The issue is about exceptions bubbling up to the interface level, not about crashing pip. For example, if some class raises notimplemented error and pip interprets that to mean it should call build_wheel. On Aug 25, 2017 1:23 PM, "Paul Moore" <p.f.moore@gmail.com> wrote:
On 25 August 2017 at 18:06, xoviat <xoviat@gmail.com> wrote:
Is pip going to fall back to building a wheel directly if any other error is raised? That's what happens with setup.py install. If so, then it may be fine if unexpected exceptions bubble up.
Given that hooks need to be called in a subprocess (see https://www.python.org/dev/peps/pep-0517/#id15, "Frontends should call each hook in a fresh subprocess, so that backends are free to change process global state") there's no "bubbling up" involved at all. The frontend code would be something along the lines of
hook_stub = ''' import backend try: backend.build_sdist(...) except NotImplementedError: sys.exit(1) sys.exit(0) ''' # Or... hook_stub = ''' import backend if backend.build_sdist(...) == NotImplemented: sys.exit(1) sys.exit(0) '''
if subprocess.call([sys.executable, "-c", hook_stub]) != 0: # We didn't build a sdist
There's little or no opportunity here for letting exceptions bubble up to the user, or passing complex data back to the frontend. Ultimately, it's pretty much immaterial which form of reporting is used.
Paul