opentofu/internal/terraform/transform_variable.go
Martin Atkins 37b1413ab3 core: Handle root and child module input variables consistently
Previously we had a significant discrepancy between these two situations:
we wrote the raw root module variables directly into the EvalContext and
then applied type conversions only at expression evaluation time, while
for child modules we converted and validated the values while visiting
the variable graph node and wrote only the _final_ value into the
EvalContext.

This confusion seems to have been the root cause for #29899, where
validation rules for root module variables were being applied at the wrong
point in the process, prior to type conversion.

To fix that bug and also make similar mistakes less likely in the future,
I've made the root module variable handling more like the child module
variable handling in the following ways:
 - The "raw value" (exactly as given by the user) lives only in the graph
   node representing the variable, which mirrors how the _expression_
   for a child module variable lives in its graph node. This means that
   the flow for the two is the same except that there's no expression
   evaluation step for root module variables, because they arrive as
   constant values from the caller.
 - The set of variable values in the EvalContext is always only "final"
   values, after type conversion is complete. That in turn means we no
   longer need to do "just in time" conversion in
   evaluationStateData.GetInputVariable, and can just return the value
   exactly as stored, which is consistent with how we handle all other
   references between objects.

This diff is noisier than I'd like because of how much it takes to wire
a new argument (the raw variable values) through to the plan graph builder,
but those changes are pretty mechanical and the interesting logic lives
inside the plan graph builder itself, in NodeRootVariable, and
the shared helper functions in eval_variable.go.

While here I also took the opportunity to fix a historical API wart in
EvalContext, where SetModuleCallArguments was built to take a set of
variable values all at once but our current caller always calls with only
one at a time. That is now just SetModuleCallArgument singular, to match
with the new SetRootModuleArgument to deal with root module variables.
2022-01-10 12:26:54 -08:00

44 lines
1015 B
Go

package terraform
import (
"github.com/hashicorp/terraform/internal/addrs"
"github.com/hashicorp/terraform/internal/configs"
)
// RootVariableTransformer is a GraphTransformer that adds all the root
// variables to the graph.
//
// Root variables are currently no-ops but they must be added to the
// graph since downstream things that depend on them must be able to
// reach them.
type RootVariableTransformer struct {
Config *configs.Config
RawValues InputValues
}
func (t *RootVariableTransformer) Transform(g *Graph) error {
// We can have no variables if we have no config.
if t.Config == nil {
return nil
}
// We're only considering root module variables here, since child
// module variables are handled by ModuleVariableTransformer.
vars := t.Config.Module.Variables
// Add all variables here
for _, v := range vars {
node := &NodeRootVariable{
Addr: addrs.InputVariable{
Name: v.Name,
},
Config: v,
RawValue: t.RawValues[v.Name],
}
g.Add(node)
}
return nil
}