Because CBD now runs after a RootTransformer, it's now operating on a
graph that _may_ have had a graphNodeRoot added to it (a noop node whose
only purpose is to be a root).
CBD includes a step that tells the destroy node to depend on any parents
of the create node. When one of those parents was "root", this was
causing the destroy node to depend on "root", making it cease to be an
actual root node.
Because graphNodeRoot is a singleton, the follow-up RootTransformer was
not sufficient to slap another root on top - it wasn't being seen as a
fresh node, so edges were just accumulating, and we ended up in a state
with "no roots".
refs #1903 (not sure if this will fix all the "no root found" cases, or
just the one I bumped into)
fixes#1947
Root cause was a bad edge being made by the CBD transform going from the
flattened destroy node to the unflattened create node, which was no
longer in the graph. The destroy node therefore had a dependency that
could never be satisfied, which locked up the walk.
Got this while playing around in a module:
> * unflattenable node: aws_security_group.internal (orphan)
> *terraform.graphNodeOrphanResource
Basically just copied implementation from
d503cc2d82
Adds the ability to target resources within modules, like:
module.mymod.aws_instance.foo
And the ability to target all resources inside a module, like:
module.mymod
Closes#1434
This reimplements my prior attempt at nipping issues where a plan did
not yield the same cycle an apply did. My prior attempt was to have
ctx.Validate generate a "Verbose" worst-case graph. It turns out that
skipping PruneDestroyTransformer to generate this graph misses important
heuristics that prevent cycles by dropping destroy nodes that are
determined to be unused.
This resulted in Validate improperly failing in scenarios where these
heuristics would have broken the cycle.
We detected the problem during the work on #1781 and worked around the
issue by reverting to the non-Verbose graph in Validate.
This commit accomplishes the original goal in a better way - by
generating the full graph and checking it once Plan has calculated the
diff. This guarantees that any graph issue that would be caught by Apply
will be caught by Plan.
Clint Shryock