This fixes an issue where orphaned grandchild modules don't properly
inherit their provider configurations from grandparents. I found this
while working on shadow graphs (the shadow graph actually caught an
inconsistency between runs and exposed this bug!), so I'm unsure if this
affects any issue.
To better explain the issue, I'll diagram things.
Here is a hierarchy that _works_ (w/o this PR):
```
root
|-- child1 (orphan)
|-- child2
|-- grandchild
```
All modules in this case will successfully inherit provider
configurations from "root".
Here is a hierarchy that _doesn't work without this PR_:
```
root
|-- child1 (orphan)
|-- grandchild (orphan)
```
In this case, `child1` does successfully inherit the provider from root,
but `grandchild` _will not_ unless `child1` had resources. If `child1`
has no resources, it wouldn't inherit anything. This PR fixes that.
The flattening process was not properly drawing dependencies between provider
nodes in modules and their parent provider nodes.
Fixes#2832Fixes#4443Fixes#4865
The `CloseProviderTransformer` relies on the `ProvidedBy()` interface to
look up the proper dependency for the the graph nodes it adds. This
interface needs to yield the name of a provider, _AND_ for flattened
nodes it needs to yield the full path to a provider.
Destroy nodes did not implement this second part, which resulted in
"provider X couldn't be found" when both of these were true:
* A module included a resource that dependend on a provider
* The root did _NOT_ include a provider config
Implementing a proper ProvidedBy() on the flattened version of
destroy nodes solves the issue.
fixes#2581
When targeting prunes out all the resource nodes between a provider and
its close node, there was no dependency to ensure the close happened
after the configure. Needed to add an explicit dependency from the close
to the provider.
This tweak highlighted the fact that CloseProviderTransformer needed to
happen after DisableProviderTransformer, since
DisableProviderTransformer inspects up-edges to decide what to disable,
and CloseProviderTransformer adds an up-edge.
fixes#2495
Currently Terraform is leaking goroutines and with that memory. I know
strictly speaking this maybe isn’t a real concern for Terraform as it’s
mostly used as a short running command line executable.
But there are a few of us out there that are using Terraform in some
long running processes and then this starts to become a problem.
Next to that it’s of course good programming practise to clean up
resources when they're not needed anymore. So even for the standard
command line use case, this seems an improvement in resource management.
Personally I see no downsides as the primary connection to the plugin
is kept alive (the plugin is not killed) and only unused connections
that will never be used again are closed to free up any related
goroutines and memory.
When you specify `-verbose` you'll get the whole graph of operations,
which gives a better idea of the operations terraform performs and in
what order.
The DOT graph is now generated with a small internal library instead of
simple string building. This allows us to ensure the graph generation is
as consistent as possible, among other benefits.
We set `newrank = true` in the graph, which I've found does just as good
a job organizing things visually as manually attempting to rank the nodes
based on depth.
This also fixes `-module-depth`, which was broken post-AST refector.
Modules are now expanded into subgraphs with labels and borders. We
have yet to regain the plan graphing functionality, so I removed that
from the docs for now.
Finally, if `-draw-cycles` is added, extra colored edges will be drawn
to indicate the path of any cycles detected in the graph.
A notable implementation change included here is that
{Reverse,}DepthFirstWalk has been made deterministic. (Before it was
dependent on `map` ordering.) This turned out to be unnecessary to gain
determinism in the final DOT-level implementation, but it seemed
a desirable enough of a property that I left it in.
The provider config was not being properly merged across module
boundaries during the Input walk over the graph, so when a provider was
configured at the top level, resources in modules could improperly
trigger a request for input for a provider attribute that's already
defined.
