If an instance object in state has an earlier schema version number then
it is likely that the schema we're holding won't be able to decode the
raw data that is stored. Instead, we must ask the provider to upgrade it
for us first, which might also include translating it from flatmap form
if it was last updated with a Terraform version earlier than v0.12.
This ends up being a "seam" between our use of int64 for schema versions
in the providers package and uint64 everywhere else. We intend to
standardize on int64 everywhere eventually, but for now this remains
consistent with existing usage in each layer to keep the type conversion
noise contained here and avoid mass-updates to other Terraform components
at this time.
This also includes a minor change to the test helpers for the
backend/local package, which were inexplicably setting a SchemaVersion of
1 on the basic test state but setting the mock schema version to zero,
creating an invalid situation where the state would need to be downgraded.
The rest of Terraform is still using uint64 for this in various spots, but
we'll update that gradually later. We use int64 here because that matches
what's used in our protobuf definition, and unsigned integers are not
portable across all of the protobuf target languages anyway.
There's no reason for a negative version, so by blocking it now we'll
ensure that none creep in.
The more practical short-term motivation for this is that we're still
using uint64 for these internally in some cases and so this restriction
ensures that we won't run into rough edges when converting from int64 to
uint64 at those boundaries until we later fix everything to use int64
consistently.
Add support for the new `force-unlock` API and at the same time improve
performance a bit by reducing the amount of API calls made when using
the remote backend for state storage only.
Previously we were making an invalid assumption in evaluating module call
references (like module.foo) that the module must exist, which is
incorrect for that particular case because it's a reference to a child
module, not to an object within the current module.
However, now that we have the mechanism for static validation of
references, we'll deal with this one there so it can be caught sooner.
That then makes the original assumption valid, though for a different
reason.
This is verified by two new context tests for validation:
- TestContext2Validate_invalidModuleRef
- TestContext2Validate_invalidModuleOutputRef
Now that our language supports tuple/object types in addition to list/map
types, it's convenient for zipmap to be able to produce an object type
given a tuple, since this makes it symmetrical with "keys" and "values"
such the the following identity holds for any map or object value "a"
a == zipmap(keys(a), values(a))
When the values sequence is a tuple, the result has an object type whose
attribute types correspond to the given tuple types.
Since an object type has attribute names as part of its definition, there
is the additional constraint here that the result has an unknown type
(represented by the dynamic pseudo-type) if the given values is a tuple
and the given keys contains any unknown values. This isn't true for values
as a list because we can predict the resulting map element type using
just the list element type.
Previously we were fetching these from the provider but then immediately
discarding the version numbers because the schema API had nowhere to put
them.
To avoid a late-breaking change to the internal structure of
terraform.ProviderSchema (which is constructed directly all over the
tests) we're retaining the resource type schemas in a new map alongside
the existing one with the same keys, rather than just switching to
using the providers.Schema struct directly there.
The methods that return resource type schemas now return two arguments,
intentionally creating a little API friction here so each new caller can
be reminded to think about whether they need to do something with the
schema version, though it can be ignored by many callers.
Since this was a breaking change to the Schemas API anyway, this also
fixes another API wart where there was a separate method for fetching
managed vs. data resource types and thus every caller ended up having a
switch statement on "mode". Now we just accept mode as an argument and
do the switch statement within the single SchemaForResourceType method.
When normalizing flatmapped containers, compare the attributes to the
prior state and preserve pre-existing zero-length or unknown values. A
zero-length value that was previously unknown is preserved as a
zero-length value, as that may have been computed as such by the
provider.
Since the SDK's schema system conflates attributes and nested blocks, it's
possible to state some nonsensical schema situations such as:
- A nested block is both optional but has MinItems > 0
- A nested block is entirely computed but has MinItems or MaxItems set
Both of these weird situations are handled here in the same way that the
existing helper/schema validation code would've handled them: by
effectively disabling the MinItems/MaxItems checks where they would've
been ignored before.
the MinItems/MaxItems
The SDK has a mechanism that effectively makes it possible to declare an
attribute as being _conditionally_ required, which is not a concept that
Terraform Core is aware of.
Since this mechanism is in practice only used for a small UX improvement
in prompting for these values interactively when the environment variable
is not set, we avoid here introducing all of this complexity into the
plugin protocol by just having the provider selectively modify its schema
if it detects that such an attribute might be set dynamically.
This then prevents Terraform Core from validating the presence of the
argument or prompting for a new value for it, allowing the null value to
pass through into the provider so that the default value can be generated
again dynamically.
This is a kinda-kludgey solution which we're accepting here because the
alternative would be a much-more-complex two-pass decode operation within
Core itself, and that doesn't seem worth it.
This fixes#19139.
In the initial move to HCL2 we started relying only on full expression
evaluation to catch attribute errors, but that's not sufficient for
resource attributes in practice because during validation we can't know
yet whether a resource reference evaluates to a single object or to a
list of objects (if count is set).
To address this, here we reinstate some static validation of resource
references by analyzing directly the reference objects, disregarding any
instance index if present, and produce errors if the remaining subsequent
traversal steps do not correspond to items within the resource type
schema.
This also allows us to produce some more specialized error messages for
certain situations. In particular, we can recognize a reference like
aws_instance.foo.count, which in 0.11 and prior was a weird special case
for determining the count value of a resource block, and offer a helpful
error showing the new length(aws_instance.foo) usage pattern.
This eventually delegates to the static traversal validation logic that
was added to the configschema package in a previous commit, which also
includes some specialized error messages that distinguish between
attributes and block types in the schema so that the errors relate more
directly to constructs the user can see in the configuration.
In future we could potentially move more of the checks from the dynamic
schema construction step to the static validation step, but resources
are the reference type that most needs this immediately due to the
ambiguity caused by the instance indexing syntax. We can safely refactor
other reference types to be statically validated in later releases.
This is verified by two pre-existing context validate tests which we
temporarily disabled during earlier work (now re-enabled) and also by a
new validate test aimed specifically at the special case for the "count"
attribute.
This allows basic static validation of a traversal against a schema, to
verify that it represents a valid path through the structural parts of
the schema.
The main purpose of this is to produce better error messages (using our
knowledge of the schema) than we'd be able to achieve by just relying
on HCL expression evaluation errors. This is particularly important for
nested blocks because it may not be obvious whether one is represented
internally by a set or a list, and incorrect usage would otherwise produce
a confusing HCL-oriented error message.
Martin Atkins