This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.

If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.

This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.

If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.

This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.

If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.

This commit extracts the remaining UI logic from the local backend,
and removes access to the direct CLI output. This is replaced with an
instance of a `views.Operation` interface, which codifies the current
requirements for the local backend to interact with the user.

The exception to this at present is interactivity: approving a plan
still depends on the `UIIn` field for the backend. This is out of scope
for this commit and can be revisited separately, at which time the
`UIOut` field can also be removed.

Changes in support of this:

- Some instances of direct error output have been replaced with
  diagnostics, most notably in the emergency state backup handler. This
  requires reformatting the error messages to allow the diagnostic
  renderer to line-wrap them;
- The "in-automation" logic has moved out of the backend and into the
  view implementation;
- The plan, apply, refresh, and import commands instantiate a view and
  set it on the `backend.Operation` struct, as these are the only code
  paths which call the `local.Operation()` method that requires it;
- The show command requires the plan rendering code which is now in the
  views package, so there is a stub implementation of a `views.Show`
  interface there.

Other refactoring work in support of migrating these commands to the
common views code structure will come in follow-up PRs, at which point
we will be able to remove the UI instances from the unit tests for those
commands.

* providers.Interface: huge renamification

This commit renames a handful of functions in the providers.Interface to
match changes made in protocol v6. The following commit implements this
change across the rest of the codebase; I put this in a separate commit
for ease of reviewing and will squash these together when merging.

One noteworthy detail: protocol v6 removes the config from the
ValidateProviderConfigResponse, since it's never been used. I chose to
leave that in place in the interface until we deprecate support for
protocol v5 entirely.

Note that none of these changes impact current providers using protocol
v5; the protocol is unchanged. Only the translation layer between the
proto and terraform have changed.

Terraform supports multiple output formats for several sub-commands.
The default format is user-readable text, but many sub-commands support
a `-json` flag to output a machine-readable format for the result. The
output command also supports a `-raw` flag for a simpler, scripting-
focused machine readable format.

This commit adds a "views" abstraction, intended to help ensure
consistency between the various output formats. This extracts the render
specific code from the command package, and moves it into a views
package. Each command is expected to create an interface for its view,
and one or more implementations of that interface.

By doing so, we separate the concerns of generating the sub-command
result from rendering the result in the specified output format. This
should make it easier to ensure that all output formats will be updated
together when changes occur in the result-generating phase.

There are some other consequences of this restructuring:

- Views now directly access the terminal streams, rather than the
  now-redundant cli.Ui instance;
- With the reorganization of commands, parsing CLI arguments is now the
  responsibility of a separate "arguments" package.

For now, views are added only for the output sub-command, as an example.
Because this command uses code which is shared with the apply and
refresh commands, those are also partially updated.

Errors encountered when parsing flags for apply, plan, and refresh were
being suppressed. This resulted in a generic usage error when using an
invalid `-target` flag.

This commit makes several changes to address this. First, these commands
now output the flag parse error before exiting, leaving at least some
hint about the error. You can verify this manually with something like:

    terraform apply -invalid-flag

We also change how target attributes are parsed, moving the
responsibility from the flags instance to the command. This allows us to
customize the diagnostic output to be more user friendly. The
diagnostics now look like:

```shellsession
$ terraform apply -no-color -target=foo

Error: Invalid target "foo"

Resource specification must include a resource type and name.
```

Finally, we add test coverage for both parsing of target flags, and at
the command level for successful use of resource targeting. These tests
focus on the UI output (via the change summary and refresh logs), as the
functionality of targeting is covered by the context tests in the
terraform package.

The previous changes removing support for using the trailing positional
argument as a working directory missed a spot in the apply/destroy
command implementation. We still support this argument for applying a
saved plan:

    terraform apply foo.tfplan

However, if you pass a positional path which doesn't "look like" a plan
(for example, the path to a configuration directory), Terraform would
silently ignore it and continue.

This commit fixes that by adding an error message if the user specifies
a path which the plan loader rejects as not "looking like" a plan. This
message includes a reference to the `-chdir` flag as a pointer about
what to do next.

We also rearrange the error message when calling `terraform destroy`
with a plan file argument, and add test coverage for the above. While
we're here, update the destroy tests to copy the fixture directory,
chdir, and defer cleanup.

This dramatically simplifies the logic around auto-approve, which is
nice.

Also add test coverage for the manual approve step, for both apply and
destroy, answering both yes and no.

We can't get module instances during transformation, so we need to
reduce the Dependencies to using `addrs.ConfigResource` for now.

a large refactor to addrs.AbsProviderConfig, embedding the addrs.Provider instead of a Type string. I've added and updated tests, added some Legacy functions to support older state formats and shims, and added a normalization step when reading v4 (current) state files (not the added tests under states/statefile/roundtrip which work with both current and legacy-style AbsProviderConfig strings).

The remaining 'fixme' and 'todo' comments are mostly going to be addressed in a subsequent PR and involve looking up a given local provider config's FQN. This is fine for now as we are only working with default assumption.

* Introduce "Local" terminology for non-absolute provider config addresses

In a future change AbsProviderConfig and LocalProviderConfig are going to
become two entirely distinct types, rather than Abs embedding Local as
written here. This naming change is in preparation for that subsequent
work, which will also include introducing a new "ProviderConfig" type
that is an interface that AbsProviderConfig and LocalProviderConfig both
implement.

This is intended to be largely just a naming change to get started, so
we can deal with all of the messy renaming. However, this did also require
a slight change in modeling where the Resource.DefaultProviderConfig
method has become Resource.DefaultProvider returning a Provider address
directly, because this method doesn't have enough information to construct
a true and accurate LocalProviderConfig -- it would need to refer to the
configuration to know what this module is calling the provider it has
selected.

In order to leave a trail to follow for subsequent work, all of the
changes here are intended to ensure that remaining work will become
obvious via compile-time errors when all of the following changes happen:
- The concept of "legacy" provider addresses is removed from the addrs
  package, including removing addrs.NewLegacyProvider and
  addrs.Provider.LegacyString.
- addrs.AbsProviderConfig stops having addrs.LocalProviderConfig embedded
  in it and has an addrs.Provider and a string alias directly instead.
- The provider-schema-handling parts of Terraform core are updated to
  work with addrs.Provider to identify providers, rather than legacy
  strings.

In particular, there are still several codepaths here making legacy
provider address assumptions (in order to limit the scope of this change)
but I've made sure each one is doing something that relies on at least
one of the above changes not having been made yet.

* addrs: ProviderConfig interface

In a (very) few special situations in the main "terraform" package we need
to make runtime decisions about whether a provider config is absolute
or local.

We currently do that by exploiting the fact that AbsProviderConfig has
LocalProviderConfig nested inside of it and so in the local case we can
just ignore the wrapping AbsProviderConfig and use the embedded value.

In a future change we'll be moving away from that embedding and making
these two types distinct in order to represent that mapping between them
requires consulting a lookup table in the configuration, and so here we
introduce a new interface type ProviderConfig that can represent either
AbsProviderConfig or LocalProviderConfig decided dynamically at runtime.

This also includes the Config.ResolveAbsProviderAddr method that will
eventually be responsible for that local-to-absolute translation, so
that callers with access to the configuration can normalize to an
addrs.AbsProviderConfig given a non-nil addrs.ProviderConfig. That's
currently unused because existing callers are still relying on the
simplistic structural transform, but we'll switch them over in a later
commit.

* rename LocalType to LocalName
Co-authored-by: Kristin Laemmert <mildwonkey@users.noreply.github.com>

* huge change to weave new addrs.Provider into addrs.ProviderConfig
* terraform: do not include an empty string in the returned Providers /
Provisioners
- Fixed a minor bug where results included an extra empty string

Next to adding the locking for the `state push` command, this commit also fixes a small bug where the lock would not be propertly released when running the `state show` command.

And finally it renames some variables in the `[un]taint` code in order to try to standardize the var names of a few frequently used variables (e.g. statemgr.Full, states.State, states.SyncState).

Due to how often the state and plan types are referenced throughout
Terraform, there isn't a great way to switch them out gradually. As a
consequence, this huge commit gets us from the old world to a _compilable_
new world, but still has a large number of known test failures due to
key functionality being stubbed out.

The stubs here are for anything that interacts with providers, since we
now need to do the follow-up work to similarly replace the old
terraform.ResourceProvider interface with its replacement in the new
"providers" package. That work, along with work to fix the remaining
failing tests, will follow in subsequent commits.

The aim here was to replace all references to terraform.State and its
downstream types with states.State, terraform.Plan with plans.Plan,
state.State with statemgr.State, and switch to the new implementations of
the state and plan file formats. However, due to the number of times those
types are used, this also ended up affecting numerous other parts of core
such as terraform.Hook, the backend.Backend interface, and most of the CLI
commands.

Just as with 5861dbf3 before, I apologize
in advance to the person who inevitably just found this huge commit while
spelunking through the commit history.

The "config" package is no longer used and will be removed as part
of the 0.12 release cleanup. Since configschema is part of the
"new world" of configuration modelling, it makes more sense for
it to live as a subdirectory of the newer "configs" package.

This is not exhaustive, but it gets the tests in this package compiling
again and gets most of them working.

Since an early version of Terraform, the `destroy` command has always
had the `-force` flag to allow an auto approval of the interactive
prompt. 0.11 introduced `-auto-approve` as default to `false` when using
the `apply` command.

The `-auto-approve` flag was introduced to reduce ambiguity of it's
function, but the `-force` flag was never updated for a destroy.

People often use wrappers when automating commands in Terraform, and the
inconsistency between `apply` and `destroy` means that additional logic
must be added to the wrappers to do similar functions. Both commands are
more or less able to run with similar syntax, and also heavily share
their code.

This commit updates the command in `destroy` to use the `-auto-approve` flag
making working with the Terraform CLI a more consistent experience.

We leave in `-force` in `destroy` for the time-being and flag it as
deprecated to ensure a safe switchover period.

Previously we did plugin discovery in the main package, but as we move
towards versioned plugins we need more information available in order to
resolve plugins, so we move this responsibility into the command package
itself.

For the moment this is just preserving the existing behavior as long as
there are only internal and unversioned plugins present. This is the
final state for provisioners in 0.10, since we don't want to support
versioned provisioners yet. For providers this is just a checkpoint along
the way, since further work is required to apply version constraints from
configuration and support additional plugin search directories.

The automatic plugin discovery behavior is not desirable for tests because
we want to mock the plugins there, so we add a new backdoor for the tests
to use to skip the plugin discovery and just provide their own mock
implementations. Most of this diff is thus noisy rework of the tests to
use this new mechanism.

Gove LockInfo a Marshal method for easy serialization, and a String
method for more readable output.

Have the state.Locker implementations use LockError when possible to
return LockInfo and an error.

Make sure unlock is called with the correct LockID during operations

The new test pattern is to chdir into a temp location for the test, but
the prevents us from locating the testdata directory in the source. Add
a source path to testLockState so we can find the statelocker.go source.

This turns the new graphs on by default and puts the old graphs behind a
flag `-Xlegacy-graph`. This effectively inverts the current 0.7.x
behavior with the new graphs.

We've incubated most of these for a few weeks now. We've found issues
and we've fixed them and we've been using these graphs internally for
awhile without any major issue. Its time to default them on and get them
part of a beta.

Add `-target=resource` flag to core operations, allowing users to
target specific resources in their infrastructure. When `-target` is
used, the operation will only apply to that resource and its
dependencies.

The calculated dependencies are different depending on whether we're
running a normal operation or a `terraform destroy`.

Generally, "dependencies" refers to ancestors: resources falling
_before_ the target in the graph, because their changes are required to
accurately act on the target.

For destroys, "dependencies" are descendents: those resources which fall
_after_ the target. These resources depend on our target, which is going
to be destroyed, so they should also be destroyed.