We expect that in order to continue to evolve the language without
breaking existing modules we will at some point need to have a way to mark
when a particular module is expecting a newer interpretation of the
language.
Although it's too early to do any deep preparation for that, this commit
aims to proactively reserve an argument named "language" inside
"terraform" blocks, which currently only accepts the keyword TF2021 that
is intended to represent "the edition of the Terraform language as defined
in 2021".
That argument also defaults to TF2021 if not set, so in practice there's
no real reason to set this today, but this minimal validation today is
intended to give better feedback to users of older Terraform versions in
the event that we introduce a new language edition later and they try to
use an module incompatible with their Terraform version.
Add support for parsing configuration_aliases in required_providers
entries. The decoder needed to be re-written here in order to support
the bare reference style usage of provider names so that they match the
usage in other location within configuration. The only change to
existing handling of the required_providers block is more precise error
locations in a couple cases.
Remove chef, habitat, puppet, and salt-masterless provsioners,
which follows their deprecation. Update the documentatin for these
provisioners to clarify that they have been removed from later versions
of Terraform. Adds the fmt Make target back and updates fmtcheck script
for correctness.
The main motivation here is to produce a helpful error if a user
incorrectly uses the terraform-provider- prefix (which we see on provider
VCS repositories and plugin executables) as part of the source address.
However, this also more broadly blocks "terraform-" as a prefix in
anticipation of whatever instinct causes the phenomenon where e.g.
Python's PyPI has thousands of packages whose names start with "python-",
even though everything on PyPI is for Python by definition. This is
definitely not _necessary_, but it's better to be restrictive at first
and weaken later as needed.
With provider dependencies now appearing inside a nested block, it seems
likely that configuration examples showing dependencies out of context
will sometimes mislead users into thinking that required_providers is
toplevel.
To give better feedback in that situation, we'll produce a specialized
error in that case hinting the correct structure to the user.
Martin Atkins