make GraphNodeExecutable return diagnostics

terraform/eval_variable.go

@@ -18,14 +18,12 @@ import (
 // This must be used only after any side-effects that make the value of the
 // variable available for use in expression evaluation, such as
 // EvalModuleCallArgument for variables in descendent modules.
-func evalVariableValidations(addr addrs.AbsInputVariableInstance, config *configs.Variable, expr hcl.Expression, ctx EvalContext) error {
+func evalVariableValidations(addr addrs.AbsInputVariableInstance, config *configs.Variable, expr hcl.Expression, ctx EvalContext) (diags tfdiags.Diagnostics) {
 	if config == nil || len(config.Validations) == 0 {
 		log.Printf("[TRACE] evalVariableValidations: not active for %s, so skipping", addr)
 		return nil
 	}
 
-	var diags tfdiags.Diagnostics
-
 	// Variable nodes evaluate in the parent module to where they were declared
 	// because the value expression (n.Expr, if set) comes from the calling
 	// "module" block in the parent module.
@@ -105,5 +103,5 @@ func evalVariableValidations(addr addrs.AbsInputVariableInstance, config *config
 		}
 	}
 
-	return diags.ErrWithWarnings()
+	return diags
 }

terraform/execute.go

@@ -1,9 +1,11 @@
 package terraform
 
+import "github.com/hashicorp/terraform/tfdiags"
+
 // GraphNodeExecutable is the interface that graph nodes must implement to
 // enable execution. This is an alternative to GraphNodeEvalable, which is in
 // the process of being removed. A given graph node should _not_ implement both
 // GraphNodeExecutable and GraphNodeEvalable.
 type GraphNodeExecutable interface {
-	Execute(EvalContext, walkOperation) error
+	Execute(EvalContext, walkOperation) tfdiags.Diagnostics
 }

terraform/graph_walk_context.go

@@ -125,29 +125,20 @@ func (w *ContextGraphWalker) Execute(ctx EvalContext, n GraphNodeExecutable) tfd
 	// Acquire a lock on the semaphore
 	w.Context.parallelSem.Acquire()
 
-	err := n.Execute(ctx, w.Operation)
+	diags := n.Execute(ctx, w.Operation)
 
 	// Release the semaphore
 	w.Context.parallelSem.Release()
 
-	if err == nil {
+	if !diags.HasErrors() {
-		return nil
+		return diags
 	}
 
 	// Acquire the lock because anything is going to require a lock.
 	w.errorLock.Lock()
 	defer w.errorLock.Unlock()
 
-	// If the error is non-fatal then we'll accumulate its diagnostics in our
+	err := diags.Err()
-	// non-fatal list, rather than returning it directly, so that the graph
-	// walk can continue.
-	if nferr, ok := err.(tfdiags.NonFatalError); ok {
-		w.NonFatalDiagnostics = w.NonFatalDiagnostics.Append(nferr.Diagnostics)
-		return nil
-	}
-
-	var diags tfdiags.Diagnostics
-
 	// Handle a simple early exit error
 	if errors.Is(err, EvalEarlyExitError{}) {
 		return nil
@@ -174,6 +165,5 @@ func (w *ContextGraphWalker) Execute(ctx EvalContext, n GraphNodeExecutable) tfd
 	// unpack this as one or more diagnostic messages and return that. If we
 	// get down here then the returned diagnostics will contain at least one
 	// error, causing the graph walk to halt.
-	diags = diags.Append(err)
 	return diags
 }

terraform/node_count_boundary.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // NodeCountBoundary fixes up any transitions between "each modes" in objects
@@ -14,12 +15,14 @@ type NodeCountBoundary struct {
 	Config *configs.Config
 }
 
+var _ GraphNodeExecutable = (*NodeCountBoundary)(nil)
+
 func (n *NodeCountBoundary) Name() string {
 	return "meta.count-boundary (EachMode fixup)"
 }
 
 // GraphNodeExecutable
-func (n *NodeCountBoundary) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeCountBoundary) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	// We'll temporarily lock the state to grab the modules, then work on each
 	// one separately while taking a lock again for each separate resource.
 	// This means that if another caller concurrently adds a module here while
@@ -42,10 +45,11 @@ func (n *NodeCountBoundary) Execute(ctx EvalContext, op walkOperation) error {
 			continue
 		}
 		if err := n.fixModule(ctx, addr); err != nil {
-			return err
+			diags = diags.Append(err)
+			return diags
 		}
 	}
-	return nil
+	return diags
 }
 
 func (n *NodeCountBoundary) fixModule(ctx EvalContext, moduleAddr addrs.ModuleInstance) error {

terraform/node_count_boundary_test.go

@@ -53,9 +53,9 @@ func TestNodeCountBoundaryExecute(t *testing.T) {
 	}
 	node := NodeCountBoundary{Config: config}
 
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("unexpected error: %s", err.Error())
+		t.Fatalf("unexpected error: %s", diags.Err())
 	}
 	if !state.HasResources() {
 		t.Fatal("resources missing from state")

terraform/node_data_destroy.go

@@ -1,6 +1,10 @@
 package terraform
 
-import "log"
+import (
+	"log"
+
+	"github.com/hashicorp/terraform/tfdiags"
+)
 
 // NodeDestroyableDataResourceInstance represents a resource that is "destroyable":
 // it is ready to be destroyed.
@@ -13,7 +17,7 @@ var (
 )
 
 // GraphNodeExecutable
-func (n *NodeDestroyableDataResourceInstance) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeDestroyableDataResourceInstance) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	log.Printf("[TRACE] NodeDestroyableDataResourceInstance: removing state object for %s", n.Addr)
 	ctx.State().SetResourceInstanceCurrent(n.Addr, nil, n.ResolvedProvider)
 	return nil

terraform/node_data_destroy_test.go

@@ -36,9 +36,9 @@ func TestNodeDataDestroyExecute(t *testing.T) {
 		}.Instance(addrs.NoKey).Absolute(addrs.RootModuleInstance),
 	}}
 
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("unexpected error: %s", err.Error())
+		t.Fatalf("unexpected error: %v", diags.Err())
 	}
 
 	// verify resource removed from state

terraform/node_local.go

@@ -128,10 +128,7 @@ func (n *NodeLocal) References() []*addrs.Reference {
 // NodeLocal.Execute is an Execute implementation that evaluates the
 // expression for a local value and writes it into a transient part of
 // the state.
-func (n *NodeLocal) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeLocal) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-
-	var diags tfdiags.Diagnostics
-
 	expr := n.Config.Expr
 	addr := n.Addr.LocalValue
 
@@ -150,23 +147,24 @@ func (n *NodeLocal) Execute(ctx EvalContext, op walkOperation) error {
 		}
 	}
 	if diags.HasErrors() {
-		return diags.Err()
+		return diags
 	}
 
 	val, moreDiags := ctx.EvaluateExpr(expr, cty.DynamicPseudoType, nil)
 	diags = diags.Append(moreDiags)
 	if moreDiags.HasErrors() {
-		return diags.Err()
+		return diags
 	}
 
 	state := ctx.State()
 	if state == nil {
-		return fmt.Errorf("cannot write local value to nil state")
+		diags = diags.Append(fmt.Errorf("cannot write local value to nil state"))
+		return diags
 	}
 
 	state.SetLocalValue(addr.Absolute(ctx.Path()), val)
 
-	return nil
+	return diags
 }
 
 // dag.GraphNodeDotter impl.

terraform/node_module_expand.go

@@ -99,7 +99,7 @@ func (n *nodeExpandModule) ReferenceOutside() (selfPath, referencePath addrs.Mod
 }
 
 // GraphNodeExecutable
-func (n *nodeExpandModule) Execute(ctx EvalContext, op walkOperation) error {
+func (n *nodeExpandModule) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	expander := ctx.InstanceExpander()
 	_, call := n.Addr.Call()
 
@@ -110,16 +110,18 @@ func (n *nodeExpandModule) Execute(ctx EvalContext, op walkOperation) error {
 		ctx = ctx.WithPath(module)
 		switch {
 		case n.ModuleCall.Count != nil:
-			count, diags := evaluateCountExpression(n.ModuleCall.Count, ctx)
+			count, ctDiags := evaluateCountExpression(n.ModuleCall.Count, ctx)
+			diags = diags.Append(ctDiags)
 			if diags.HasErrors() {
-				return diags.Err()
+				return diags
 			}
 			expander.SetModuleCount(module, call, count)
 
 		case n.ModuleCall.ForEach != nil:
-			forEach, diags := evaluateForEachExpression(n.ModuleCall.ForEach, ctx)
+			forEach, feDiags := evaluateForEachExpression(n.ModuleCall.ForEach, ctx)
+			diags = diags.Append(feDiags)
 			if diags.HasErrors() {
-				return diags.Err()
+				return diags
 			}
 			expander.SetModuleForEach(module, call, forEach)
 
@@ -128,7 +130,7 @@ func (n *nodeExpandModule) Execute(ctx EvalContext, op walkOperation) error {
 		}
 	}
 
-	return nil
+	return diags
 
 }
 
@@ -146,6 +148,7 @@ type nodeCloseModule struct {
 var (
 	_ GraphNodeReferenceable    = (*nodeCloseModule)(nil)
 	_ GraphNodeReferenceOutside = (*nodeCloseModule)(nil)
+	_ GraphNodeExecutable       = (*nodeCloseModule)(nil)
 )
 
 func (n *nodeCloseModule) ModulePath() addrs.Module {
@@ -170,7 +173,7 @@ func (n *nodeCloseModule) Name() string {
 	return n.Addr.String() + " (close)"
 }
 
-func (n *nodeCloseModule) Execute(ctx EvalContext, op walkOperation) error {
+func (n *nodeCloseModule) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	switch op {
 	case walkApply, walkDestroy:
 		state := ctx.State().Lock()
@@ -206,10 +209,11 @@ type nodeValidateModule struct {
 	nodeExpandModule
 }
 
+var _ GraphNodeExecutable = (*nodeValidateModule)(nil)
+
 // GraphNodeEvalable
-func (n *nodeValidateModule) Execute(ctx EvalContext, op walkOperation) error {
+func (n *nodeValidateModule) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	_, call := n.Addr.Call()
-	var diags tfdiags.Diagnostics
 	expander := ctx.InstanceExpander()
 
 	// Modules all evaluate to single instances during validation, only to
@@ -238,9 +242,5 @@ func (n *nodeValidateModule) Execute(ctx EvalContext, op walkOperation) error {
 		expander.SetModuleSingle(module, call)
 	}
 
-	if diags.HasErrors() {
+	return diags
-		return diags.ErrWithWarnings()
-	}
-
-	return nil
 }

terraform/node_module_expand_test.go

@@ -42,9 +42,9 @@ func TestNodeCloseModuleExecute(t *testing.T) {
 			StateState: state.SyncWrapper(),
 		}
 		node := nodeCloseModule{addrs.Module{"child"}}
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 
 		// Since module.child has no resources, it should be removed
@@ -62,9 +62,9 @@ func TestNodeCloseModuleExecute(t *testing.T) {
 		}
 		node := nodeCloseModule{addrs.Module{"child"}}
 
-		err := node.Execute(ctx, walkImport)
+		diags := node.Execute(ctx, walkImport)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 		if _, ok := state.Modules["module.child"]; !ok {
 			t.Fatal("module.child was removed from state, expected no-op")
@@ -87,9 +87,9 @@ func TestNodeValidateModuleExecute(t *testing.T) {
 			},
 		}
 
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %v", diags.Err())
 		}
 	})
 

terraform/node_module_variable.go

@@ -10,6 +10,7 @@ import (
 	"github.com/hashicorp/terraform/dag"
 	"github.com/hashicorp/terraform/instances"
 	"github.com/hashicorp/terraform/lang"
+	"github.com/hashicorp/terraform/tfdiags"
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/convert"
 )
@@ -141,7 +142,7 @@ func (n *nodeModuleVariable) ModulePath() addrs.Module {
 }
 
 // GraphNodeExecutable
-func (n *nodeModuleVariable) Execute(ctx EvalContext, op walkOperation) error {
+func (n *nodeModuleVariable) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	// If we have no value, do nothing
 	if n.Expr == nil {
 		return nil
@@ -155,13 +156,15 @@ func (n *nodeModuleVariable) Execute(ctx EvalContext, op walkOperation) error {
 	switch op {
 	case walkValidate:
 		vals, err = n.EvalModuleCallArgument(ctx, true)
-		if err != nil {
+		diags = diags.Append(err)
-			return err
+		if diags.HasErrors() {
+			return diags
 		}
 	default:
 		vals, err = n.EvalModuleCallArgument(ctx, false)
-		if err != nil {
+		diags = diags.Append(err)
-			return err
+		if diags.HasErrors() {
+			return diags
 		}
 	}
 

terraform/node_output.go

@@ -246,11 +246,10 @@ func (n *NodeApplyableOutput) References() []*addrs.Reference {
 }
 
 // GraphNodeExecutable
-func (n *NodeApplyableOutput) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeApplyableOutput) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	state := ctx.State()
 	if state == nil {
-		return nil
+		return
 	}
 
 	changes := ctx.Changes() // may be nil, if we're not working on a changeset
@@ -297,9 +296,24 @@ func (n *NodeApplyableOutput) Execute(ctx EvalContext, op walkOperation) error {
 			// marked as unknown. If the evaluator was able to find a type
 			// for the value in spite of the error then we'll use it.
 			n.setValue(state, changes, cty.UnknownVal(val.Type()))
-			return EvalEarlyExitError{}
+
+			// Keep existing warnings, while converting errors to warnings.
+			// This is not meant to be the normal path, so there no need to
+			// make the errors pretty.
+			var warnings tfdiags.Diagnostics
+			for _, d := range diags {
+				switch d.Severity() {
+				case tfdiags.Warning:
+					warnings = warnings.Append(d)
+				case tfdiags.Error:
+					desc := d.Description()
+					warnings = warnings.Append(tfdiags.SimpleWarning(fmt.Sprintf("%s:%s", desc.Summary, desc.Detail)))
+				}
+			}
+
+			return warnings
 		}
-		return diags.Err()
+		return diags
 	}
 	n.setValue(state, changes, val)
 
@@ -309,7 +323,7 @@ func (n *NodeApplyableOutput) Execute(ctx EvalContext, op walkOperation) error {
 		n.setValue(state, changes, val)
 	}
 
-	return nil
+	return diags
 }
 
 // dag.GraphNodeDotter impl.
@@ -350,7 +364,7 @@ func (n *NodeDestroyableOutput) temporaryValue() bool {
 }
 
 // GraphNodeExecutable
-func (n *NodeDestroyableOutput) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeDestroyableOutput) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	state := ctx.State()
 	if state == nil {
 		return nil

terraform/node_output_test.go

@@ -81,11 +81,11 @@ func TestNodeApplyableOutputExecute_invalidDependsOn(t *testing.T) {
 	})
 	ctx.EvaluateExprResult = val
 
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err == nil {
+	if !diags.HasErrors() {
 		t.Fatal("expected execute error, but there was none")
 	}
-	if got, want := err.Error(), "Invalid depends_on reference"; !strings.Contains(got, want) {
+	if got, want := diags.Err().Error(), "Invalid depends_on reference"; !strings.Contains(got, want) {
 		t.Errorf("expected error to include %q, but was: %s", want, got)
 	}
 }
@@ -102,11 +102,11 @@ func TestNodeApplyableOutputExecute_sensitiveValueNotOutput(t *testing.T) {
 	})
 	ctx.EvaluateExprResult = val
 
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err == nil {
+	if !diags.HasErrors() {
 		t.Fatal("expected execute error, but there was none")
 	}
-	if got, want := err.Error(), "Output refers to sensitive values"; !strings.Contains(got, want) {
+	if got, want := diags.Err().Error(), "Output refers to sensitive values"; !strings.Contains(got, want) {
 		t.Errorf("expected error to include %q, but was: %s", want, got)
 	}
 }
@@ -151,9 +151,9 @@ func TestNodeDestroyableOutputExecute(t *testing.T) {
 	}
 	node := NodeDestroyableOutput{Addr: outputAddr}
 
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("Unexpected error: %s", err.Error())
+		t.Fatalf("Unexpected error: %s", diags.Err())
 	}
 	if state.OutputValue(outputAddr) != nil {
 		t.Fatal("Unexpected outputs in state after removal")

terraform/node_provider.go

@@ -20,36 +20,37 @@ var (
 )
 
 // GraphNodeExecutable
-func (n *NodeApplyableProvider) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeApplyableProvider) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	_, err := ctx.InitProvider(n.Addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 	provider, _, err := GetProvider(ctx, n.Addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	switch op {
 	case walkValidate:
-		return n.ValidateProvider(ctx, provider)
+		return diags.Append(n.ValidateProvider(ctx, provider))
 	case walkPlan, walkApply, walkDestroy:
-		return n.ConfigureProvider(ctx, provider, false)
+		return diags.Append(n.ConfigureProvider(ctx, provider, false))
 	case walkImport:
-		return n.ConfigureProvider(ctx, provider, true)
+		return diags.Append(n.ConfigureProvider(ctx, provider, true))
 	}
-	return nil
+	return diags
 }
 
-func (n *NodeApplyableProvider) ValidateProvider(ctx EvalContext, provider providers.Interface) error {
+func (n *NodeApplyableProvider) ValidateProvider(ctx EvalContext, provider providers.Interface) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 
 	configBody := buildProviderConfig(ctx, n.Addr, n.ProviderConfig())
 
 	resp := provider.GetSchema()
 	diags = diags.Append(resp.Diagnostics)
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	configSchema := resp.Provider.Block
@@ -63,7 +64,7 @@ func (n *NodeApplyableProvider) ValidateProvider(ctx EvalContext, provider provi
 	configVal, configBody, evalDiags := ctx.EvaluateBlock(configBody, configSchema, nil, EvalDataForNoInstanceKey)
 	diags = diags.Append(evalDiags)
 	if evalDiags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	req := providers.PrepareProviderConfigRequest{
@@ -73,14 +74,13 @@ func (n *NodeApplyableProvider) ValidateProvider(ctx EvalContext, provider provi
 	validateResp := provider.PrepareProviderConfig(req)
 	diags = diags.Append(validateResp.Diagnostics)
 
-	return diags.ErrWithWarnings()
+	return diags
 }
 
 // ConfigureProvider configures a provider that is already initialized and retrieved.
 // If verifyConfigIsKnown is true, ConfigureProvider will return an error if the
 // provider configVal is not wholly known and is meant only for use during import.
-func (n *NodeApplyableProvider) ConfigureProvider(ctx EvalContext, provider providers.Interface, verifyConfigIsKnown bool) error {
+func (n *NodeApplyableProvider) ConfigureProvider(ctx EvalContext, provider providers.Interface, verifyConfigIsKnown bool) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	config := n.ProviderConfig()
 
 	configBody := buildProviderConfig(ctx, n.Addr, config)
@@ -88,14 +88,14 @@ func (n *NodeApplyableProvider) ConfigureProvider(ctx EvalContext, provider prov
 	resp := provider.GetSchema()
 	diags = diags.Append(resp.Diagnostics)
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	configSchema := resp.Provider.Block
 	configVal, configBody, evalDiags := ctx.EvaluateBlock(configBody, configSchema, nil, EvalDataForNoInstanceKey)
 	diags = diags.Append(evalDiags)
 	if evalDiags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	if verifyConfigIsKnown && !configVal.IsWhollyKnown() {
@@ -105,11 +105,11 @@ func (n *NodeApplyableProvider) ConfigureProvider(ctx EvalContext, provider prov
 			Detail:   fmt.Sprintf("The configuration for %s depends on values that cannot be determined until apply.", n.Addr),
 			Subject:  &config.DeclRange,
 		})
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	configDiags := ctx.ConfigureProvider(n.Addr, configVal)
 	configDiags = configDiags.InConfigBody(configBody)
 
-	return configDiags.ErrWithWarnings()
+	return configDiags
 }

terraform/node_provider_eval.go

@@ -1,5 +1,7 @@
 package terraform
 
+import "github.com/hashicorp/terraform/tfdiags"
+
 // NodeEvalableProvider represents a provider during an "eval" walk.
 // This special provider node type just initializes a provider and
 // fetches its schema, without configuring it or otherwise interacting
@@ -8,8 +10,10 @@ type NodeEvalableProvider struct {
 	*NodeAbstractProvider
 }
 
+var _ GraphNodeExecutable = (*NodeEvalableProvider)(nil)
+
 // GraphNodeExecutable
-func (n *NodeEvalableProvider) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeEvalableProvider) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	_, err := ctx.InitProvider(n.Addr)
-	return err
+	return diags.Append(err)
 }

terraform/node_provider_test.go

@@ -65,13 +65,13 @@ func TestNodeApplyableProviderExecute_unknownImport(t *testing.T) {
 	ctx := &MockEvalContext{ProviderProvider: provider}
 	ctx.installSimpleEval()
 
-	err := n.Execute(ctx, walkImport)
+	diags := n.Execute(ctx, walkImport)
-	if err == nil {
+	if !diags.HasErrors() {
 		t.Fatal("expected error, got success")
 	}
 
 	detail := `Invalid provider configuration: The configuration for provider["registry.terraform.io/hashicorp/foo"] depends on values that cannot be determined until apply.`
-	if got, want := err.Error(), detail; got != want {
+	if got, want := diags.Err().Error(), detail; got != want {
 		t.Errorf("wrong diagnostic detail\n got: %q\nwant: %q", got, want)
 	}
 

terraform/node_provisioner.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/hashicorp/terraform/addrs"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // NodeProvisioner represents a provider that has no associated operations.
@@ -39,6 +40,6 @@ func (n *NodeProvisioner) ProvisionerName() string {
 }
 
 // GraphNodeExecutable impl.
-func (n *NodeProvisioner) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeProvisioner) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	return ctx.InitProvisioner(n.NameValue)
+	return diags.Append(ctx.InitProvisioner(n.NameValue))
 }

terraform/node_resource_abstract.go

@@ -305,8 +305,7 @@ func (n *NodeAbstractResource) DotNode(name string, opts *dag.DotOpts) *dag.DotN
 // eval is the only change we get to set the resource "each mode" to list
 // in that case, allowing expression evaluation to see it as a zero-element list
 // rather than as not set at all.
-func (n *NodeAbstractResource) writeResourceState(ctx EvalContext, addr addrs.AbsResource) error {
+func (n *NodeAbstractResource) writeResourceState(ctx EvalContext, addr addrs.AbsResource) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	state := ctx.State()
 
 	// We'll record our expansion decision in the shared "expander" object
@@ -320,7 +319,7 @@ func (n *NodeAbstractResource) writeResourceState(ctx EvalContext, addr addrs.Ab
 		count, countDiags := evaluateCountExpression(n.Config.Count, ctx)
 		diags = diags.Append(countDiags)
 		if countDiags.HasErrors() {
-			return diags.Err()
+			return diags
 		}
 
 		state.SetResourceProvider(addr, n.ResolvedProvider)
@@ -330,7 +329,7 @@ func (n *NodeAbstractResource) writeResourceState(ctx EvalContext, addr addrs.Ab
 		forEach, forEachDiags := evaluateForEachExpression(n.Config.ForEach, ctx)
 		diags = diags.Append(forEachDiags)
 		if forEachDiags.HasErrors() {
-			return diags.Err()
+			return diags
 		}
 
 		// This method takes care of all of the business logic of updating this
@@ -343,7 +342,7 @@ func (n *NodeAbstractResource) writeResourceState(ctx EvalContext, addr addrs.Ab
 		expander.SetResourceSingle(addr.Module, n.Addr.Resource)
 	}
 
-	return nil
+	return diags
 }
 
 // ReadResourceInstanceState reads the current object for a specific instance in

terraform/node_resource_apply.go

@@ -6,6 +6,7 @@ import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/dag"
 	"github.com/hashicorp/terraform/lang"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // nodeExpandApplyableResource handles the first layer of resource
@@ -102,13 +103,12 @@ func (n *NodeApplyableResource) References() []*addrs.Reference {
 }
 
 // GraphNodeExecutable
-func (n *NodeApplyableResource) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeApplyableResource) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	if n.Config == nil {
 		// Nothing to do, then.
 		log.Printf("[TRACE] NodeApplyableResource: no configuration present for %s", n.Name())
 		return nil
 	}
 
-	err := n.writeResourceState(ctx, n.Addr)
+	return n.writeResourceState(ctx, n.Addr)
-	return err
 }

terraform/node_resource_apply_instance.go

@@ -101,7 +101,7 @@ func (n *NodeApplyableResourceInstance) AttachDependencies(deps []addrs.ConfigRe
 }
 
 // GraphNodeExecutable
-func (n *NodeApplyableResourceInstance) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeApplyableResourceInstance) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	addr := n.ResourceInstanceAddr()
 
 	if n.Config == nil {
@@ -110,7 +110,6 @@ func (n *NodeApplyableResourceInstance) Execute(ctx EvalContext, op walkOperatio
 		//    https://github.com/hashicorp/terraform/issues/21258
 		// To avoid an outright crash here, we'll instead return an explicit
 		// error.
-		var diags tfdiags.Diagnostics
 		diags = diags.Append(tfdiags.Sourceless(
 			tfdiags.Error,
 			"Resource node has no configuration attached",
@@ -119,7 +118,7 @@ func (n *NodeApplyableResourceInstance) Execute(ctx EvalContext, op walkOperatio
 				addr,
 			),
 		))
-		return diags.Err()
+		return diags
 	}
 
 	// Eval info is different depending on what kind of resource this is
@@ -133,22 +132,24 @@ func (n *NodeApplyableResourceInstance) Execute(ctx EvalContext, op walkOperatio
 	}
 }
 
-func (n *NodeApplyableResourceInstance) dataResourceExecute(ctx EvalContext) error {
+func (n *NodeApplyableResourceInstance) dataResourceExecute(ctx EvalContext) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	addr := n.ResourceInstanceAddr().Resource
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	change, err := n.readDiff(ctx, providerSchema)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 	// Stop early if we don't actually have a diff
 	if change == nil {
-		return EvalEarlyExitError{}
+		diags = diags.Append(EvalEarlyExitError{})
+		return diags
 	}
 
 	// In this particular call to EvalReadData we include our planned
@@ -167,9 +168,9 @@ func (n *NodeApplyableResourceInstance) dataResourceExecute(ctx EvalContext) err
 			State:          &state,
 		},
 	}
-	diags = readDataApply.Eval(ctx)
+	diags = diags.Append(readDataApply.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeState := &EvalWriteState{
@@ -178,9 +179,9 @@ func (n *NodeApplyableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		ProviderSchema: &providerSchema,
 		State:          &state,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -188,18 +189,16 @@ func (n *NodeApplyableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		ProviderSchema: &providerSchema,
 		Change:         nil,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	UpdateStateHook(ctx)
+	diags = diags.Append(UpdateStateHook(ctx))
-	return nil
+	return diags
 }
 
-func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext) error {
+func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
-
 	// Declare a bunch of variables that are used for state during
 	// evaluation. Most of this are written to by-address below.
 	var state *states.ResourceInstanceObject
@@ -209,20 +208,23 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 
 	addr := n.ResourceInstanceAddr().Resource
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// Get the saved diff for apply
 	diffApply, err := n.readDiff(ctx, providerSchema)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// We don't want to do any destroys
 	// (these are handled by NodeDestroyResourceInstance instead)
 	if diffApply == nil || diffApply.Action == plans.Delete {
-		return EvalEarlyExitError{}
+		diags = diags.Append(EvalEarlyExitError{})
+		return diags
 	}
 
 	destroy := (diffApply.Action == plans.Delete || diffApply.Action.IsReplace())
@@ -239,9 +241,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 			ForceKey:  n.PreallocatedDeposedKey,
 			OutputKey: &deposedKey,
 		}
-		diags = deposeState.Eval(ctx)
+		diags = diags.Append(deposeState.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 	}
 
@@ -252,15 +254,16 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 
 		Output: &state,
 	}
-	diags = readState.Eval(ctx)
+	diags = diags.Append(readState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Get the saved diff
 	diff, err := n.readDiff(ctx, providerSchema)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// Make a new diff, in case we've learned new values in the state
@@ -277,9 +280,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		OutputChange:   &diffApply,
 		OutputState:    &state,
 	}
-	diags = evalDiff.Eval(ctx)
+	diags = diags.Append(evalDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Compare the diffs
@@ -290,9 +293,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Planned:        &diff,
 		Actual:         &diffApply,
 	}
-	diags = checkPlannedChange.Eval(ctx)
+	diags = diags.Append(checkPlannedChange.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	readState = &EvalReadState{
@@ -302,9 +305,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 
 		Output: &state,
 	}
-	diags = readState.Eval(ctx)
+	diags = diags.Append(readState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	reduceDiff := &EvalReduceDiff{
@@ -313,16 +316,17 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Destroy:   false,
 		OutChange: &diffApply,
 	}
-	diags = reduceDiff.Eval(ctx)
+	diags = diags.Append(reduceDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// EvalReduceDiff may have simplified our planned change
 	// into a NoOp if it only requires destroying, since destroying
 	// is handled by NodeDestroyResourceInstance.
 	if diffApply == nil || diffApply.Action == plans.NoOp {
-		return EvalEarlyExitError{}
+		diags = diags.Append(EvalEarlyExitError{})
+		return diags
 	}
 
 	evalApplyPre := &EvalApplyPre{
@@ -330,9 +334,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State:  &state,
 		Change: &diffApply,
 	}
-	diags = evalApplyPre.Eval(ctx)
+	diags = diags.Append(evalApplyPre.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	var applyError error
@@ -350,9 +354,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		CreateNew:           &createNew,
 		CreateBeforeDestroy: n.CreateBeforeDestroy(),
 	}
-	diags = evalApply.Eval(ctx)
+	diags = diags.Append(evalApply.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// We clear the change out here so that future nodes don't see a change
@@ -362,9 +366,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		ProviderSchema: &providerSchema,
 		Change:         nil,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	evalMaybeTainted := &EvalMaybeTainted{
@@ -373,9 +377,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Change: &diffApply,
 		Error:  &applyError,
 	}
-	diags = evalMaybeTainted.Eval(ctx)
+	diags = diags.Append(evalMaybeTainted.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeState := &EvalWriteState{
@@ -385,9 +389,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State:          &state,
 		Dependencies:   &n.Dependencies,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	applyProvisioners := &EvalApplyProvisioners{
@@ -398,9 +402,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Error:          &applyError,
 		When:           configs.ProvisionerWhenCreate,
 	}
-	diags = applyProvisioners.Eval(ctx)
+	diags = diags.Append(applyProvisioners.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	evalMaybeTainted = &EvalMaybeTainted{
@@ -409,9 +413,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Change: &diffApply,
 		Error:  &applyError,
 	}
-	diags = evalMaybeTainted.Eval(ctx)
+	diags = diags.Append(evalMaybeTainted.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeState = &EvalWriteState{
@@ -421,9 +425,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State:          &state,
 		Dependencies:   &n.Dependencies,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	if createBeforeDestroyEnabled && applyError != nil {
@@ -432,9 +436,9 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 			PlannedChange: &diffApply,
 			Key:           &deposedKey,
 		}
-		diags := maybeRestoreDesposedObject.Eval(ctx)
+		diags := diags.Append(maybeRestoreDesposedObject.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 	}
 
@@ -443,11 +447,11 @@ func (n *NodeApplyableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State: &state,
 		Error: &applyError,
 	}
-	diags = applyPost.Eval(ctx)
+	diags = diags.Append(applyPost.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	UpdateStateHook(ctx)
+	diags = diags.Append(UpdateStateHook(ctx))
-	return nil
+	return diags
 }

terraform/node_resource_apply_test.go

@@ -23,9 +23,9 @@ func TestNodeApplyableResourceExecute(t *testing.T) {
 			},
 			Addr: mustAbsResourceAddr("test_instance.foo"),
 		}
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 		if !state.Empty() {
 			t.Fatalf("expected no state, got:\n %s", state.String())
@@ -48,9 +48,9 @@ func TestNodeApplyableResourceExecute(t *testing.T) {
 			},
 			Addr: mustAbsResourceAddr("test_instance.foo"),
 		}
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 		if state.Empty() {
 			t.Fatal("expected resources in state, got empty state")

terraform/node_resource_destroy.go

@@ -123,9 +123,7 @@ func (n *NodeDestroyResourceInstance) References() []*addrs.Reference {
 }
 
 // GraphNodeExecutable
-func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
-
 	addr := n.ResourceInstanceAddr()
 
 	// Get our state
@@ -140,13 +138,15 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 	var provisionerErr error
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	changeApply, err = n.readDiff(ctx, providerSchema)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	evalReduceDiff := &EvalReduceDiff{
@@ -155,25 +155,28 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 		Destroy:   true,
 		OutChange: &changeApply,
 	}
-	diags = evalReduceDiff.Eval(ctx)
+	diags = diags.Append(evalReduceDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// EvalReduceDiff may have simplified our planned change
 	// into a NoOp if it does not require destroying.
 	if changeApply == nil || changeApply.Action == plans.NoOp {
-		return EvalEarlyExitError{}
+		diags = diags.Append(EvalEarlyExitError{})
+		return diags
 	}
 
 	state, err = n.ReadResourceInstanceState(ctx, addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// Exit early if the state object is null after reading the state
 	if state == nil || state.Value.IsNull() {
-		return EvalEarlyExitError{}
+		diags = diags.Append(EvalEarlyExitError{})
+		return diags
 	}
 
 	evalApplyPre := &EvalApplyPre{
@@ -181,9 +184,9 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 		State:  &state,
 		Change: &changeApply,
 	}
-	diags = evalApplyPre.Eval(ctx)
+	diags = diags.Append(evalApplyPre.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Run destroy provisioners if not tainted
@@ -195,9 +198,9 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 			Error:          &provisionerErr,
 			When:           configs.ProvisionerWhenDestroy,
 		}
-		diags = evalApplyProvisioners.Eval(ctx)
+		diags = diags.Append(evalApplyProvisioners.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 		if provisionerErr != nil {
 			// If we have a provisioning error, then we just call
@@ -207,9 +210,9 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 				State: &state,
 				Error: &provisionerErr,
 			}
-			diags = evalApplyPost.Eval(ctx)
+			diags = diags.Append(evalApplyPost.Eval(ctx))
 			if diags.HasErrors() {
-				return diags.ErrWithWarnings()
+				return diags
 			}
 		}
 	}
@@ -229,9 +232,9 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 			Output:         &state,
 			Error:          &provisionerErr,
 		}
-		diags = evalApply.Eval(ctx)
+		diags = diags.Append(evalApply.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 
 		evalWriteState := &EvalWriteState{
@@ -240,9 +243,9 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 			ProviderSchema: &providerSchema,
 			State:          &state,
 		}
-		diags = evalWriteState.Eval(ctx)
+		diags = diags.Append(evalWriteState.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 	} else {
 		log.Printf("[TRACE] NodeDestroyResourceInstance: removing state object for %s", n.Addr)
@@ -255,15 +258,11 @@ func (n *NodeDestroyResourceInstance) Execute(ctx EvalContext, op walkOperation)
 		State: &state,
 		Error: &provisionerErr,
 	}
-	diags = evalApplyPost.Eval(ctx)
+	diags = diags.Append(evalApplyPost.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	err = UpdateStateHook(ctx)
+	diags = diags.Append(UpdateStateHook(ctx))
-	if err != nil {
+	return diags
-		return err
-	}
-
-	return nil
 }

terraform/node_resource_destroy_deposed.go

@@ -64,14 +64,13 @@ func (n *NodePlanDeposedResourceInstanceObject) References() []*addrs.Reference
 }
 
 // GraphNodeEvalable impl.
-func (n *NodePlanDeposedResourceInstanceObject) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodePlanDeposedResourceInstanceObject) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
-
 	addr := n.ResourceInstanceAddr()
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// During the plan walk we always produce a planned destroy change, because
@@ -86,9 +85,9 @@ func (n *NodePlanDeposedResourceInstanceObject) Execute(ctx EvalContext, op walk
 		Provider:       &provider,
 		ProviderSchema: &providerSchema,
 	}
-	diags = readStateDeposed.Eval(ctx)
+	diags = diags.Append(readStateDeposed.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	diffDestroy := &EvalDiffDestroy{
@@ -98,9 +97,9 @@ func (n *NodePlanDeposedResourceInstanceObject) Execute(ctx EvalContext, op walk
 		State:        &state,
 		Output:       &change,
 	}
-	diags = diffDestroy.Eval(ctx)
+	diags = diags.Append(diffDestroy.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -109,12 +108,8 @@ func (n *NodePlanDeposedResourceInstanceObject) Execute(ctx EvalContext, op walk
 		ProviderSchema: &providerSchema,
 		Change:         &change,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
-	if diags.HasErrors() {
+	return diags
-		return diags.ErrWithWarnings()
-	}
-
-	return nil
 }
 
 // NodeDestroyDeposedResourceInstanceObject represents deposed resource
@@ -184,9 +179,7 @@ func (n *NodeDestroyDeposedResourceInstanceObject) ModifyCreateBeforeDestroy(v b
 }
 
 // GraphNodeExecutable impl.
-func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
-
 	addr := n.ResourceInstanceAddr().Resource
 
 	var state *states.ResourceInstanceObject
@@ -194,8 +187,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 	var applyError error
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	readStateDeposed := &EvalReadStateDeposed{
@@ -205,9 +199,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		Provider:       &provider,
 		ProviderSchema: &providerSchema,
 	}
-	diags = readStateDeposed.Eval(ctx)
+	diags = diags.Append(readStateDeposed.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	diffDestroy := &EvalDiffDestroy{
@@ -216,9 +210,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		State:        &state,
 		Output:       &change,
 	}
-	diags = diffDestroy.Eval(ctx)
+	diags = diags.Append(diffDestroy.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Call pre-apply hook
@@ -227,9 +221,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		State:  &state,
 		Change: &change,
 	}
-	diags = applyPre.Eval(ctx)
+	diags = diags.Append(applyPre.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	apply := &EvalApply{
@@ -243,9 +237,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		Output:         &state,
 		Error:          &applyError,
 	}
-	diags = apply.Eval(ctx)
+	diags = diags.Append(apply.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Always write the resource back to the state deposed. If it
@@ -258,9 +252,9 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		ProviderSchema: &providerSchema,
 		State:          &state,
 	}
-	diags = writeStateDeposed.Eval(ctx)
+	diags = diags.Append(writeStateDeposed.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	applyPost := &EvalApplyPost{
@@ -268,15 +262,16 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		State: &state,
 		Error: &applyError,
 	}
-	diags = applyPost.Eval(ctx)
+	diags = diags.Append(applyPost.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 	if applyError != nil {
-		return applyError
+		diags = diags.Append(applyError)
+		return diags
 	}
-	UpdateStateHook(ctx)
+	diags = diags.Append(UpdateStateHook(ctx))
-	return nil
+	return diags
 }
 
 // GraphNodeDeposer is an optional interface implemented by graph nodes that

terraform/node_resource_plan.go

@@ -178,15 +178,14 @@ func (n *NodePlannableResource) ModuleInstance() addrs.ModuleInstance {
 }
 
 // GraphNodeExecutable
-func (n *NodePlannableResource) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodePlannableResource) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	if n.Config == nil {
 		// Nothing to do, then.
 		log.Printf("[TRACE] NodeApplyableResource: no configuration present for %s", n.Name())
 		return nil
 	}
 
-	err := n.writeResourceState(ctx, n.Addr)
+	return n.writeResourceState(ctx, n.Addr)
-	return err
 }
 
 // GraphNodeDestroyerCBD

terraform/node_resource_plan_destroy.go

@@ -4,6 +4,7 @@ import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/hashicorp/terraform/states"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // NodePlanDestroyableResourceInstance represents a resource that is ready
@@ -32,7 +33,7 @@ func (n *NodePlanDestroyableResourceInstance) DestroyAddr() *addrs.AbsResourceIn
 }
 
 // GraphNodeEvalable
-func (n *NodePlanDestroyableResourceInstance) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodePlanDestroyableResourceInstance) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	addr := n.ResourceInstanceAddr()
 
 	// Declare a bunch of variables that are used for state during
@@ -42,13 +43,15 @@ func (n *NodePlanDestroyableResourceInstance) Execute(ctx EvalContext, op walkOp
 	var state *states.ResourceInstanceObject
 
 	_, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	state, err = n.ReadResourceInstanceState(ctx, addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	diffDestroy := &EvalDiffDestroy{
@@ -57,14 +60,14 @@ func (n *NodePlanDestroyableResourceInstance) Execute(ctx EvalContext, op walkOp
 		State:        &state,
 		Output:       &change,
 	}
-	diags := diffDestroy.Eval(ctx)
+	diags = diags.Append(diffDestroy.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	err = n.checkPreventDestroy(change)
+	diags = diags.Append(n.checkPreventDestroy(change))
-	if err != nil {
+	if diags.HasErrors() {
-		return err
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -72,6 +75,6 @@ func (n *NodePlanDestroyableResourceInstance) Execute(ctx EvalContext, op walkOp
 		ProviderSchema: &providerSchema,
 		Change:         &change,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
-	return diags.ErrWithWarnings()
+	return diags
 }

terraform/node_resource_plan_instance.go

@@ -31,7 +31,7 @@ var (
 )
 
 // GraphNodeEvalable
-func (n *NodePlannableResourceInstance) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodePlannableResourceInstance) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	addr := n.ResourceInstanceAddr()
 
 	// Eval info is different depending on what kind of resource this is
@@ -45,8 +45,7 @@ func (n *NodePlannableResourceInstance) Execute(ctx EvalContext, op walkOperatio
 	}
 }
 
-func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) error {
+func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	config := n.Config
 	addr := n.ResourceInstanceAddr()
 
@@ -54,13 +53,15 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 	var state *states.ResourceInstanceObject
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	state, err = n.ReadResourceInstanceState(ctx, addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	validateSelfRef := &EvalValidateSelfRef{
@@ -68,9 +69,9 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		Config:         config.Config,
 		ProviderSchema: &providerSchema,
 	}
-	diags = validateSelfRef.Eval(ctx)
+	diags = diags.Append(validateSelfRef.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	readDataPlan := &evalReadDataPlan{
@@ -86,9 +87,9 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 			dependsOn:      n.dependsOn,
 		},
 	}
-	diags = readDataPlan.Eval(ctx)
+	diags = diags.Append(readDataPlan.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// write the data source into both the refresh state and the
@@ -100,9 +101,9 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		State:          &state,
 		targetState:    refreshState,
 	}
-	diags = writeRefreshState.Eval(ctx)
+	diags = diags.Append(writeRefreshState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeState := &EvalWriteState{
@@ -111,9 +112,9 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		ProviderSchema: &providerSchema,
 		State:          &state,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -121,12 +122,11 @@ func (n *NodePlannableResourceInstance) dataResourceExecute(ctx EvalContext) err
 		ProviderSchema: &providerSchema,
 		Change:         &change,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
-	return diags.ErrWithWarnings()
+	return diags
 }
 
-func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext) error {
+func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	config := n.Config
 	addr := n.ResourceInstanceAddr()
 
@@ -135,8 +135,9 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 	var instancePlanState *states.ResourceInstanceObject
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	validateSelfRef := &EvalValidateSelfRef{
@@ -144,14 +145,15 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 		Config:         config.Config,
 		ProviderSchema: &providerSchema,
 	}
-	diags = validateSelfRef.Eval(ctx)
+	diags = diags.Append(validateSelfRef.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	instanceRefreshState, err = n.ReadResourceInstanceState(ctx, addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 	refreshLifecycle := &EvalRefreshLifecycle{
 		Addr:                     addr,
@@ -159,9 +161,9 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State:                    &instanceRefreshState,
 		ForceCreateBeforeDestroy: n.ForceCreateBeforeDestroy,
 	}
-	diags = refreshLifecycle.Eval(ctx)
+	diags = diags.Append(refreshLifecycle.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Refresh, maybe
@@ -175,9 +177,9 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 			State:          &instanceRefreshState,
 			Output:         &instanceRefreshState,
 		}
-		diags := refresh.Eval(ctx)
+		diags := diags.Append(refresh.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 
 		writeRefreshState := &EvalWriteState{
@@ -188,9 +190,9 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 			targetState:    refreshState,
 			Dependencies:   &n.Dependencies,
 		}
-		diags = writeRefreshState.Eval(ctx)
+		diags = diags.Append(writeRefreshState.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 	}
 
@@ -207,14 +209,14 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 		OutputChange:        &change,
 		OutputState:         &instancePlanState,
 	}
-	diags = diff.Eval(ctx)
+	diags = diags.Append(diff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	err = n.checkPreventDestroy(change)
+	diags = diags.Append(n.checkPreventDestroy(change))
-	if err != nil {
+	if diags.HasErrors() {
-		return err
+		return diags
 	}
 
 	writeState := &EvalWriteState{
@@ -223,9 +225,9 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 		State:          &instancePlanState,
 		ProviderSchema: &providerSchema,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -233,6 +235,6 @@ func (n *NodePlannableResourceInstance) managedResourceExecute(ctx EvalContext)
 		ProviderSchema: &providerSchema,
 		Change:         &change,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
-	return diags.ErrWithWarnings()
+	return diags
 }

terraform/node_resource_plan_orphan.go

@@ -34,7 +34,7 @@ func (n *NodePlannableResourceInstanceOrphan) Name() string {
 }
 
 // GraphNodeExecutable
-func (n *NodePlannableResourceInstanceOrphan) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodePlannableResourceInstanceOrphan) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	addr := n.ResourceInstanceAddr()
 
 	// Eval info is different depending on what kind of resource this is
@@ -48,7 +48,7 @@ func (n *NodePlannableResourceInstanceOrphan) Execute(ctx EvalContext, op walkOp
 	}
 }
 
-func (n *NodePlannableResourceInstanceOrphan) dataResourceExecute(ctx EvalContext) error {
+func (n *NodePlannableResourceInstanceOrphan) dataResourceExecute(ctx EvalContext) tfdiags.Diagnostics {
 	// A data source that is no longer in the config is removed from the state
 	log.Printf("[TRACE] NodePlannableResourceInstanceOrphan: removing state object for %s", n.Addr)
 	state := ctx.RefreshState()
@@ -56,9 +56,7 @@ func (n *NodePlannableResourceInstanceOrphan) dataResourceExecute(ctx EvalContex
 	return nil
 }
 
-func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalContext) error {
+func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalContext) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
-
 	addr := n.ResourceInstanceAddr()
 
 	// Declare a bunch of variables that are used for state during
@@ -67,13 +65,15 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 	var state *states.ResourceInstanceObject
 
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	state, err = n.ReadResourceInstanceState(ctx, addr)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	if !n.skipRefresh {
@@ -92,9 +92,9 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 			State:          &state,
 			Output:         &state,
 		}
-		diags = refresh.Eval(ctx)
+		diags = diags.Append(refresh.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 
 		writeRefreshState := &EvalWriteState{
@@ -104,9 +104,9 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 			State:          &state,
 			targetState:    refreshState,
 		}
-		diags = writeRefreshState.Eval(ctx)
+		diags = diags.Append(writeRefreshState.Eval(ctx))
 		if diags.HasErrors() {
-			return diags.ErrWithWarnings()
+			return diags
 		}
 	}
 
@@ -117,14 +117,14 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 		Output:       &change,
 		OutputState:  &state, // Will point to a nil state after this complete, signalling destroyed
 	}
-	diags = diffDestroy.Eval(ctx)
+	diags = diags.Append(diffDestroy.Eval(ctx))
-	if err != nil {
+	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
-	err = n.checkPreventDestroy(change)
+	diags = diags.Append(n.checkPreventDestroy(change))
-	if err != nil {
+	if diags.HasErrors() {
-		return err
+		return diags
 	}
 
 	writeDiff := &EvalWriteDiff{
@@ -132,9 +132,9 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 		ProviderSchema: &providerSchema,
 		Change:         &change,
 	}
-	diags = writeDiff.Eval(ctx)
+	diags = diags.Append(writeDiff.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	writeState := &EvalWriteState{
@@ -143,9 +143,6 @@ func (n *NodePlannableResourceInstanceOrphan) managedResourceExecute(ctx EvalCon
 		ProviderSchema: &providerSchema,
 		State:          &state,
 	}
-	diags = writeState.Eval(ctx)
+	diags = diags.Append(writeState.Eval(ctx))
-	if diags.HasErrors() {
+	return diags
-		return diags.ErrWithWarnings()
-	}
-	return nil
 }

terraform/node_resource_plan_orphan_test.go

@@ -55,9 +55,9 @@ func TestNodeResourcePlanOrphanExecute(t *testing.T) {
 			Addr: mustResourceInstanceAddr("test_object.foo"),
 		},
 	}
-	err := node.Execute(ctx, walkApply)
+	diags := node.Execute(ctx, walkApply)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("unexpected error: %s", err.Error())
+		t.Fatalf("unexpected error: %s", diags.Err())
 	}
 	if !state.Empty() {
 		t.Fatalf("expected empty state, got %s", state.String())

terraform/node_resource_plan_test.go

@@ -23,9 +23,9 @@ func TestNodePlannableResourceExecute(t *testing.T) {
 			},
 			Addr: mustAbsResourceAddr("test_instance.foo"),
 		}
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 		if !state.Empty() {
 			t.Fatalf("expected no state, got:\n %s", state.String())
@@ -48,9 +48,9 @@ func TestNodePlannableResourceExecute(t *testing.T) {
 			},
 			Addr: mustAbsResourceAddr("test_instance.foo"),
 		}
-		err := node.Execute(ctx, walkApply)
+		diags := node.Execute(ctx, walkApply)
-		if err != nil {
+		if diags.HasErrors() {
-			t.Fatalf("unexpected error: %s", err.Error())
+			t.Fatalf("unexpected error: %s", diags.Err())
 		}
 		if state.Empty() {
 			t.Fatal("expected resources in state, got empty state")

terraform/node_resource_validate.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
+	"github.com/hashicorp/terraform/tfdiags"
 	"github.com/zclconf/go-cty/cty"
 )
 
@@ -31,7 +32,7 @@ func (n *NodeValidatableResource) Path() addrs.ModuleInstance {
 }
 
 // GraphNodeEvalable
-func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	addr := n.ResourceAddr()
 	config := n.Config
 
@@ -40,8 +41,9 @@ func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) err
 	// passed to the EvalNodes.
 	var configVal cty.Value
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	evalValidateResource := &EvalValidateResource{
@@ -52,9 +54,9 @@ func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) err
 		Config:         config,
 		ConfigVal:      &configVal,
 	}
-	err = evalValidateResource.Validate(ctx)
+	diags = diags.Append(evalValidateResource.Validate(ctx))
-	if err != nil {
+	if diags.HasErrors() {
-		return err
+		return diags
 	}
 
 	if managed := n.Config.Managed; managed != nil {
@@ -71,11 +73,13 @@ func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) err
 
 			provisioner := ctx.Provisioner(p.Type)
 			if provisioner == nil {
-				return fmt.Errorf("provisioner %s not initialized", p.Type)
+				diags = diags.Append(fmt.Errorf("provisioner %s not initialized", p.Type))
+				return diags
 			}
 			provisionerSchema := ctx.ProvisionerSchema(p.Type)
 			if provisionerSchema == nil {
-				return fmt.Errorf("provisioner %s not initialized", p.Type)
+				diags = diags.Append(fmt.Errorf("provisioner %s not initialized", p.Type))
+				return diags
 			}
 
 			// Validate Provisioner Config
@@ -87,11 +91,11 @@ func (n *NodeValidatableResource) Execute(ctx EvalContext, op walkOperation) err
 				ResourceHasCount:   hasCount,
 				ResourceHasForEach: hasForEach,
 			}
-			err := validateProvisioner.Validate(ctx)
+			diags = diags.Append(validateProvisioner.Validate(ctx))
-			if err != nil {
+			if diags.HasErrors() {
-				return err
+				return diags
 			}
 		}
 	}
-	return nil
+	return diags
 }

terraform/node_root_variable.go

@@ -4,6 +4,7 @@ import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
 	"github.com/hashicorp/terraform/dag"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // NodeRootVariable represents a root variable input.
@@ -36,7 +37,7 @@ func (n *NodeRootVariable) ReferenceableAddrs() []addrs.Referenceable {
 }
 
 // GraphNodeExecutable
-func (n *NodeRootVariable) Execute(ctx EvalContext, op walkOperation) error {
+func (n *NodeRootVariable) Execute(ctx EvalContext, op walkOperation) tfdiags.Diagnostics {
 	// We don't actually need to _evaluate_ a root module variable, because
 	// its value is always constant and already stashed away in our EvalContext.
 	// However, we might need to run some user-defined validation rules against

terraform/node_root_variable_test.go

@@ -17,9 +17,9 @@ func TestNodeRootVariableExecute(t *testing.T) {
 		},
 	}
 
-	err := n.Execute(ctx, walkApply)
+	diags := n.Execute(ctx, walkApply)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("unexpected error: %s", err.Error())
+		t.Fatalf("unexpected error: %s", diags.Err())
 	}
 
 }

terraform/transform_import_state.go

@@ -116,25 +116,25 @@ func (n *graphNodeImportState) ModulePath() addrs.Module {
 }
 
 // GraphNodeExecutable impl.
-func (n *graphNodeImportState) Execute(ctx EvalContext, op walkOperation) error {
+func (n *graphNodeImportState) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
 	// Reset our states
 	n.states = nil
 
 	provider, _, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// import state
 	absAddr := n.Addr.Resource.Absolute(ctx.Path())
-	var diags tfdiags.Diagnostics
 
 	// Call pre-import hook
-	err = ctx.Hook(func(h Hook) (HookAction, error) {
+	diags = diags.Append(ctx.Hook(func(h Hook) (HookAction, error) {
 		return h.PreImportState(absAddr, n.ID)
-	})
+	}))
-	if err != nil {
+	if diags.HasErrors() {
-		return err
+		return diags
 	}
 
 	resp := provider.ImportResourceState(providers.ImportResourceStateRequest{
@@ -143,7 +143,7 @@ func (n *graphNodeImportState) Execute(ctx EvalContext, op walkOperation) error
 	})
 	diags = diags.Append(resp.Diagnostics)
 	if diags.HasErrors() {
-		return diags.Err()
+		return diags
 	}
 
 	imported := resp.ImportedResources
@@ -153,10 +153,10 @@ func (n *graphNodeImportState) Execute(ctx EvalContext, op walkOperation) error
 	n.states = imported
 
 	// Call post-import hook
-	err = ctx.Hook(func(h Hook) (HookAction, error) {
+	diags = diags.Append(ctx.Hook(func(h Hook) (HookAction, error) {
 		return h.PostImportState(absAddr, imported)
-	})
+	}))
-	return err
+	return diags
 }
 
 // GraphNodeDynamicExpandable impl.
@@ -259,17 +259,18 @@ func (n *graphNodeImportStateSub) Path() addrs.ModuleInstance {
 }
 
 // GraphNodeExecutable impl.
-func (n *graphNodeImportStateSub) Execute(ctx EvalContext, op walkOperation) error {
+func (n *graphNodeImportStateSub) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	var diags tfdiags.Diagnostics
 	// If the Ephemeral type isn't set, then it is an error
 	if n.State.TypeName == "" {
-		return fmt.Errorf("import of %s didn't set type", n.TargetAddr.String())
+		diags = diags.Append(fmt.Errorf("import of %s didn't set type", n.TargetAddr.String()))
+		return diags
 	}
 
 	state := n.State.AsInstanceObject()
 	provider, providerSchema, err := GetProvider(ctx, n.ResolvedProvider)
-	if err != nil {
+	diags = diags.Append(err)
-		return err
+	if diags.HasErrors() {
+		return diags
 	}
 
 	// EvalRefresh
@@ -281,9 +282,9 @@ func (n *graphNodeImportStateSub) Execute(ctx EvalContext, op walkOperation) err
 		State:          &state,
 		Output:         &state,
 	}
-	diags = evalRefresh.Eval(ctx)
+	diags = diags.Append(evalRefresh.Eval(ctx))
 	if diags.HasErrors() {
-		return diags.ErrWithWarnings()
+		return diags
 	}
 
 	// Verify the existance of the imported resource
@@ -296,7 +297,7 @@ func (n *graphNodeImportStateSub) Execute(ctx EvalContext, op walkOperation) err
 				n.TargetAddr.Resource.String(),
 			),
 		))
-		return diags.Err()
+		return diags
 	}
 
 	//EvalWriteState
@@ -307,5 +308,5 @@ func (n *graphNodeImportStateSub) Execute(ctx EvalContext, op walkOperation) err
 		State:          &state,
 	}
 	diags = diags.Append(evalWriteState.Eval(ctx))
-	return diags.ErrWithWarnings()
+	return diags
 }

terraform/transform_import_state_test.go

@@ -41,9 +41,9 @@ func TestGraphNodeImportStateExecute(t *testing.T) {
 		},
 	}
 
-	err := node.Execute(ctx, walkImport)
+	diags := node.Execute(ctx, walkImport)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("Unexpected error: %s", err.Error())
+		t.Fatalf("Unexpected error: %s", diags.Err())
 	}
 
 	if len(node.states) != 1 {
@@ -93,9 +93,9 @@ func TestGraphNodeImportStateSubExecute(t *testing.T) {
 			Module:   addrs.RootModule,
 		},
 	}
-	err := node.Execute(ctx, walkImport)
+	diags := node.Execute(ctx, walkImport)
-	if err != nil {
+	if diags.HasErrors() {
-		t.Fatalf("Unexpected error: %s", err.Error())
+		t.Fatalf("Unexpected error: %s", diags.Err())
 	}
 
 	// check for resource in state

terraform/transform_provider.go

@@ -449,6 +449,7 @@ type graphNodeCloseProvider struct {
 
 var (
 	_ GraphNodeCloseProvider = (*graphNodeCloseProvider)(nil)
+	_ GraphNodeExecutable    = (*graphNodeCloseProvider)(nil)
 )
 
 func (n *graphNodeCloseProvider) Name() string {
@@ -461,8 +462,8 @@ func (n *graphNodeCloseProvider) ModulePath() addrs.Module {
 }
 
 // GraphNodeExecutable impl.
-func (n *graphNodeCloseProvider) Execute(ctx EvalContext, op walkOperation) error {
+func (n *graphNodeCloseProvider) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	return ctx.CloseProvider(n.Addr)
+	return diags.Append(ctx.CloseProvider(n.Addr))
 }
 
 // GraphNodeDependable impl.

terraform/transform_provisioner.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/terraform/dag"
+	"github.com/hashicorp/terraform/tfdiags"
 )
 
 // GraphNodeProvisioner is an interface that nodes that can be a provisioner
@@ -165,13 +166,15 @@ type graphNodeCloseProvisioner struct {
 	ProvisionerNameValue string
 }
 
+var _ GraphNodeExecutable = (*graphNodeCloseProvisioner)(nil)
+
 func (n *graphNodeCloseProvisioner) Name() string {
 	return fmt.Sprintf("provisioner.%s (close)", n.ProvisionerNameValue)
 }
 
 // GraphNodeExecutable impl.
-func (n *graphNodeCloseProvisioner) Execute(ctx EvalContext, op walkOperation) error {
+func (n *graphNodeCloseProvisioner) Execute(ctx EvalContext, op walkOperation) (diags tfdiags.Diagnostics) {
-	return ctx.CloseProvisioner(n.ProvisionerNameValue)
+	return diags.Append(ctx.CloseProvisioner(n.ProvisionerNameValue))
 }
 
 func (n *graphNodeCloseProvisioner) CloseProvisionerName() string {