Merge pull request #26284 from hashicorp/jbardin/data-resource-reference

delay data source reads with pending resource ref

terraform/context_plan_test.go

@@ -6370,3 +6370,41 @@ data "test_data_source" "d" {
 		t.Fatal("expected data.test_data_source.d to be fully read in refreshed state, got status", d.Current.Status)
 	}
 }
+
+func TestContext2Plan_dataReferencesResource(t *testing.T) {
+	p := testProvider("test")
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+
+	p.ReadDataSourceFn = func(req providers.ReadDataSourceRequest) (resp providers.ReadDataSourceResponse) {
+		resp.Diagnostics = resp.Diagnostics.Append(fmt.Errorf("data source should not be read"))
+		return resp
+	}
+
+	m := testModuleInline(t, map[string]string{
+		"main.tf": `
+locals {
+	x = "value"
+}
+
+resource "test_resource" "a" {
+	value = local.x
+}
+
+// test_resource.a.value can be resolved during plan, but the reference implies
+// that the data source should wait until the resource is created.
+data "test_data_source" "d" {
+	foo = test_resource.a.value
+}
+`})
+
+	ctx := testContext2(t, &ContextOpts{
+		Config: m,
+		Providers: map[addrs.Provider]providers.Factory{
+			addrs.NewDefaultProvider("test"): testProviderFuncFixed(p),
+		},
+	})
+
+	_, diags := ctx.Plan()
+	assertNoErrors(t, diags)
+}

terraform/transform_reference.go

@@ -46,6 +46,7 @@ type GraphNodeAttachDependencies interface {
 // graphNodeDependsOn is implemented by resources that need to expose any
 // references set via DependsOn in their configuration.
 type graphNodeDependsOn interface {
+	GraphNodeReferencer
 	DependsOn() []*addrs.Reference
 }
 
@@ -327,6 +328,31 @@ func (m ReferenceMap) dependsOn(g *Graph, depender graphNodeDependsOn) ([]dag.Ve
 
 	refs := depender.DependsOn()
 
+	// For data sources we implicitly treat references as depends_on entries.
+	// If a data source references a resource, even if that reference is
+	// resolvable, it stands to reason that the user intends for the data
+	// source to require that resource in some way.
+	if n, ok := depender.(GraphNodeConfigResource); ok &&
+		n.ResourceAddr().Resource.Mode == addrs.DataResourceMode {
+		for _, r := range depender.References() {
+
+			// We don't need to wait on referenced data sources. They have no
+			// side effects, so our configuration reference should suffice for
+			// proper ordering.
+			var resAddr addrs.Resource
+			switch s := r.Subject.(type) {
+			case addrs.Resource:
+				resAddr = s
+			case addrs.ResourceInstance:
+				resAddr = s.Resource
+			}
+
+			if resAddr.Mode == addrs.ManagedResourceMode {
+				refs = append(refs, r)
+			}
+		}
+	}
+
 	// This is where we record that a module has depends_on configured.
 	if _, ok := depender.(*nodeExpandModule); ok && len(refs) > 0 {
 		fromModule = true