Avoid backfilling property deps for Go

Two changes:

1. Change the Go SDK to always send a filled-in property dependencies map, which is consistent with all of the other language SDKs. This prevents the engine from backfilling an empty map with explicit dependencies specified in the `pulumi.DependsOn` `ResourceOption`.

2. Stop doing the backfilling in the engine when remote is true, because all clients that support remote already support passing property dependencies, so there's no need to backfill. The backfill behavior was meant for very old clients that didn't support sending property dependencies.

changelog/pending/20221014--sdk-go--avoid-backfilling-property-deps-go.yaml

@@ -0,0 +1,4 @@
+changes:
+- type: fix
+  scope: sdk/go
+  description: Avoid backfilling property deps for Go

pkg/resource/deploy/source_eval.go

@@ -1054,9 +1054,10 @@ func (rm *resmon) RegisterResource(ctx context.Context,
 	}
 
 	propertyDependencies := make(map[resource.PropertyKey][]resource.URN)
-	if len(req.GetPropertyDependencies()) == 0 {
+	if len(req.GetPropertyDependencies()) == 0 && !remote {
 		// If this request did not specify property dependencies, treat each property as depending on every resource
-		// in the request's dependency list.
+		// in the request's dependency list. We don't need to do this when remote is true, because all clients that
+		// support remote already support passing property dependencies, so there's no need to backfill here.
 		for pk := range props {
 			propertyDependencies[pk] = dependencies
 		}

sdk/go/pulumi/rpc.go

@@ -143,12 +143,9 @@ func marshalInputs(props Input) (resource.PropertyMap, map[string][]URN, []URN,
 		}
 		deps.union(allDeps)
 
-		if len(allDeps) > 0 {
-			pdeps[pname] = allDeps.values()
-		}
-
 		if !v.IsNull() || len(allDeps) > 0 {
 			pmap[resource.PropertyKey(pname)] = v
+			pdeps[pname] = allDeps.values()
 		}
 		return nil
 	}

sdk/go/pulumi/rpc_test.go

@@ -238,7 +238,7 @@ func TestMarshalRoundtrip(t *testing.T) {
 	if assert.Nil(t, err) {
 		assert.Equal(t, reflect.TypeOf(inputs).NumField(), len(resolved))
 		assert.Equal(t, 10, len(deps))
-		assert.Equal(t, 10, len(pdeps))
+		assert.Equal(t, 25, len(pdeps))
 
 		// Now just unmarshal and ensure the resulting map matches.
 		resV, secret, err := unmarshalPropertyValue(ctx, resource.NewObjectProperty(resolved))
@@ -586,7 +586,7 @@ func TestMarshalRoundtripNestedSecret(t *testing.T) {
 		const resourceFields = 10
 		assert.Equal(t, reflect.TypeOf(inputs).NumField()-resourceFields, len(resolved))
 		assert.Equal(t, 0, len(deps))
-		assert.Equal(t, 0, len(pdeps))
+		assert.Equal(t, 15, len(pdeps))
 
 		// Now just unmarshal and ensure the resulting map matches.
 		resV, secret, err := unmarshalPropertyValue(ctx, resource.NewObjectProperty(resolved))
@@ -1757,3 +1757,20 @@ func TestOutputValueMarshallingEnums(t *testing.T) {
 		})
 	}
 }
+
+func TestMarshalInputsPropertyDependencies(t *testing.T) {
+	t.Parallel()
+
+	pmap, pdeps, deps, err := marshalInputs(testInputs{
+		S: String("a string"),
+		A: Bool(true),
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, resource.PropertyMap{
+		"s": resource.NewStringProperty("a string"),
+		"a": resource.NewBoolProperty(true),
+	}, pmap)
+	assert.Equal(t, []URN{}, deps)
+	// Expect a non-empty property deps map, even when there aren't any deps.
+	assert.Equal(t, map[string][]URN{"s": {}, "a": {}}, pdeps)
+}