The SearchLocalDirectory function was intentionally written to only
support symlinks at the leaves so that it wouldn't risk getting into an
infinite loop traversing intermediate symlinks, but that rule was also
applying to the base directory itself.
It's pretty reasonable to put your local plugins in some location
Terraform wouldn't normally search (e.g. because you want to get them from
a shared filesystem mounted somewhere) and creating a symlink from one
of the locations Terraform _does_ search is a convenient way to help
Terraform find those without going all in on the explicit provider
installation methods configuration that is intended for more complicated
situations.
To allow for that, here we make a special exception for the base
directory, resolving that first before we do any directory walking.
In order to help with debugging a situation where there are for some
reason symlinks at intermediate levels inside the search tree, we also now
emit a WARN log line in that case to be explicit that symlinks are not
supported there and to hint to put the symlink at the top-level if you
want to use symlinks at all.
(The support for symlinks at the deepest level of search is not mentioned
in this message because we allow it primarily for our own cache linking
behavior.)
* internal/getproviders: fix panic with invalid path parts
If the search path is missing a directory, the provider installer would
try to create an addrs.Provider with the wrong parts. For example if the
hostname was missing (as in the test case), it would call
addrs.NewProvider with (namespace, typename, version). This adds a
validation step for each part before calling addrs.NewProvider to avoid
the panic.
This is a basic implementation of FilesystemMirrorSource for now aimed
only at the specific use-case of scanning the cache of provider plugins
Terraform will keep under the ".terraform" directory, as part of our
interim provider installer implementation for Terraform 0.13.
The full functionality of this will grow out in later work when we
implement explicit local filesystem mirrors, but for now the goal is to
use this just to inspect the work done by the automatic installer once
we switch it to the new provider-FQN-aware directory structure.
The various FIXME comments in this are justified by the limited intended
scope of this initial implementation, and they should be resolved by
later work to use FilesystemMirrorSource explicitly for user-specified
provider package mirrors.
Martin Atkins