v1.16.5/internal/terraform/transform_output.go

// Copyright IBM Corp. 2014, 2026
// SPDX-License-Identifier: BUSL-1.1

package terraform

import (
	"log"

	"github.com/hashicorp/terraform/internal/addrs"
	"github.com/hashicorp/terraform/internal/configs"
	"github.com/hashicorp/terraform/internal/moduletest/mocking"
)

// OutputTransformer is a GraphTransformer that adds all the outputs
// in the configuration to the graph.
//
// This is done for the apply graph builder even if dependent nodes
// aren't changing since there is no downside: the state will be available
// even if the dependent items aren't changing.
type OutputTransformer struct {
	Config *configs.Config

	// Refresh-only mode means that any failing output preconditions are
	// reported as warnings rather than errors
	RefreshOnly bool

	// Planning must be set to true only when we're building a planning graph.
	// It must be set to false whenever we're building an apply graph.
	Planning bool

	// If this is a planned destroy, root outputs are still in the configuration
	// so we need to record that we wish to remove them.
	Destroying bool

	// AllowRootEphemeralOutputs overrides a specific check made within the
	// output nodes that they cannot be ephemeral at within root modules. This
	// should be set to true for plans executing from within either the stacks
	// or test runtimes, where the root modules as Terraform sees them aren't
	// the actual root modules.
	AllowRootEphemeralOutputs bool

	// Overrides supplies the values for any output variables that should be
	// overridden by the testing framework.
	Overrides *mocking.Overrides
}

func (t *OutputTransformer) Transform(g *Graph) error {
	return t.transform(g, t.Config)
}

func (t *OutputTransformer) transform(g *Graph, c *configs.Config) error {
	// If we have no config then there can be no outputs.
	if c == nil {
		return nil
	}

	// Transform all the children. We must do this first because
	// we can reference module outputs and they must show up in the
	// reference map.
	for _, cc := range c.Children {
		if err := t.transform(g, cc); err != nil {
			return err
		}
	}

	for _, o := range c.Module.Outputs {
		addr := addrs.OutputValue{Name: o.Name}

		node := &nodeExpandOutput{
			Addr:                      addr,
			Module:                    c.Path,
			Config:                    o,
			Destroying:                t.Destroying,
			RefreshOnly:               t.RefreshOnly,
			Planning:                  t.Planning,
			Overrides:                 t.Overrides,
			AllowRootEphemeralOutputs: t.AllowRootEphemeralOutputs,
		}

		log.Printf("[TRACE] OutputTransformer: adding %s as %T", o.Name, node)
		g.Add(node)
	}

	return nil
}