Re: [PATCH] scripts: run-clang-tools: add file filtering option

["Théo Lebrun" <theo.lebrun@bootlin.com>]

Hello Nathan,

On Sat Aug 3, 2024 at 12:35 AM CEST, Nathan Chancellor wrote:
> First of all, apologies that it has taken me so long to review this!

No worries, there is no rush!

> On Thu, Jul 04, 2024 at 11:28:21AM +0200, Théo Lebrun wrote:
> > Add file filtering feature. We take zero or more filters at the end as
> > positional arguments. If none are given, the default behavior is kept
> > and we run the tool on all files in the datastore. Else, files must
> > match one or more filter to be analysed.
> > 
> > The below command runs clang-tidy on drivers/clk/clk.c and all C files
> > inside drivers/reset/.
> > 
> >     ./scripts/clang-tools/run-clang-tools.py clang-tidy \
> >         compile_commands.json \
> >         'drivers/clk/clk.c' 'drivers/reset/*'
> > 
> > The Python fnmatch builtin module is used. Matching is case-insensitive.
> > See its documentation for allowed syntax:
> > https://docs.python.org/3/library/fnmatch.html
> > 
> > Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
> > ---
> > Currently, all files in the datastore are analysed. This is not
> > practical for grabbing errors in a subsystem, or relative to a patch
> > series. Add a file filtering feature with wildcard support.
>
> Sure, I think this is totally reasonable. In fact, I think some of this
> could be added to the commit message as further existence for this
> feature.

Indeed, it can be added to the commit message directly.

> The change itself looks good to me for the most part, I have some
> questions below just for my own understanding.
>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
>
> One further question/comment now: Have you considered a way to
> integrate this into Kbuild with the clang-tidy and clang-analyzer
> commands? I don't think it is strictly necessary for the acceptance of
> this patch but it might be nice to have some variable that users could
> provide to do this with their regular make command + the clang-tidy
> target? Not sure if Masahiro has further thoughts on that.

I have not as I am using this script by calling it directly.
It will either way be a separate patch.

>
> > Have a nice day,
> > Théo
> > ---
> >  scripts/clang-tools/run-clang-tools.py | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> > 
> > diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
> > index f31ffd09e1ea..b0b3a9c8cdec 100755
> > --- a/scripts/clang-tools/run-clang-tools.py
> > +++ b/scripts/clang-tools/run-clang-tools.py
> > @@ -10,6 +10,7 @@ compile_commands.json.
> >  """
> >  
> >  import argparse
> > +import fnmatch
> >  import json
> >  import multiprocessing
> >  import subprocess
> > @@ -32,6 +33,8 @@ def parse_arguments():
> >                          help=type_help)
> >      path_help = "Path to the compilation database to parse"
> >      parser.add_argument("path", type=str, help=path_help)
> > +    file_filter_help = "Optional Unix shell-style wildcard file filters"
> > +    parser.add_argument("file_filter", type=str, nargs="*", help=file_filter_help)
> >  
> >      checks_help = "Checks to pass to the analysis"
> >      parser.add_argument("-checks", type=str, default=None, help=checks_help)
> > @@ -48,6 +51,22 @@ def init(l, a):
> >      args = a
> >  
> >  
> > +def filter_entries(datastore, filters):
> > +    for entry in datastore:
> > +        if filters == []:
> > +            yield entry
> > +            continue
> > +
> > +        assert entry['file'].startswith(entry['directory'])
>
> What is the purpose of this assertion? Will it cause AssertionError
> under normal circumstances?

Just below we extract `filepath` from entry["file"] by removing at its
start the length of entry["directory"]. We expect entry["file"] to
start with entry["directory"], so we document that with an assertion.

If this assertion triggers, it means the line below would do something
weird and would silently break the program. Silently because `filepath`
is used for pattern matching and is never displayed.

>
> > +        # filepath is relative to the directory, to avoid matching on the absolute path
> > +        filepath = entry['file'][len(entry['directory']):].lstrip('/')

Regards,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com