Expose argument names to Python bindings

[dbaston]

Feature description

Most Python functions currently have a signature (*args,**kwargs). This is a result of the SWIG feature compactdefaultargs, which is both turned on globally in several .i files using %feature("compactdefaultargs"), and turned on automatically by SWIG whenever %feature("kwargs") is used (some 400 instances). Many invocations of %feature("kwargs") are enabled only for certain languages, for reasons that are not always clear.

Full signatures (such as def OpenEx(utf8_path, nOpenFlags=0, allowed_drivers=None, open_options=None, sibling_files=None)) can be obtained by disabling compactdefaultargs using %feature("compactdefaultargs", "") and re-enabling it only for the handful of functions that require it for overload resolution. (SWIG warnings indicate which functions are affected.)

Additional context

No response

[geographika]

An advantage of having the parameter names available in the Python bindings will be that IDEs will be able to show the parameters interactively, as the IDLE example below.

[sidhansu10]

Hi @dbaston, I’d like to work on this issue and submit a PR to expose argument names in the Python bindings. I’m familiar with Python and recently made a documentation contribution to GDAL. Please let me know if that sounds good.

[dbaston]

@sidhansu10 that sounds great! I would start with a small PR that changes a few functions and adds a test that verifies that they have named arguments. We also need to be careful that we don't accidentally break anything in the Java or C# bindings...not sure the best way to do that.

[sidhansu10]

Thanks @dbaston! That makes sense. I’ll start with a small PR that: 1) Updates a limited number of Python-exposed functions (no overloads) 2) Disables compactdefaultargs only for those functions 3) Adds a Python test using inspect.signature() to verify named parameters
I’ll scope the changes to Python-specific SWIG files to minimize any risk to Java/C# bindings and rely on CI to catch regressions there.
I’ll post the PR once the initial version is ready.