MinItems with dynamic blocks

builtin/providers/test/provider.go

@@ -37,6 +37,7 @@ func Provider() terraform.ResourceProvider {
 			"test_resource_config_mode":      testResourceConfigMode(),
 			"test_resource_nested_id":        testResourceNestedId(),
 			"test_undeleteable":              testResourceUndeleteable(),
+			"test_resource_required_min":     testResourceRequiredMin(),
 		},
 		DataSourcesMap: map[string]*schema.Resource{
 			"test_data_source":    testDataSource(),

builtin/providers/test/resource_required_min.go

@@ -0,0 +1,68 @@
+package test
+
+import (
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func testResourceRequiredMin() *schema.Resource {
+	return &schema.Resource{
+		Create: testResourceRequiredMinCreate,
+		Read:   testResourceRequiredMinRead,
+		Update: testResourceRequiredMinUpdate,
+		Delete: testResourceRequiredMinDelete,
+
+		CustomizeDiff: func(d *schema.ResourceDiff, _ interface{}) error {
+			if d.HasChange("dependent_list") {
+				d.SetNewComputed("computed_list")
+			}
+			return nil
+		},
+
+		Schema: map[string]*schema.Schema{
+			"min_items": {
+				Type:     schema.TypeList,
+				Optional: true,
+				MinItems: 2,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"val": {
+							Type:     schema.TypeString,
+							Required: true,
+						},
+					},
+				},
+			},
+			"required_min_items": {
+				Type:     schema.TypeList,
+				Required: true,
+				MinItems: 2,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"val": {
+							Type:     schema.TypeString,
+							Required: true,
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func testResourceRequiredMinCreate(d *schema.ResourceData, meta interface{}) error {
+	d.SetId("testId")
+	return testResourceRequiredMinRead(d, meta)
+}
+
+func testResourceRequiredMinRead(d *schema.ResourceData, meta interface{}) error {
+	return nil
+}
+
+func testResourceRequiredMinUpdate(d *schema.ResourceData, meta interface{}) error {
+	return testResourceRequiredMinRead(d, meta)
+}
+
+func testResourceRequiredMinDelete(d *schema.ResourceData, meta interface{}) error {
+	d.SetId("")
+	return nil
+}

builtin/providers/test/resource_required_min_test.go

@@ -0,0 +1,66 @@
+package test
+
+import (
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestResource_dynamicRequiredMinItems(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckResourceDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: `
+resource "test_resource_required_min" "a" {
+}
+`,
+				ExpectError: regexp.MustCompile(`"required_min_items" blocks are required`),
+			},
+			resource.TestStep{
+				Config: strings.TrimSpace(`
+resource "test_resource_list" "a" {
+	dependent_list {
+		val = "a"
+	}
+}
+
+resource "test_resource_required_min" "b" {
+	dynamic "required_min_items" {
+		for_each = test_resource_list.a.computed_list
+		content {
+		  val = required_min_items.value
+		}
+	}
+}
+				`),
+				ExpectError: regexp.MustCompile(`required_min_items: attribute supports 2 item as a minimum`),
+			},
+			resource.TestStep{
+				Config: strings.TrimSpace(`
+resource "test_resource_list" "c" {
+	dependent_list {
+		val = "a"
+	}
+
+	dependent_list {
+		val = "b"
+	}
+}
+
+resource "test_resource_required_min" "b" {
+	dynamic "required_min_items" {
+		for_each = test_resource_list.c.computed_list
+		content {
+		  val = required_min_items.value
+		}
+	}
+}
+				`),
+			},
+		},
+	})
+}

configs/configschema/coerce_value.go

@@ -113,7 +113,10 @@ func (b *Block) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) {
 					return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a list")
 				}
 				l := coll.LengthInt()
-				if l < blockS.MinItems {
+
+				// Assume that if there are unknowns this could have come from
+				// a dynamic block, and we can't validate MinItems yet.
+				if l < blockS.MinItems && coll.IsWhollyKnown() {
 					return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems)
 				}
 				if l > blockS.MaxItems && blockS.MaxItems > 0 {
@@ -161,7 +164,10 @@ func (b *Block) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) {
 					return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a set")
 				}
 				l := coll.LengthInt()
-				if l < blockS.MinItems {
+
+				// Assume that if there are unknowns this could have come from
+				// a dynamic block, and we can't validate MinItems yet.
+				if l < blockS.MinItems && coll.IsWhollyKnown() {
 					return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems)
 				}
 				if l > blockS.MaxItems && blockS.MaxItems > 0 {

configs/configschema/coerce_value_test.go

@@ -331,7 +331,7 @@ func TestCoerceValue(t *testing.T) {
 					"foo": {
 						Block:    Block{},
 						Nesting:  NestingList,
-						MinItems: 1,
+						MinItems: 2,
 					},
 				},
 			},
@@ -345,6 +345,39 @@ func TestCoerceValue(t *testing.T) {
 			}),
 			"",
 		},
+		"unknowns in nested list": {
+			&Block{
+				BlockTypes: map[string]*NestedBlock{
+					"foo": {
+						Block: Block{
+							Attributes: map[string]*Attribute{
+								"attr": {
+									Type:     cty.String,
+									Required: true,
+								},
+							},
+						},
+						Nesting:  NestingList,
+						MinItems: 2,
+					},
+				},
+			},
+			cty.ObjectVal(map[string]cty.Value{
+				"foo": cty.ListVal([]cty.Value{
+					cty.ObjectVal(map[string]cty.Value{
+						"attr": cty.UnknownVal(cty.String),
+					}),
+				}),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"foo": cty.ListVal([]cty.Value{
+					cty.ObjectVal(map[string]cty.Value{
+						"attr": cty.UnknownVal(cty.String),
+					}),
+				}),
+			}),
+			"",
+		},
 		"unknown nested set": {
 			&Block{
 				Attributes: map[string]*Attribute{

configs/configschema/decoder_spec.go

@@ -33,6 +33,14 @@ func (b *Block) DecoderSpec() hcldec.Spec {
 
 		childSpec := blockS.Block.DecoderSpec()
 
+		// We can only validate 0 or 1 for MinItems, because a dynamic block
+		// may satisfy any number of min items while only having a single
+		// block in the config.
+		minItems := 0
+		if blockS.MinItems > 1 {
+			minItems = 1
+		}
+
 		switch blockS.Nesting {
 		case NestingSingle, NestingGroup:
 			ret[name] = &hcldec.BlockSpec{
@@ -57,14 +65,14 @@ func (b *Block) DecoderSpec() hcldec.Spec {
 				ret[name] = &hcldec.BlockTupleSpec{
 					TypeName: name,
 					Nested:   childSpec,
-					MinItems: blockS.MinItems,
+					MinItems: minItems,
 					MaxItems: blockS.MaxItems,
 				}
 			} else {
 				ret[name] = &hcldec.BlockListSpec{
 					TypeName: name,
 					Nested:   childSpec,
-					MinItems: blockS.MinItems,
+					MinItems: minItems,
 					MaxItems: blockS.MaxItems,
 				}
 			}
@@ -77,7 +85,7 @@ func (b *Block) DecoderSpec() hcldec.Spec {
 			ret[name] = &hcldec.BlockSetSpec{
 				TypeName: name,
 				Nested:   childSpec,
-				MinItems: blockS.MinItems,
+				MinItems: minItems,
 				MaxItems: blockS.MaxItems,
 			}
 		case NestingMap:

configs/configschema/decoder_spec_test.go

@@ -356,6 +356,33 @@ func TestBlockDecoderSpec(t *testing.T) {
 			}),
 			1, // too many "foo" blocks
 		},
+		// dynamic blocks may fulfill MinItems, but there is only one block to
+		// decode.
+		"required MinItems": {
+			&Block{
+				BlockTypes: map[string]*NestedBlock{
+					"foo": {
+						Nesting:  NestingList,
+						Block:    Block{},
+						MinItems: 2,
+					},
+				},
+			},
+			hcltest.MockBody(&hcl.BodyContent{
+				Blocks: hcl.Blocks{
+					&hcl.Block{
+						Type: "foo",
+						Body: hcl.EmptyBody(),
+					},
+				},
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"foo": cty.ListVal([]cty.Value{
+					cty.EmptyObjectVal,
+				}),
+			}),
+			0,
+		},
 		"extraneous attribute": {
 			&Block{},
 			hcltest.MockBody(&hcl.BodyContent{

helper/schema/schema.go

@@ -1456,6 +1456,15 @@ func (m schemaMap) validateList(
 			"%s: should be a list", k)}
 	}
 
+	// We can't validate list length if this came from a dynamic block.
+	// Since there's no way to determine if something was from a dynamic block
+	// at this point, we're going to skip validation in the new protocol if
+	// there are any unknowns. Validate will eventually be called again once
+	// all values are known.
+	if isProto5() && !isWhollyKnown(raw) {
+		return nil, nil
+	}
+
 	// Validate length
 	if schema.MaxItems > 0 && rawV.Len() > schema.MaxItems {
 		return nil, []error{fmt.Errorf(