Reflect v0.15 schema changes (#28)

* Reflect v0.15 schema changes

* Bump format version

schemas.go

@@ -10,7 +10,7 @@ import (
 
 // ProviderSchemasFormatVersion is the version of the JSON provider
 // schema format that is supported by this package.
-const ProviderSchemasFormatVersion = "0.1"
+const ProviderSchemasFormatVersion = "0.2"
 
 // ProviderSchemas represents the schemas of all providers and
 // resources in use by the configuration.
@@ -38,8 +38,10 @@ func (p *ProviderSchemas) Validate() error {
 		return errors.New("unexpected provider schema data, format version is missing")
 	}
 
-	if ProviderSchemasFormatVersion != p.FormatVersion {
-		return fmt.Errorf("unsupported provider schema data format version: expected %q, got %q", PlanFormatVersion, p.FormatVersion)
+	oldVersion := "0.1"
+	if p.FormatVersion != ProviderSchemasFormatVersion && p.FormatVersion != oldVersion {
+		return fmt.Errorf("unsupported provider schema data format version: expected %q or %q, got %q",
+			PlanFormatVersion, oldVersion, p.FormatVersion)
 	}
 
 	return nil
@@ -123,6 +125,20 @@ const (
 	// with a single-element constraint.
 	SchemaNestingModeSingle SchemaNestingMode = "single"
 
+	// SchemaNestingModeGroup is similar to SchemaNestingModeSingle in that it
+	// calls for only a single instance of a given block type with no labels,
+	// but it additonally guarantees that its result will never be null,
+	// even if the block is absent, and instead the nested attributes
+	// and blocks will be treated as absent in that case.
+	//
+	// This is useful for the situation where a remote API has a feature that
+	// is always enabled but has a group of settings related to that feature
+	// that themselves have default values. By using SchemaNestingModeGroup
+	// instead of SchemaNestingModeSingle in that case, generated plans will
+	// show the block as present even when not present in configuration,
+	// thus allowing any default values within to be displayed to the user.
+	SchemaNestingModeGroup SchemaNestingMode = "group"
+
 	// SchemaNestingModeList denotes list block nesting mode, which
 	// allows an ordered list of blocks where duplicates are allowed.
 	SchemaNestingModeList SchemaNestingMode = "list"
@@ -162,9 +178,14 @@ type SchemaBlockType struct {
 
 // SchemaAttribute describes an attribute within a schema block.
 type SchemaAttribute struct {
-	// The attribute type.
+	// The attribute type
+	// Either AttributeType or AttributeNestedType is set, never both.
 	AttributeType cty.Type `json:"type,omitempty"`
 
+	// Details about a nested attribute type
+	// Either AttributeType or AttributeNestedType is set, never both.
+	AttributeNestedType *SchemaNestedAttributeType `json:"nested_type,omitempty"`
+
 	// The description field for this attribute. If no kind is
 	// provided, it can be assumed to be plain text.
 	Description     string                `json:"description,omitempty"`
@@ -191,3 +212,23 @@ type SchemaAttribute struct {
 	// treat these values with greater care than non-sensitive fields.
 	Sensitive bool `json:"sensitive,omitempty"`
 }
+
+// SchemaNestedAttributeType describes a nested attribute
+// which could also be just expressed simply as cty.Object(...),
+// cty.List(cty.Object(...)) etc. but this allows tracking additional
+// metadata which can help interpreting or validating the data.
+type SchemaNestedAttributeType struct {
+	// A map of nested attributes
+	Attributes map[string]*SchemaAttribute `json:"attributes,omitempty"`
+
+	// The nesting mode for this attribute.
+	NestingMode string `json:"nesting_mode,omitempty"`
+
+	// The lower limit on number of items that can be declared
+	// of this attribute type.
+	MinItems uint64 `json:"min_items,omitempty"`
+
+	// The upper limit on number of items that can be declared
+	// of this attribute type.
+	MaxItems uint64 `json:"max_items,omitempty"`
+}