Are we content to say that sys.path includes the source directory where the hook is run? Shall I prepare a PR against the PEP for that?
On Sun, Jul 30, 2017, at 02:12 PM, Nick Coghlan wrote: > On 30 July 2017 at 02:46, Nathaniel Smith <n...@pobox.com> wrote: > > Or am I worrying about a non-issue and it's fine if flit imports click from > > the source tree? > > Don't worry about it too much, as the problem here isn't really any > worse than it is for normal runtime dependencies of any other project > that relies on having the current directory first in sys.path. It just > so happens that the project in question in this case is a Python > project's build system. > > Due to the preference for a flat module namespace as the default, > there are plenty of ways to hit name shadowing problems in Python, and > as Donald notes, build systems have other motives to vendor their > dependencies rather than installing them normally. > > Just switching the path order as has been suggested also doesn't solve > the problem, as it merely inverts the issue: having "some_name" > installed in site-packages would break source installations of > packages that expected to be able to import "some_name" from their own > root directory. > > If the problem does come up in practice, then there are a number of > ways for affected projects to work around it in their project > directory structure: > > 1. Use a top-level "src" directory (we may want to reserve "src" on PyPI) > 2. Use a top-level "tools" directory (we may want to reserve "tools" on > PyPI) > 3. Add a leading or trailing underscore to the local directory name > (as while that's legal for Python imports, it's prohibited for PyPI > project names, and hence will often sidestep naming conflicts with > published packages) > > Beyond that, the only approaches I'm aware of that systematically > avoid this kind of problem at the language design level are to either > use URL-based imports (ala Java or Go), or else to have separate > syntax for "system-only" and "local resolution permitted" imports (ala > C and C++), and Guido opted not to pursue either of those strategies > for Python. > > Cheers, > Nick. > > -- > Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org https://mail.python.org/mailman/listinfo/distutils-sig
