This adds the Taint field to the acceptance testing framework, allowing
the ability to pre-taint resources at the beginning of a particular
TestStep. This can be useful for when an explicit ForceNew is required
for a specific resource for troubleshooting things like diff mismatches,
etc.
The field accepts resource addresses as a list of strings. To keep
things simple for the time being, only addresses in the root module are
accepted. If we ever want to expand this past that, I'd be almost
inclined to add some facilities to the core terraform package to help
translate actual module resource addresses (ie:
module.foo.module.bar.some_resource.baz) into the correct state, versus
the current convention in some acceptance testing facilities that take
the module address as a list of strings (ie: []string{"root", "foo",
"bar"}).
When computing the count value, make sure to include walkDestroy with
walkApply, as the former is only a special case of the latter.
When applying a saved plan, the computed count values are lost and we
can no longer query the state for those values. The apply walk was
already considered in the `resourceCountMax` function, but the destroy
walk was not. This worked when destroying in a single operation
("terraform destroy"), since the state would still be updated with the
latest counts from the plan.
A couple of bugs have been discovered in ResourceDiff.ForceNew:
* NewRemoved is not preserved when a diff for a key is already present.
This is because the second diff that happens after customization
performs a second getChange on not just state and config, but also on
the pre-existing diff. This results in Exists == true, meaning nil is
never returned as a new value.
* ForceNew was doing the work of adding the key to the list of changed
keys by doing a full SetNew on the existing value. This has a side
effect of fetching zero values from what were otherwise undefined values
and creating diffs for these values where there should not have been
(example: "" => "0").
This update fixes these scenarios by:
* Adding a new private function to check the existing diff for
NewRemoved keys. This is included in the check on new values in
diffChange.
* Keys that have been flagged as ForceNew (or parent keys of lists and
sets that have been flagged as ForceNew) are now maintained in a
separate map. UpdatedKeys now returns the results of both of these maps,
but otherwise these keys are ignored by ResourceDiff.
* Pursuant the above, values are no longer pushed into the newDiff
writer by ForceNew. This prevents the zero value problem, and makes for
a cleaner implementation where the provider has to "manually" SetNew to
update the appropriate values in the writer. It also prevents
non-computed keys from winding up in the diff, which ResourceDiff
normally blocks by design.
There are also a couple of tests for cases that should never come up
right now involving Optional/Computed values and NewRemoved, for which
explanations are given in annotations of each test. These are here to
guard against future regressions.
Chris