This changes the contract for `PlanResourceChange` so that the provider is now responsible
for populating all default values during plan, including inserting any unknown values for
defaults it will fill in at apply time.
Objects with DynamicPseudoType attributes can't be coerced within a map
if a concrete type is set. Change the Value type used to an Object when
there is a type mismatch.
We've changed the contract for PlanResourceChange to now require the
provider to populate any default values (including unknowns) it wants to
set for computed arguments, so our mock provider here now needs to be a
little more complex to deal with that.
This fixes several of the tests in this package. A minor change to
TestLocal_applyEmptyDirDestroy was required to make it properly configure
the mock provider so PlanResourceChange can access the schema.
We now require a provider to populate all of its defaults -- including
unknown value placeholders -- during PlanResourceChange. That means the
mock provider for testing "terraform show -json" must now manage the
population of the computed "id" attribute during plan.
To make this logic a little easier, we also change the ApplyResourceChange
implementation to fill in a non-null id, since that makes it easier for
the mock PlanResourceChange to recognize when it needs to populate that
default value during an update.
Check attributes on null objects, and fill in unknowns. If we're
evaluating the object, it either means we are at the top level, or a
NestingSingle block was present, and in either case we need to treat the
attributes as null rather than the entire object.
Switch on the block types rather than Nesting, so we don't need add any
logic to change between List/Tuple or Map/Object when DynamicPseudoType
is involved.
In an earlier commit we changed objchange.ProposedNewObject so that the
task of populating unknown values for attributes not known during apply
is the responsibility of the provider's PlanResourceChange method, rather
than being handled automatically.
However, we were also using objchange.ProposedNewObject to construct the
placeholder new object for a deferred data resource read, and so we
inadvertently broke that deferral behavior. Here we restore the old
behavior by introducing a new function objchange.PlannedDataResourceObject
which is a specialized version of objchange.ProposedNewObject that
includes the forced behavior of populating unknown values, because the
provider gets no opportunity to customize a deferred read.
TestContext2Plan_createBeforeDestroy_depends_datasource required some
updates here because its implementation of PlanResourceChange was not
handling the insertion of the unknown value for attribute "computed".
The other changes here are just in an attempt to make the flow of this
test more obvious, by clarifying that it is simulating a -refresh=false
run, which effectively forces a deferred read since we skip the eager
read that would normally happen in the refresh step.
Now that ProposedNewState uses null to represent Computed attributes not
set in the configuration, the provider must fill in the unknown value for
"computed" in its plan result.
It seems that this test was incorrectly updated during our bulk-fix after
integrating the HCL2 work, but it didn't really matter because the
ReadDataSource function isn't called in the happy path anyway. But to
make the intent clearer here, we also now make ReadDataSource return an
error if it is called, making it explicit that no call is expected.
Data resources do not have a plan/apply distinction, so it is never valid
for a data resource to produce unknown values in its result object.
Unknown values in the data resource _config_ cause us to postpone the read
altogether, so a data source never receives unknown values as input and
therefore may never produce unknown values as output.
Previously we would construct a proposed new state with unknown values in
place of any not-set-in-config computed attributes, trying to save the
provider a little work in specifying that itself.
Unfortunately that turns out to be problematic because it conflates two
concerns: attributes can be explicitly set in configuration to an unknown
value, in which case the final result of that unknown overrides any
default value the provider might normally populate.
In other words, this allows the provider to recognize in the proposed new
state the difference between an Optional+Computed attribute being set to
unknown in the config vs not being set in the config at all.
The provider now has the responsibility to replace these proposed null
values with unknown values during PlanResourceChange if it expects to
select a value during the apply step. It may also populate a known value
if the final result can be predicted at plan time, as is the case for
constant defaults specified in the provider code.
This change comes from a realization that from core's perspective the
helper/schema ideas of zero values, explicit default values, and
customizediff tweaks are all just examples of "defaults", and by allowing
the provider to see during plan whether these attributes are being
explicitly set in configuration and thus decide whether the default will
be provided immediately during plan or deferred until apply.
The shim layer for the legacy SDK type system is not precise enough to
guarantee it will produce identical results between plan and apply. In
particular, values that are null during plan will often become zero-valued
during apply.
To avoid breaking those existing providers while still allowing us to
introduce this check in the future, we'll introduce a rather-hacky new
flag that allows the legacy SDK to signal that it is the legacy SDK and
thus disable the check.
Once we start phasing out the legacy SDK in favor of one that natively
understands our new type system, we can stop setting this flag and thus
get the additional safety of this check without breaking any
previously-released providers.
No other SDK is permitted to set this flag, and we will remove it if we
ever introduce protocol version 6 in future, assuming that any provider
supporting that protocol will always produce consistent results.
Previously we would allow providers to change anything about the planned
object value during apply, possibly returning an entirely-unrelated object
of the same type. In practice this led to some subtle bugs where a single
planned attribute value would change during apply and cause a downstream
failure due to a dependent resource now seeing input other than what
_it_ expected during plan.
Now we'll produce an explicit error message for this case which places the
blame with the correct party: the upstream resource that changed. Without
this, unexpected changes would often lead to the downstream resource
implementation being blamed in error message even though it was just
reacting to the change from upstream.
As with most errors during apply, we'll still save the updated value in
the state but we'll halt the walk to ensure that the unexpected value
cannot propagate further and cause the result to potentially diverge
greatly from the changeset shown in the plan.
Compared to Terraform 0.11, we expect to see this error in many of the
same cases we saw the "diffs didn't match during apply" error in earlier
versions, since it is likely that many errors of that sort were the result
of unexpected upstream changes being incorrectly blamed on the downstream
resource that then used the result.
Because Terraform Core has traditionally not checked that the final apply
result is consistent with what was planned, some of our apply tests were
producing inconsistent results.
Here we fix all of that so that they produce something compatible with
what they planned. This doesn't actually achieve anything in isolation,
but we're about to start enforcing this consistency in a subsequent
commit.
It seems that all of the tools we run here are now sufficiently
modules-aware to run without problems in modules mode, and indeed running
_not_ in modules mode was causing problems with locating packages in
mockgen.
In 0.12, the outputs for a data source of terraform_remote_state are
nested under the 'outputs' attribute [1]. This updates the docs
to make this change clearer.
Worked with @radeksimko at Terraform hackday, who has submitted a
related upgrade guide [2]
[1] 1f4d2f4c50/builtin/providers/terraform/data_source_state.go (L16-L43)
[2] d8e00191b7
If set elements are computed, we can't be certain that they are actually
equal. Catch identical computed set hashes when they are added to the
set, and alter the set key slightly to keep the set counts correct.
In previous versions the interpolation string would be included in the
set, and different string values would cause the set to hash
differently, so this is change is only activated for the new protocol.
This turns it on at the last moment, and in one place for all uses of
helper/schema. There's no way to use the new protocol without calling
GetSchema, so we can be sure that any subsequent api calls have this set
when required.
Sets rely on diffs being complete for all elements, even when they are
unchanged. When encountering a DiffSuppressFunc inside a set the diffs
were being dropped entirely, possible causing set elements to be lost.
Previously we were just asserting that the number of elements didn't grow
between planned and actual. We still can't precisely correlate elements in
sets with unknown values, but here we adapt some logic we added earlier
to config/hcl2shim to ensure that we can find a plausible correlation for
each element in each set to at least one element in the other set, and
thus catch more cases where set elements might vanish or appear between
plan and apply, for improved safety.
This will still generate false negatives in some cases where unknown
values are present due to having to assume correlation is intended
wherever it is possible, but we'll catch situations where the actual value
is obviously contrary to what was planned.
Martin Atkins