Add a new ChangeReason, ReasonDeleteBecauseNoMoveTarget, to provide better
information in cases where a planned deletion is due to moving a resource to
a target not in configuration.
Consider a case in which a resource instance exists in state at address A, and
the user adds a moved block to move A to address B. Whether by the user's
intention or not, address B does not exist in configuration.
Terraform combines the move from A to B, and the lack of configuration for B,
into a single delete action for the (previously nonexistent) entity B.
Prior to this commit, the Terraform plan will report that resource B will be
destroyed because it does not exist in configuration, without explicitly
connecting this to the move.
This commit provides the user an additional clue as to what has happened, in a
case in which Terraform has elided a user's action and inaction into one
potentially destructive change.
By observing the sorts of questions people ask in the community, and the
ways they ask them, we've inferred that various different people have been
confused by Terraform reporting that a value won't be known until apply
or that a value is sensitive as part of an error message when that message
doesn't actually relate to the known-ness and sensitivity of any value.
Quite reasonably, someone who sees Terraform discussing an unfamiliar
concept like unknown values can assume that it must be somehow relevant to
the problem being discussed, and so in that sense Terraform's current
error messages are giving "too much information": information that isn't
actually helpful in understanding the problem being described, and in the
worst case is a distraction from understanding the problem being described.
With that in mind then, here we introduce an explicit annotation on
diagnostic objects that are directly talking about unknown values or
sensitive values, and then the diagnostic renderer will react to that to
avoid using the terminology "known only after apply" or "sensitive" in the
generated diagnostic annotations unless we're rendering a message that is
explicitly related to one of those topics.
This ends up being a bit of a cross-cutting concern because the code that
generates these diagnostics and the code that renders them are in separate
packages and are not directly aware of each other. With that in mind, the
logic for actually deciding for a particular diagnostic whether it's
flagged in one of these special ways lives inside the tfdiags package as
an intermediation point, which both the diagnostic generator (in the core
package) and the diagnostic renderer can both depend on.
When an error occurs in a function call, the error message text often
includes references to particular parameters in the function signature.
This commit improves that reporting by also including a summary of the
full function signature as part of the diagnostic context in that case,
so a reader can see which parameter is which given that function
arguments are always assigned positionally and so the parameter names
do not appear in the caller's source code.
We have two different reasons why a data resource might be read only
during apply, rather than during planning as usual: the configuration
contains unknown values, or the data resource as a whole depends on a
managed resource which itself has a change pending.
However, we didn't previously distinguish these two in a way that allowed
the UI to describe the difference, and so we confusingly reported both
as "config refers to values not yet known", which in turn led to a number
of reasonable questions about why Terraform was claiming that but then
immediately below showing the configuration entirely known.
Now we'll use our existing "ActionReason" mechanism to tell the UI layer
which of the two reasons applies to a particular data resource instance.
The "dependency pending" situation tends to happen in conjunction with
"config unknown", so we'll prefer to refer that the configuration is
unknown if both are true.
The extra feedback information for why resource instance deletion is
planned is now included in the streaming JSON UI output.
We also add an explicit case for no-op actions to switch statements in
this package to ensure exhaustiveness, for future linting.
Add previous address information to the `planned_change` and
`resource_drift` messages for the streaming JSON UI output of plan and
apply operations.
Here we also add a "move" action value to the `change` object of these
messages, to represent a move-only operation.
As part of this work we also simplify this code to use the plan's
DriftedResources values instead of recomputing the drift from state.
Extend the outputs JSON log message to support an `action` field (and
make the `type` and `value` fields optional). This allows us to emit a
useful output change summary as part of the plan, bringing the JSON log
output into parity with the text output.
While we do have access to the before/after values in the output
changes, attempting to wedge those into a structured log message is not
appropriate. That level of detail can be extracted from the JSON plan
output from `terraform show -json`.
Because our snippet generator is trying to select whole lines to include
in the snippet, it has some edge cases for odd situations where the
relevant source range starts or ends directly at a newline, which were
previously causing this logic to return out-of-bounds offsets into the
code snippet string.
Although arguably it'd be better for the original diagnostics to report
more reasonable source ranges, it's better for us to report a
slightly-inaccurate snippet than to crash altogether, and so we'll extend
our existing range checks to check both bounds of the string and thus
avoid downstreams having to deal with out-of-bounds indices.
For completeness here I also added some similar logic to the
human-oriented diagnostic formatter, which consumes the result of the
JSON diagnostic builder. That's not really needed with the additional
checks in the JSON diagnostic builder, but it's nice to reinforce that
this code can't panic (in this way, at least) even if its input isn't
valid.
This was dead code, and there is no clear way to retrieve this
information, as we currently only derive the drift information as part
of the rendering process.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
