[libcamera-devel] [PATCH v10 4/7] Add Python bindings

[Tomi Valkeinen]

On 09/05/2022 23:56, Kieran Bingham wrote:

> I'd like to add the following here while / when merging:
> 
> ================================================================================
> 
> diff --git a/src/py/libcamera/pymain.cpp b/src/py/libcamera/pymain.cpp
> index c983da3a94f1..09646faacd5a 100644
> --- a/src/py/libcamera/pymain.cpp
> +++ b/src/py/libcamera/pymain.cpp
> @@ -17,6 +17,7 @@
>   #include <unistd.h>
> 
>   #include <libcamera/base/log.h>
> +
>   #include <libcamera/libcamera.h>
> 
>   #include <pybind11/functional.h>
> @@ -138,6 +139,14 @@ static void handleRequestCompleted(Request *req)
>   void init_pyenums(py::module &m);
>   void init_pyenums_generated(py::module &m);
> 
> +/*
> + * The python module is not expected to be directly compatible with our usual
> + * code style, and clang-format can't easily handle the specific styles used
> + * with chaining here. Disable clang-format for the remainder of this module.
> + */
> +
> +// clang-format off
> +
>   PYBIND11_MODULE(_libcamera, m)
>   {
>          init_pyenums(m);
> ================================================================================
> 
> Any objections, or modifications to the comment?

Looks good to me.

I'd really like to use clang-format, though. It almost looks to me that 
clang-format bugs here. E.g. first clang-format formats to this:

	pyCamera
		.def(
			"start", [](Camera &self, py::dict controls) {
				return 0;
			},
			py::arg("controls") = py::dict());

I have no idea why it wants to add the line feed after .def. But I 
remove the py::arg, and format:

	pyCamera
		.def(
			"start", [](Camera &self, py::dict controls) {
				return 0;
			});

So no change. Then I first manually remove the line feed, i.e. 
.def("start", ... and then format:

	pyCamera
		.def("start", [](Camera &self, py::dict controls) {
			return 0;
		});

Ta-da! Now it's fine. But now, adding back the py::arg, and format, it 
goes back to the first case.

I've been fighting with clang-format before, and I have never managed it 
to format the code quite properly. Looking at the formatted pymain.cpp, 
I see two issues: the first is the extra line split like above, the 
second is that it likes to create very long lines for lambdas. Neither 
of those look like intended usual libcamera coding style, but rather 
bugs or misconfigured rules.

  Tomi