Qiskit / qiskit / 37006716374

88%

main: 88%

Build Type

push

github

Committed by web-flow

Commit Message

Add base implementation of `LoweringPassManager` (#17105)

* Add base implementation of `LoweringPassManager`

The `PyIrExposer`/`CIrExposer` system is clearly missing the ability to
attach it to the dynamic-typing system (this isn't new to this commit),
but that seems like a hard problem that we don't have time to solve
right now.

Nevertheless, this system now fulfils the base Python API we were
attempting to implement, within quite a few limitations.

* Fix potential deadlock in malformed Python `__del__`

Running the `Drop` impl on `Py<PyAny>` can run arbitrary Python code if
the refcount drops to 0 and CPython calls the object's `__del__` method.
We should ensure we've dropped the rw-lock before allowing that, to
avoid a (pathological, but possible) deadlock if the `__del__` attempts
to do something with the context handle.

* Use `anyhow` exception chaining now Python global state

This was always going to be a little fragile; if control ever passed to
the Python interpreter between the pass raising the exception and us
taking it again, it would have caused problems.  Fortunately, `anyhow`
has chain tooling that we can re-use.

* Set `pyclass` modules

Coverage Stats

19 of 87 new or added lines in 3 files covered. (21.84%)

6 existing lines in 2 files now uncovered.

122886 of 139733 relevant lines covered (87.94%)

937834.05 hits per line