rename and cleanup use of count/for_each eval func

Stop evaluating count and for each if they aren't set in the config.
Remove "Resource" from the function names, as they are also now used
with modules.

terraform/eval_apply.go

@@ -61,7 +61,7 @@ func (n *EvalApply) Eval(ctx EvalContext) (interface{}, error) {
 	configVal := cty.NullVal(cty.DynamicPseudoType)
 	if n.Config != nil {
 		var configDiags tfdiags.Diagnostics
-		forEach, _ := evaluateResourceForEachExpression(n.Config.ForEach, ctx)
+		forEach, _ := evaluateForEachExpression(n.Config.ForEach, ctx)
 		keyData := EvalDataForInstanceKey(n.Addr.Key, forEach)
 		configVal, _, configDiags = ctx.EvaluateBlock(n.Config.Config, schema, nil, keyData)
 		diags = diags.Append(configDiags)
@@ -595,7 +595,7 @@ func (n *EvalApplyProvisioners) apply(ctx EvalContext, provs []*configs.Provisio
 		// in its result. That's okay because each.value is prohibited for
 		// destroy-time provisioners.
 		if n.When != configs.ProvisionerWhenDestroy {
-			m, forEachDiags := evaluateResourceForEachExpression(n.ResourceConfig.ForEach, ctx)
+			m, forEachDiags := evaluateForEachExpression(n.ResourceConfig.ForEach, ctx)
 			diags = diags.Append(forEachDiags)
 			forEach = m
 		}

terraform/eval_count.go

@@ -11,7 +11,7 @@ import (
 	"github.com/zclconf/go-cty/cty/gocty"
 )
 
-// evaluateResourceCountExpression is our standard mechanism for interpreting an
+// evaluateCountExpression is our standard mechanism for interpreting an
 // expression given for a "count" argument on a resource. This should be called
 // from the DynamicExpand of a node representing a resource in order to
 // determine the final count value.
@@ -24,9 +24,9 @@ import (
 //
 // If error diagnostics are returned then the result is always the meaningless
 // placeholder value -1.
-func evaluateResourceCountExpression(expr hcl.Expression, ctx EvalContext) (int, tfdiags.Diagnostics) {
-	count, known, diags := evaluateResourceCountExpressionKnown(expr, ctx)
-	if !known {
+func evaluateCountExpression(expr hcl.Expression, ctx EvalContext) (int, tfdiags.Diagnostics) {
+	countVal, diags := evaluateCountExpressionValue(expr, ctx)
+	if !countVal.IsKnown() {
 		// Currently this is a rather bad outcome from a UX standpoint, since we have
 		// no real mechanism to deal with this situation and all we can do is produce
 		// an error message.
@@ -40,22 +40,29 @@ func evaluateResourceCountExpression(expr hcl.Expression, ctx EvalContext) (int,
 			Subject:  expr.Range().Ptr(),
 		})
 	}
-	return count, diags
+
+	if countVal.IsNull() || !countVal.IsKnown() {
+		return -1, diags
+	}
+
+	count, _ := countVal.AsBigFloat().Int64()
+	return int(count), diags
 }
 
-// evaluateResourceCountExpressionKnown is like evaluateResourceCountExpression
-// except that it handles an unknown result by returning count = 0 and
-// a known = false, rather than by reporting the unknown value as an error
-// diagnostic.
-func evaluateResourceCountExpressionKnown(expr hcl.Expression, ctx EvalContext) (count int, known bool, diags tfdiags.Diagnostics) {
+// evaluateCountExpressionValue is like evaluateCountExpression
+// except that it returns a cty.Value which must be a cty.Number and can be
+// unknown.
+func evaluateCountExpressionValue(expr hcl.Expression, ctx EvalContext) (cty.Value, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+	nullCount := cty.NullVal(cty.Number)
 	if expr == nil {
-		return -1, true, nil
+		return nullCount, nil
 	}
 
 	countVal, countDiags := ctx.EvaluateExpr(expr, cty.Number, nil)
 	diags = diags.Append(countDiags)
 	if diags.HasErrors() {
-		return -1, true, diags
+		return nullCount, diags
 	}
 
 	switch {
@@ -66,11 +73,13 @@ func evaluateResourceCountExpressionKnown(expr hcl.Expression, ctx EvalContext)
 			Detail:   `The given "count" argument value is null. An integer is required.`,
 			Subject:  expr.Range().Ptr(),
 		})
-		return -1, true, diags
+		return nullCount, diags
+
 	case !countVal.IsKnown():
-		return 0, false, diags
+		return cty.UnknownVal(cty.Number), diags
 	}
 
+	var count int
 	err := gocty.FromCtyValue(countVal, &count)
 	if err != nil {
 		diags = diags.Append(&hcl.Diagnostic{
@@ -79,7 +88,7 @@ func evaluateResourceCountExpressionKnown(expr hcl.Expression, ctx EvalContext)
 			Detail:   fmt.Sprintf(`The given "count" argument value is unsuitable: %s.`, err),
 			Subject:  expr.Range().Ptr(),
 		})
-		return -1, true, diags
+		return nullCount, diags
 	}
 	if count < 0 {
 		diags = diags.Append(&hcl.Diagnostic{
@@ -88,10 +97,10 @@ func evaluateResourceCountExpressionKnown(expr hcl.Expression, ctx EvalContext)
 			Detail:   `The given "count" argument value is unsuitable: negative numbers are not supported.`,
 			Subject:  expr.Range().Ptr(),
 		})
-		return -1, true, diags
+		return nullCount, diags
 	}
 
-	return count, true, diags
+	return countVal, diags
 }
 
 // fixResourceCountSetTransition is a helper function to fix up the state when a
@@ -101,7 +110,7 @@ func evaluateResourceCountExpressionKnown(expr hcl.Expression, ctx EvalContext)
 //
 // The correct time to call this function is in the DynamicExpand method for
 // a node representing a resource, just after evaluating the count with
-// evaluateResourceCountExpression, and before any other analysis of the
+// evaluateCountExpression, and before any other analysis of the
 // state such as orphan detection.
 //
 // This function calls methods on the given EvalContext to update the current

terraform/eval_diff.go

@@ -133,7 +133,7 @@ func (n *EvalDiff) Eval(ctx EvalContext) (interface{}, error) {
 		// Should be caught during validation, so we don't bother with a pretty error here
 		return nil, fmt.Errorf("provider does not support resource type %q", n.Addr.Resource.Type)
 	}
-	forEach, _ := evaluateResourceForEachExpression(n.Config.ForEach, ctx)
+	forEach, _ := evaluateForEachExpression(n.Config.ForEach, ctx)
 	keyData := EvalDataForInstanceKey(n.Addr.Key, forEach)
 	configVal, _, configDiags := ctx.EvaluateBlock(config.Config, schema, nil, keyData)
 	diags = diags.Append(configDiags)

terraform/eval_for_each.go

@@ -8,14 +8,14 @@ import (
 	"github.com/zclconf/go-cty/cty"
 )
 
-// evaluateResourceForEachExpression interprets a "for_each" argument on a resource.
+// evaluateForEachExpression interprets a "for_each" argument on a resource.
 //
 // Returns a cty.Value map, and diagnostics if necessary. It will return nil if
 // the expression is nil, and is used to distinguish between an unset for_each and an
 // empty map
-func evaluateResourceForEachExpression(expr hcl.Expression, ctx EvalContext) (forEach map[string]cty.Value, diags tfdiags.Diagnostics) {
-	forEachMap, known, diags := evaluateResourceForEachExpressionKnown(expr, ctx)
-	if !known {
+func evaluateForEachExpression(expr hcl.Expression, ctx EvalContext) (forEach map[string]cty.Value, diags tfdiags.Diagnostics) {
+	forEachVal, diags := evaluateForEachExpressionValue(expr, ctx)
+	if !forEachVal.IsKnown() {
 		// Attach a diag as we do with count, with the same downsides
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity: hcl.DiagError,
@@ -24,23 +24,31 @@ func evaluateResourceForEachExpression(expr hcl.Expression, ctx EvalContext) (fo
 			Subject:  expr.Range().Ptr(),
 		})
 	}
-	return forEachMap, diags
+
+	if forEachVal.IsNull() || !forEachVal.IsKnown() || forEachVal.LengthInt() == 0 {
+		// we check length, because an empty set return a nil map
+		return map[string]cty.Value{}, diags
+	}
+
+	return forEachVal.AsValueMap(), diags
 }
 
-// evaluateResourceForEachExpressionKnown is like evaluateResourceForEachExpression
-// except that it handles an unknown result by returning an empty map and
-// a known = false, rather than by reporting the unknown value as an error
-// diagnostic.
-func evaluateResourceForEachExpressionKnown(expr hcl.Expression, ctx EvalContext) (forEach map[string]cty.Value, known bool, diags tfdiags.Diagnostics) {
+// evaluateForEachExpressionValue is like evaluateForEachExpression
+// except that it returns a cty.Value map or set which can be unknown.
+func evaluateForEachExpressionValue(expr hcl.Expression, ctx EvalContext) (cty.Value, tfdiags.Diagnostics) {
+	var diags tfdiags.Diagnostics
+	nullMap := cty.NullVal(cty.Map(cty.DynamicPseudoType))
+
 	if expr == nil {
-		return nil, true, nil
+		return nullMap, diags
 	}
 
 	forEachVal, forEachDiags := ctx.EvaluateExpr(expr, cty.DynamicPseudoType, nil)
 	diags = diags.Append(forEachDiags)
 	if diags.HasErrors() {
-		return nil, true, diags
+		return nullMap, diags
 	}
+	ty := forEachVal.Type()
 
 	switch {
 	case forEachVal.IsNull():
@@ -50,44 +58,42 @@ func evaluateResourceForEachExpressionKnown(expr hcl.Expression, ctx EvalContext
 			Detail:   `The given "for_each" argument value is unsuitable: the given "for_each" argument value is null. A map, or set of strings is allowed.`,
 			Subject:  expr.Range().Ptr(),
 		})
-		return nil, true, diags
+		return nullMap, diags
 	case !forEachVal.IsKnown():
-		return map[string]cty.Value{}, false, diags
-	}
+		// ensure that we have a map, and not a DynamicValue
+		return cty.UnknownVal(cty.Map(cty.DynamicPseudoType)), diags
 
-	if !forEachVal.CanIterateElements() || forEachVal.Type().IsListType() || forEachVal.Type().IsTupleType() {
+	case !(ty.IsMapType() || ty.IsSetType() || ty.IsObjectType()):
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity: hcl.DiagError,
 			Summary:  "Invalid for_each argument",
-			Detail:   fmt.Sprintf(`The given "for_each" argument value is unsuitable: the "for_each" argument must be a map, or set of strings, and you have provided a value of type %s.`, forEachVal.Type().FriendlyName()),
+			Detail:   fmt.Sprintf(`The given "for_each" argument value is unsuitable: the "for_each" argument must be a map, or set of strings, and you have provided a value of type %s.`, ty.FriendlyName()),
 			Subject:  expr.Range().Ptr(),
 		})
-		return nil, true, diags
+		return nullMap, diags
+
+	case forEachVal.LengthInt() == 0:
+		// If the map is empty ({}), return an empty map, because cty will
+		// return nil when representing {} AsValueMap This also covers an empty
+		// set (toset([]))
+		return forEachVal, diags
 	}
 
-	// If the map is empty ({}), return an empty map, because cty will return nil when representing {} AsValueMap
-	// This also covers an empty set (toset([]))
-	if forEachVal.LengthInt() == 0 {
-		return map[string]cty.Value{}, true, diags
-	}
-
-	if forEachVal.Type().IsSetType() {
-		if forEachVal.Type().ElementType() != cty.String {
+	if ty.IsSetType() {
+		if ty.ElementType() != cty.String {
 			diags = diags.Append(&hcl.Diagnostic{
 				Severity: hcl.DiagError,
 				Summary:  "Invalid for_each set argument",
 				Detail:   fmt.Sprintf(`The given "for_each" argument value is unsuitable: "for_each" supports maps and sets of strings, but you have provided a set containing type %s.`, forEachVal.Type().ElementType().FriendlyName()),
 				Subject:  expr.Range().Ptr(),
 			})
-			return nil, true, diags
+			return cty.NullVal(ty), diags
 		}
 
-		// A set may contain unknown values that must be
-		// discovered by checking with IsWhollyKnown (which iterates through the
-		// structure), while for maps in cty, keys can never be unknown or null,
-		// thus the earlier IsKnown check suffices for maps
+		// since we can't use a set values that are unknown, we treat the
+		// entire set as unknown
 		if !forEachVal.IsWhollyKnown() {
-			return map[string]cty.Value{}, false, diags
+			return cty.UnknownVal(ty), diags
 		}
 
 		// A set of strings may contain null, which makes it impossible to
@@ -102,10 +108,10 @@ func evaluateResourceForEachExpressionKnown(expr hcl.Expression, ctx EvalContext
 					Detail:   fmt.Sprintf(`The given "for_each" argument value is unsuitable: "for_each" sets must not contain null values.`),
 					Subject:  expr.Range().Ptr(),
 				})
-				return nil, true, diags
+				return cty.NullVal(ty), diags
 			}
 		}
 	}
 
-	return forEachVal.AsValueMap(), true, nil
+	return forEachVal, nil
 }

terraform/eval_for_each_test.go

@@ -12,7 +12,7 @@ import (
 	"github.com/zclconf/go-cty/cty"
 )
 
-func TestEvaluateResourceForEachExpression_valid(t *testing.T) {
+func TestEvaluateForEachExpression_valid(t *testing.T) {
 	tests := map[string]struct {
 		Expr       hcl.Expression
 		ForEachMap map[string]cty.Value
@@ -58,7 +58,7 @@ func TestEvaluateResourceForEachExpression_valid(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			ctx := &MockEvalContext{}
 			ctx.installSimpleEval()
-			forEachMap, diags := evaluateResourceForEachExpression(test.Expr, ctx)
+			forEachMap, diags := evaluateForEachExpression(test.Expr, ctx)
 
 			if len(diags) != 0 {
 				t.Errorf("unexpected diagnostics %s", spew.Sdump(diags))
@@ -75,7 +75,7 @@ func TestEvaluateResourceForEachExpression_valid(t *testing.T) {
 	}
 }
 
-func TestEvaluateResourceForEachExpression_errors(t *testing.T) {
+func TestEvaluateForEachExpression_errors(t *testing.T) {
 	tests := map[string]struct {
 		Expr                     hcl.Expression
 		Summary, DetailSubstring string
@@ -131,7 +131,7 @@ func TestEvaluateResourceForEachExpression_errors(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			ctx := &MockEvalContext{}
 			ctx.installSimpleEval()
-			_, diags := evaluateResourceForEachExpression(test.Expr, ctx)
+			_, diags := evaluateForEachExpression(test.Expr, ctx)
 
 			if len(diags) != 1 {
 				t.Fatalf("got %d diagnostics; want 1", diags)
@@ -149,7 +149,7 @@ func TestEvaluateResourceForEachExpression_errors(t *testing.T) {
 	}
 }
 
-func TestEvaluateResourceForEachExpressionKnown(t *testing.T) {
+func TestEvaluateForEachExpressionKnown(t *testing.T) {
 	tests := map[string]hcl.Expression{
 		"unknown string set": hcltest.MockExprLiteral(cty.UnknownVal(cty.Set(cty.String))),
 		"unknown map":        hcltest.MockExprLiteral(cty.UnknownVal(cty.Map(cty.Bool))),
@@ -159,23 +159,15 @@ func TestEvaluateResourceForEachExpressionKnown(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			ctx := &MockEvalContext{}
 			ctx.installSimpleEval()
-			forEachMap, known, diags := evaluateResourceForEachExpressionKnown(expr, ctx)
+			forEachVal, diags := evaluateForEachExpressionValue(expr, ctx)
 
 			if len(diags) != 0 {
 				t.Errorf("unexpected diagnostics %s", spew.Sdump(diags))
 			}
 
-			if known {
-				t.Errorf("got %v known, want false", known)
+			if forEachVal.IsKnown() {
+				t.Error("got known, want unknown")
 			}
-
-			if len(forEachMap) != 0 {
-				t.Errorf(
-					"expected empty map\ngot:  %s",
-					spew.Sdump(forEachMap),
-				)
-			}
-
 		})
 	}
 }

terraform/eval_read_data.go

@@ -96,7 +96,7 @@ func (n *EvalReadData) Eval(ctx EvalContext) (interface{}, error) {
 	objTy := schema.ImpliedType()
 	priorVal := cty.NullVal(objTy) // for data resources, prior is always null because we start fresh every time
 
-	forEach, _ := evaluateResourceForEachExpression(n.Config.ForEach, ctx)
+	forEach, _ := evaluateForEachExpression(n.Config.ForEach, ctx)
 	keyData := EvalDataForInstanceKey(n.Addr.Key, forEach)
 
 	var configDiags tfdiags.Diagnostics

terraform/eval_state.go

@@ -466,36 +466,32 @@ func (n *EvalWriteResourceState) Eval(ctx EvalContext) (interface{}, error) {
 	// can refer to it. Since this node represents the abstract module, we need
 	// to expand the module here to create all resources.
 	expander := ctx.InstanceExpander()
-	count, countDiags := evaluateResourceCountExpression(n.Config.Count, ctx)
+
+	switch {
+	case n.Config.Count != nil:
+		count, countDiags := evaluateCountExpression(n.Config.Count, ctx)
 		diags = diags.Append(countDiags)
 		if countDiags.HasErrors() {
 			return nil, diags.Err()
 		}
 
-	eachMode := states.NoEach
-	if count >= 0 { // -1 signals "count not set"
-		eachMode = states.EachList
-	}
+		state.SetResourceMeta(n.Addr, states.EachList, n.ProviderAddr)
+		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, count)
 
-	forEach, forEachDiags := evaluateResourceForEachExpression(n.Config.ForEach, ctx)
+	case n.Config.ForEach != nil:
+		forEach, forEachDiags := evaluateForEachExpression(n.Config.ForEach, ctx)
 		diags = diags.Append(forEachDiags)
 		if forEachDiags.HasErrors() {
 			return nil, diags.Err()
 		}
 
-	if forEach != nil {
-		eachMode = states.EachMap
-	}
 		// This method takes care of all of the business logic of updating this
 		// while ensuring that any existing instances are preserved, etc.
-	state.SetResourceMeta(n.Addr, eachMode, n.ProviderAddr)
-
-	switch eachMode {
-	case states.EachList:
-		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, count)
-	case states.EachMap:
+		state.SetResourceMeta(n.Addr, states.EachMap, n.ProviderAddr)
 		expander.SetResourceForEach(n.Addr.Module, n.Addr.Resource, forEach)
+
 	default:
+		state.SetResourceMeta(n.Addr, states.NoEach, n.ProviderAddr)
 		expander.SetResourceSingle(n.Addr.Module, n.Addr.Resource)
 	}
 

terraform/eval_validate.go

@@ -375,7 +375,9 @@ func (n *EvalValidateResource) Eval(ctx EvalContext) (interface{}, error) {
 	mode := cfg.Mode
 
 	keyData := EvalDataForNoInstanceKey
-	if n.Config.Count != nil {
+
+	switch {
+	case n.Config.Count != nil:
 		// If the config block has count, we'll evaluate with an unknown
 		// number as count.index so we can still type check even though
 		// we won't expand count until the plan phase.
@@ -387,9 +389,8 @@ func (n *EvalValidateResource) Eval(ctx EvalContext) (interface{}, error) {
 		// of this will happen when we DynamicExpand during the plan walk.
 		countDiags := n.validateCount(ctx, n.Config.Count)
 		diags = diags.Append(countDiags)
-	}
 
-	if n.Config.ForEach != nil {
+	case n.Config.ForEach != nil:
 		keyData = InstanceKeyEvalData{
 			EachKey:   cty.UnknownVal(cty.String),
 			EachValue: cty.UnknownVal(cty.DynamicPseudoType),
@@ -608,10 +609,10 @@ func (n *EvalValidateResource) validateCount(ctx EvalContext, expr hcl.Expressio
 }
 
 func (n *EvalValidateResource) validateForEach(ctx EvalContext, expr hcl.Expression) (diags tfdiags.Diagnostics) {
-	_, known, forEachDiags := evaluateResourceForEachExpressionKnown(expr, ctx)
+	val, forEachDiags := evaluateForEachExpressionValue(expr, ctx)
 	// If the value isn't known then that's the best we can do for now, but
 	// we'll check more thoroughly during the plan walk
-	if !known {
+	if !val.IsKnown() {
 		return diags
 	}
 

terraform/node_data_refresh.go

@@ -65,43 +65,46 @@ func (n *NodeRefreshableDataResource) Path() addrs.ModuleInstance {
 func (n *NodeRefreshableDataResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
 	var diags tfdiags.Diagnostics
 
-	count, countKnown, countDiags := evaluateResourceCountExpressionKnown(n.Config.Count, ctx)
+	expander := ctx.InstanceExpander()
+
+	switch {
+	case n.Config.Count != nil:
+		count, countDiags := evaluateCountExpressionValue(n.Config.Count, ctx)
 		diags = diags.Append(countDiags)
 		if countDiags.HasErrors() {
 			return nil, diags.Err()
 		}
-	if !countKnown {
+		if !count.IsKnown() {
 			// If the count isn't known yet, we'll skip refreshing and try expansion
 			// again during the plan walk.
 			return nil, nil
 		}
 
-	forEachMap, forEachKnown, forEachDiags := evaluateResourceForEachExpressionKnown(n.Config.ForEach, ctx)
+		c, _ := count.AsBigFloat().Int64()
+		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, int(c))
+
+	case n.Config.ForEach != nil:
+		forEachVal, forEachDiags := evaluateForEachExpressionValue(n.Config.ForEach, ctx)
 		diags = diags.Append(forEachDiags)
 		if forEachDiags.HasErrors() {
 			return nil, diags.Err()
 		}
-	if !forEachKnown {
+		if !forEachVal.IsKnown() {
 			// If the for_each isn't known yet, we'll skip refreshing and try expansion
 			// again during the plan walk.
 			return nil, nil
 		}
 
-	// Next we need to potentially rename an instance address in the state
-	// if we're transitioning whether "count" is set at all.
-	fixResourceCountSetTransition(ctx, n.ResourceAddr(), count != -1)
+		expander.SetResourceForEach(n.Addr.Module, n.Addr.Resource, forEachVal.AsValueMap())
 
-	// Inform our instance expander about our expansion results above,
-	// and then use it to calculate the instance addresses we'll expand for.
-	expander := ctx.InstanceExpander()
-	switch {
-	case count >= 0:
-		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, count)
-	case forEachMap != nil:
-		expander.SetResourceForEach(n.Addr.Module, n.Addr.Resource, forEachMap)
 	default:
 		expander.SetResourceSingle(n.Addr.Module, n.Addr.Resource)
 	}
+
+	// Next we need to potentially rename an instance address in the state
+	// if we're transitioning whether "count" is set at all.
+	fixResourceCountSetTransition(ctx, n.ResourceAddr(), n.Config.Count != nil)
+
 	instanceAddrs := expander.ExpandResource(n.Addr)
 
 	// Our graph transformers require access to the full state, so we'll

terraform/node_module_expand.go

@@ -229,14 +229,14 @@ func (n *evalPrepareModuleExpansion) Eval(ctx EvalContext) (interface{}, error)
 
 		switch {
 		case n.ModuleCall.Count != nil:
-			count, diags := evaluateResourceCountExpression(n.ModuleCall.Count, ctx)
+			count, diags := evaluateCountExpression(n.ModuleCall.Count, ctx)
 			if diags.HasErrors() {
 				return nil, diags.Err()
 			}
 			expander.SetModuleCount(module, call, count)
 
 		case n.ModuleCall.ForEach != nil:
-			forEach, diags := evaluateResourceForEachExpression(n.ModuleCall.ForEach, ctx)
+			forEach, diags := evaluateForEachExpression(n.ModuleCall.ForEach, ctx)
 			if diags.HasErrors() {
 				return nil, diags.Err()
 			}

terraform/node_resource_refresh.go

@@ -89,32 +89,34 @@ func (n *NodeRefreshableManagedResource) Path() addrs.ModuleInstance {
 func (n *NodeRefreshableManagedResource) DynamicExpand(ctx EvalContext) (*Graph, error) {
 	var diags tfdiags.Diagnostics
 
-	count, countDiags := evaluateResourceCountExpression(n.Config.Count, ctx)
+	expander := ctx.InstanceExpander()
+	// Inform our instance expander about our expansion results, and then use
+	// it to calculate the instance addresses we'll expand for.
+	switch {
+	case n.Config.Count != nil:
+		count, countDiags := evaluateCountExpression(n.Config.Count, ctx)
 		diags = diags.Append(countDiags)
 		if countDiags.HasErrors() {
 			return nil, diags.Err()
 		}
 
-	forEachMap, forEachDiags := evaluateResourceForEachExpression(n.Config.ForEach, ctx)
+		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, count)
+
+	case n.Config.ForEach != nil:
+		forEachMap, forEachDiags := evaluateForEachExpression(n.Config.ForEach, ctx)
 		if forEachDiags.HasErrors() {
 			return nil, diags.Err()
 		}
 
-	// Next we need to potentially rename an instance address in the state
-	// if we're transitioning whether "count" is set at all.
-	fixResourceCountSetTransition(ctx, n.Addr.Config(), count != -1)
-
-	// Inform our instance expander about our expansion results above,
-	// and then use it to calculate the instance addresses we'll expand for.
-	expander := ctx.InstanceExpander()
-	switch {
-	case count >= 0:
-		expander.SetResourceCount(n.Addr.Module, n.Addr.Resource, count)
-	case forEachMap != nil:
 		expander.SetResourceForEach(n.Addr.Module, n.Addr.Resource, forEachMap)
+
 	default:
 		expander.SetResourceSingle(n.Addr.Module, n.Addr.Resource)
 	}
+
+	// Next we need to potentially rename an instance address in the state
+	// if we're transitioning whether "count" is set at all.
+	fixResourceCountSetTransition(ctx, n.Addr.Config(), n.Config.Count != nil)
 	instanceAddrs := expander.ExpandResource(n.Addr)
 
 	// Our graph transformers require access to the full state, so we'll