Fallback to system modules if vendorized one do not exist #1745
@rpkilby There was a ticket for this for Invoke at one point, the tl;dr is that some OS level packages don't agree with vendoring and prefer to distribute a copy of the code that expects a "regularly" installed copy of those deps.
So e.g. Debian might yank out
"Normal" installs from pip will always end up using the vendored copy, but with this change in play, the code can be used by those OS downstream packages as-is without them having to apply additional patches.
Note that this is subtly different from the inverse, preferring the public copy of a module and only falling back to the vendored one, which has its own issues and is not desirable.
Interesting, I didn't realize that this occurred. Thanks for the info.