ def main():
>      # Read JSON data into the datastore variable
>      with open(args.path, "r") as f:
>          datastore = json.load(f)
> -        pool.map(run_analysis, datastore)
> +        try:
> +            pool.map(run_analysis, datastore)
> +        except FileNotFoundError as err:
> +            if err.filename == 'clang-tidy':
> +                print("Command 'clang-tidy' is missing in the system", file=sys.stderr)
> +                sys.exit(127)
> +            else:
> +                raise err
>  
>  
>  if __name__ == "__main__":
> -- 
> 2.26.3