maturin develop does not install dependencies

[cassiersg]

When adding a section

 [package.metadata.maturin]
requires-dist = ["flask~=1.1.0", "toml==0.10.0"]

in Cargo.toml, the dependencies are not installed in the current virtualenv when running maturin develop.
Is this the expected behavior ?

If so, it is a bit annoying: the simplest way I found for installing the python dependencies specified in Cargo.toml is to build the wheel and install it. Is there a better solution ? I believe this could be mentioned in the README.

Please provide the following information:

• Your python version (python -V): 3.7.3
• Your pip version (pip -V): 21.0.1
  • If this isn't the latest pip version, have you checked using the latest pip version? This is the latest pip version
• The version of the bindings you're using, if any (e.g. pyo3, rust-cpython or cffi): pyo3=0.13
• Does cargo build work? yes
• If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)? N/A (on linux)

[konstin]

Currently, this is missing from develop. If anyone want to implement this, this should be the right location:

maturin/src/develop.rs

Lines 44 to 49 in 7c43487

	let interpreter = PythonInterpreter::check_executable(python, &target, &build_context.bridge)?
	.ok_or_else(|| {
	anyhow!("Expected `python` to be a python interpreter inside a virtualenv ಠ_ಠ")
	})?;
	let mut builder = PathWriter::venv(&target, &venv_dir, &build_context.bridge)?;

Check whether build_context.metadata21.requires_dist has any entries and if so, call python -m pip on all of them (at once, invoking pip is slow). For the test, pick a dependency-less, pure-python package from pypi as test requirement, extend an existing test with that package as requirement and check that the requirement is installed in check_installed.py.