ScopedModuleNameOverride

[tdegeus]

I have a set of functions written in C++ that I compile in a module _foo.
My python module simply imports all functions from it. I.e. foo/__init__.py reads

from _foo import *

This was giving issues with my documentation. And I got the suggestion sphinx-doc/sphinx#10199 to use:

/**
Overrides the `__name__` of a module.
Classes defined by pybind11 use the `__name__` of the module as of the time they are defined,
which affects the `__repr__` of the class type objects.
*/
class ScopedModuleNameOverride {
public:
    explicit ScopedModuleNameOverride(py::module m, std::string name) : module_(std::move(m))
    {
        original_name_ = module_.attr("__name__");
        module_.attr("__name__") = name;
    }
    ~ScopedModuleNameOverride()
    {
        module_.attr("__name__") = original_name_;
    }

private:
    py::module module_;
    py::object original_name_;
};

PYBIND11_MODULE(_foo, mod)
{
    ScopedModuleNameOverride name_override(m, "foo");
}

See https://github.com/google/tensorstore/blob/94be4f2e8715511bb60fc0a0eaf07335881673b3/python/tensorstore/tensorstore.cc#L75

It would be great if this could be incorporated as option in pybind11 !

[rwgk]

At first sight I thought this looks interesting, but at second thought, in-place modifications like this usually come with pitfalls & surprises. (BTW: I'd definitely delete the copy & move constructor & operator in the tensorstore implementation; it'll be surprising and bug-prone if the object is accidentally copied or moved.)

I think it would be safer and more obvious to create a module_alias, a new object, which has all the attributes we need, exactly the same is m, except __name__.

auto ma = m.make_alias("foo");

or

auto ma = m.make_alias(py::module_::strip_leading_underscore_from_name);

Then use ma instead of m for the .defs etc. That will be completely obvious, and much less surprising to someone glancing through the code while debugging, for example (i.e. with the mind somewhere else, which is >90% how I usually read code).

[tdegeus]

make_alias seems like a great solution! And the helper too! I would open a PR if I would know how/where to implement this (which I sadly dont‘t)

[rwgk]

This is an OSS project. Try!

[tdegeus]

@rwgk Am I on the right track if I put:

    struct strip_leading_underscore_from_name;

    static module_ make_alias(const char *name) {
        module_ ret = *this;
        ret.attr("__name__") = this.attr(name);
        return ret;
    }

    static module_ make_alias(strip_leading_underscore_from_name) {
        auto name = ??
        return this->make_alias(name);
    }

as members of module_?

[tdegeus]

Here is my (potentially naive ;)) try : #3761