We previously attempted to make the special diff apply behavior for nested
sets of objects work with attribute mode by totally discarding attribute
mode for all shims.
In practice, that is too broad a solution: there are lots of other shimming
behaviors that we _don't_ want when attribute mode is enabled. In
particular, we need to make sure that the difference between null and
empty can be seen in configuration.
As a compromise then, we will give all of the shims access to the real
ConfigMode and then do a more specialized fixup within the diff-apply
logic: we'll construct a synthetic nested block schema and then use that
to run our existing logic to deal with nested sets of objects, while
using the previous behavior in all other cases.
In effect, this means that the special new behavior only applies when the
provider uses the opt-in ConfigMode setting on a particular attribute,
and thus this change has much less risk of causing broad, unintended
regressions elsewhere.
Due to the lossiness of our legacy models for diff and state, shimming a
diff and then creating a state from it produces a different result than
shimming a state directly. That means that ImportStateVerify no longer
works as expected if there are any Computed attributes in the schema where
d.Set isn't called during Read.
Fixing that for every case would require some risky changes to the shim
behavior, so we're instead going to ask provider developers to address it
by adding `d.Set` calls where needed, since that is the contract for
"Computed" anyway -- a default value should be produced during Create, and
thus by extension during Import.
However, since a common situation where this occurs is attributes marked
as "Removed", since all of the code that deals with them has generally
been deleted, we'll avoid problems in that case here by treating Removed
attributes as ignored for the purposes of ImportStateVerify.
This required exporting some functionality that was formerly unexported
in helper/schema, but it's a relatively harmless schema introspection
function so shouldn't be a big deal to export it.
In study of existing providers we've found a pattern we werent previously
accounting for of using a nested block type to represent a group of
arguments that relate to a particular feature that is always enabled but
where it improves configuration readability to group all of its settings
together in a nested block.
The existing NestingSingle was not a good fit for this because it is
designed under the assumption that the presence or absence of the block
has some significance in enabling or disabling the relevant feature, and
so for these always-active cases we'd generate a misleading plan where
the settings for the feature appear totally absent, rather than showing
the default values that will be selected.
NestingGroup is, therefore, a slight variation of NestingSingle where
presence vs. absence of the block is not distinguishable (it's never null)
and instead its contents are treated as unset when the block is absent.
This then in turn causes any default values associated with the nested
arguments to be honored and displayed in the plan whenever the block is
not explicitly configured.
The current SDK cannot activate this mode, but that's okay because its
"legacy type system" opt-out flag allows it to force a block to be
processed in this way anyway. We're adding this now so that we can
introduce the feature in a future SDK without causing a breaking change
to the protocol, since the set of possible block nesting modes is not
extensible.
The synthetic config value used to create the Apply diff should contain
no unknown config values. Any remaining UnknownConfigValues were due to
that being used as a placeholder for values yet to be computed, and
these should be marked NewComputed in the diff.
Stripping these was a patch for some provider behavior which was fixed
in other ways, and is no longer needed.
Removing this allows us to implement correct CusomizeDiffFuncs in
providers so that they can mark fields with empty values as computed
during a plan.
A list-like attribute containing null values will present a list to
helper/schema with nils, which can cause panics. Since null values were
not possible in configuration before HCL2 and not supported by the
legacy SDK, return an error to the user.
It turns out that collections containing only unknowns could be lost,
meaning there wasn't a direct correlation between the unknown and null
value which would have otherwise been restored.
The legacy diff process inserts unknown values into an optional+computed
map. Fix these up in post-plan normalization process, by looking for
known strings that were changed to unknown.
Because schema.ResourceDiff can't differentiate between unknown
values and new computed values, unknowns can be lost during an update.
If a planned value converted an unknown to a null, restore the unknown
so that it can be correctly replaced in the final plan.
Add the (forces new resource) annotation to the diff output for provider
tests failures when we can. This helps providers narrow down what might
be triggering changes when encountering test failures with the new SDK.
The previous commit added this flag but did not implement it. Here we
implement it by adjusting the shape of schema we return to Terraform Core
to mark the attribute as untyped and then ensure that gets handled
correctly on the SDK side.
When running in v0.12-and-higher mode, this will cause the SDK to report
the type of the attribute as "any", effectively skipping type checking
on the Core side altogether and checking only in the SDK and provider
code.
The practical impact of this is to restore the v0.11-style checking
behavior of allowing object values to be missing certain attributes as
long as they are marked as optional in the schema. The SDK can do this
because it uses a unified schema model for both object values and nested
blocks, while Terraform Core only supports the idea of "optional" when
talking about attributes in nested blocks.
This is a continuation of the pile of workarounds that also includes
the ConfigMode and AsSingle fields, allowing providers to selectively opt
out of new v0.12 behaviors in situations where they conflict with
decisions made in the design of the providers in our old world where
Terraform Core delegated _all_ validation to providers.
This is designed as an opt-in so that we can limit its impact only to
specific cases where it's needed and minimize the risk of regressions
elsewhere. Providers should use this sparingly only in situations where
prevailing usage disagrees with the new expectations of Terraform Core in
v0.12.
This commit only adds the flag, and does not implement any behavior for it
yet. That means this commit can exist in both the v0.11 and v0.12
codebases, allowing for API compatibility. A subsequent commit for v0.12
(not included in v0.11) will then implement this behavior.
It's important to preserve the provider address because during the destroy
phase of provider tests we'll use the references in the state to determine
which providers are required, and so without this attempts to override
the provider using the "provider" meta-argument can cause failures at
destroy time when the wrong provider gets selected.
(This is particularly acute in the google-beta provider tests because that
provider is _always_ used with provider = "google-beta" to override the
default behavior of using the normal "google" provider.)
The previous commit added a new flag to schema.Schema which is documented
to make a list with MaxItems: 1 be presented to Terraform Core as a single
value instead, giving a way to switch to non-list nested resources without
it being a breaking change for Terraform v0.11 users as long as it's done
prior to a provider's first v0.12-compatible release.
This is the implementation of that mechanism. It's intentionally
implemented as a suite of extra fixups rather than direct modifications to
existing shim code because we want to ensure that this has no effect
whatsoever on the result of a resource type that _isn't_ using AsSingle.
Although there is some small unit test coverage of the fixup steps here,
the primary testing for this is in the test provider since the integration
of all of these fixup steps in the correct order is the more important
result than any of the intermediate fixup steps.
This setting indicates that an attribute defined as TypeList or TypeSet
should be presented to Terraform Core as a single value instead when
running in Terraform v0.12 or later. It has no effect for Terraform v0.10
or v0.11.
This commit just introduces the setting without any associated behavior,
so it can be included in both the v0.12 and v0.11 branches. A subsequent
commit only to the v0.12 branch will introduce the behavior as part of
the protocol version 5 shims.
This will allow resources to return an unexpected change to set blocks
and attributes, otherwise we could mask these changes during
normalization.
Change the "plan" argument in normalizeNullValues to "preferDst" to more
accurately describe what the option is doing, since it no longer applies
only to PlanResourceChange.
This should be the final change from removing the flatmap normalization.
Since we're no longer trying to a consistent zero or null value in the
flatmap config, rather we're trying to maintain the previously applied
value, ReadResource also needs to apply the normalizeNullValues step in
order to prevent unexpected diffs.
This method was added early on when the diff was being applied as the
legacy code would have done, which is no longer the case. Everything
that normalizeFlatmapContainers does should be covered by the
combination of the initial diff.Apply and the normalizeNullValues on the
final cty.Value.
This makes some slight adjustments to the shape of the schema we
present to Terraform Core without affecting how it is consumed by the
SDK and thus the provider. This mechanism is designed specifically to
avoid changing how the schema is interpreted by the SDK itself or by the
provider, so that prior behavior can be preserved in Terraform v0.11 mode.
This also includes a new rule that Computed-only (i.e. not also Optional)
schemas _always_ map to attributes, because that is a better mapping of
the intent: they are object values to be used in expressions. Nested
blocks conceptually represent nested objects that are in some sense
independent of what they are embedded in, and so they cannot themselves be
computed.
This allows a provider developer slightly more control over how an SDK
schema is mapped into the Terraform configuration language, overriding
some default assumptions.
ConfigMode overrides the default assumption that a schema with
an Elem of type *Resource is to be mapped to configuration as a nested
block, allowing mapping as an attribute containing an object type instead.
These behaviors only apply when a provider is being used with Terraform
v0.12 or later. They are ignored altogether in Terraform v0.11 mode, to
preserve compatibility. We are adding these primarily to allow the v0.12
version of a resource type schema to be specified to match the prevailing
usage of it in existing configurations, in situations where the default
mapping to v0.12 concepts is not appropriate.
This commit adds only the fields themselves and the InternalValidate rules
for them. A subsequent commit for Terraform v0.12 will add the behavior
as part of the protocol version 5 shim layer.
As we've improved the cty.Value normalization, we need to remove
normalization procedures from the flatmap handling. Keeping the empty
containers in the flatmap will prevent unexpected nils from being added
to some schema configurations
Use objchange.NormalizeObjectFromLegacySDK to ensure that all objects
returned from the provider match what is expected based on the
configuration according to the schemas.
Providers were not strict (and were not forced to be) about customizing
the diff when a computed attribute needed to be updated during apply.
The fix we have in place to prevent loss of information during the
helper/schema apply process would add in single missing value back in.
The first place this was caught was when we attempt to fix up the
flatmapped attributes. The 1->0 count error is now better handled by our
cty.Value normalization step, so we can remove the special apply case
here altogether
The next place is in normalizeNullValues, and since the intent was to
re-insert missing zero-value lists and sets, adding a check for a length
of 0 protects us from adding in extra elements.
The new test fixture emulated common provider behavior of re-computing
values without customizing the diff. Since we can work around it, and
core will provider appropriate warnings, the shims should try to
maintain the legacy behavior.
The NewExtra values are stored outside the diff from plan, and the
original keys may not contain the ~ prefix. Adding the NewExtra back
into the diff with the mismatched key was causing an entire new set
element to be populated. Since this symbol isn't used to apply the diff
in helper/schema, we can simply strip them out.
The hcl2shims will always add in the timeouts block, because there's no
way to differentiate a null single block from an empty one in the
flatmapped state. Since we are only concerned with keeping the prior
timeouts value, always set the new value to null, and then copy over the
prior value if it exists.
When the user aborts input, it may end up as an unknown value, which
needs to be converted to null for PrepareConfig.
Allow PrepareConfig to accept null config values in order to fill in
missing defaults.
The new normalization should make preventing those changes unnecessary,
and will also prevent extra empty elements from being added when
resources are refreshed.
Alex Somesan