change plan to store individual relevant attrs

Storing individual contributing attributes will allow finer tuning of
the plan rendering.

add contributing to outputs

internal/command/views/plan.go

@@ -334,8 +334,8 @@ func renderChangesDetectedByRefresh(plan *plans.Plan, schemas *terraform.Schemas
 	// If this is not a refresh-only plan, we will need to filter out any
 	// non-relevant changes to reduce plan output.
 	relevant := make(map[string]bool)
-	for _, r := range plan.RelevantResources {
-		relevant[r.String()] = true
+	for _, r := range plan.RelevantAttributes {
+		relevant[r.Resource.String()] = true
 	}
 
 	// In refresh-only mode, we show all resources marked as drifted,

internal/plans/plan.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/hashicorp/terraform/internal/addrs"
 	"github.com/hashicorp/terraform/internal/configs/configschema"
+	"github.com/hashicorp/terraform/internal/lang/globalref"
 	"github.com/hashicorp/terraform/internal/states"
 	"github.com/zclconf/go-cty/cty"
 )
@@ -36,20 +37,15 @@ type Plan struct {
 	ForceReplaceAddrs []addrs.AbsResourceInstance
 	Backend           Backend
 
-	// RelevantResources is a set of resource addresses that are either
-	// directly affected by proposed changes or may have indirectly contributed
-	// to them via references in expressions.
+	// RelevantAttributes is a set of resource addresses and attributes that are
+	// either directly affected by proposed changes or may have indirectly
+	// contributed to them via references in expressions.
 	//
 	// This is the result of a heuristic and is intended only as a hint to
 	// the UI layer in case it wants to emphasize or de-emphasize certain
 	// resources. Don't use this to drive any non-cosmetic behavior, especially
 	// including anything that would be subject to compatibility constraints.
-	//
-	// FIXME: This result currently doesn't survive round-tripping through a
-	// saved plan file, and so it'll be populated only for a freshly-created
-	// plan that has only existed in memory so far. When reloading a saved
-	// plan it will always appear as if there are no "relevant resources".
-	RelevantResources []addrs.AbsResource
+	RelevantAttributes []globalref.ResourceAttr
 
 	// PrevRunState and PriorState both describe the situation that the plan
 	// was derived from:

internal/terraform/context_plan.go

@@ -200,10 +200,10 @@ The -target option is not for routine use, and is provided only for exceptional
 		panic("nil plan but no errors")
 	}
 
-	relevantResources, rDiags := c.relevantResourcesForPlan(config, plan)
+	relevantAttrs, rDiags := c.relevantResourceAttrsForPlan(config, plan)
 	diags = diags.Append(rDiags)
 
-	plan.RelevantResources = relevantResources
+	plan.RelevantAttributes = relevantAttrs
 	return plan, diags
 }
 
@@ -366,10 +366,10 @@ func (c *Context) destroyPlan(config *configs.Config, prevRunState *states.State
 		destroyPlan.PrevRunState = pendingPlan.PrevRunState
 	}
 
-	relevantResources, rDiags := c.relevantResourcesForPlan(config, destroyPlan)
+	relevantAttrs, rDiags := c.relevantResourceAttrsForPlan(config, destroyPlan)
 	diags = diags.Append(rDiags)
 
-	destroyPlan.RelevantResources = relevantResources
+	destroyPlan.RelevantAttributes = relevantAttrs
 	return destroyPlan, diags
 }
 
@@ -763,47 +763,38 @@ func (c *Context) referenceAnalyzer(config *configs.Config, state *states.State)
 
 // relevantResourcesForPlan implements the heuristic we use to populate the
 // RelevantResources field of returned plans.
-func (c *Context) relevantResourcesForPlan(config *configs.Config, plan *plans.Plan) ([]addrs.AbsResource, tfdiags.Diagnostics) {
+func (c *Context) relevantResourceAttrsForPlan(config *configs.Config, plan *plans.Plan) ([]globalref.ResourceAttr, tfdiags.Diagnostics) {
 	azr, diags := c.referenceAnalyzer(config, plan.PriorState)
 	if diags.HasErrors() {
 		return nil, diags
 	}
 
-	// Our current strategy is that a resource is relevant if it either has
-	// a proposed change action directly, or if its attributes are used as
-	// any part of a resource that has a proposed change action. We don't
-	// consider individual changed attributes for now, because we can't
-	// really reason about any rules that providers might have about changes
-	// to one attribute implying a change to another.
-
-	// We'll use the string representation of a resource address as a unique
-	// key so we can dedupe our results.
-	relevant := make(map[string]addrs.AbsResource)
-
 	var refs []globalref.Reference
 	for _, change := range plan.Changes.Resources {
 		if change.Action == plans.NoOp {
 			continue
 		}
-		instAddr := change.Addr
-		addr := instAddr.ContainingResource()
-		relevant[addr.String()] = addr
 
-		moreRefs := azr.ReferencesFromResourceInstance(instAddr)
+		moreRefs := azr.ReferencesFromResourceInstance(change.Addr)
 		refs = append(refs, moreRefs...)
 	}
 
-	contributors := azr.ContributingResources(refs...)
-	for _, addr := range contributors {
-		relevant[addr.String()] = addr
+	for _, change := range plan.Changes.Outputs {
+		if change.Action == plans.NoOp {
+			continue
+		}
+
+		moreRefs := azr.ReferencesFromOutputValue(change.Addr)
+		refs = append(refs, moreRefs...)
 	}
 
-	if len(relevant) == 0 {
-		return nil, diags
+	var contributors []globalref.ResourceAttr
+
+	for _, ref := range azr.ContributingResourceReferences(refs...) {
+		if res, ok := ref.ResourceAttr(); ok {
+			contributors = append(contributors, res)
+		}
 	}
-	ret := make([]addrs.AbsResource, 0, len(relevant))
-	for _, addr := range relevant {
-		ret = append(ret, addr)
-	}
-	return ret, diags
+
+	return contributors, diags
 }