Refactor shim interfaces to not be implementable externally (#3100)

This PR is a pure refactor. The `shim` interfaces are not intended to be
implemented externally. They change often and due to the fact they are
public we have kept accruing new variants to keep the public interface
backwards compatible which add unnecessary complexity.

This PR adds `InternalInterface` interface with a private method which
is only implemented by `internalinter.Internal`. This can be embedded in
interfaces which are not intended to be implemented outside of the
bridge. Implementers in the bridge can embed the implementation of
`InternalInterface` but external users can not.

This means that we are free to add methods to interfaces which are not
intended to be implemented externally. This will in turn allow us to
delete some of the `Schema` and `Resource` variants under `shim`.

Author: VenelinMartinov

pkg/internal/internalinter/internalinter.go

@@ -0,0 +1,9 @@
+package internalinter
+
+type InternalInterface interface {
+	noimplement()
+}
+
+type Internal struct{}
+
+func (s Internal) noimplement() {}

pkg/pf/internal/schemashim/attr_schema.go

@@ -18,6 +18,7 @@ import (
 	pfattr "github.com/hashicorp/terraform-plugin-framework/attr"
 	"github.com/hashicorp/terraform-plugin-framework/types/basetypes"
 
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/pfutils"
 	bridge "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfbridge"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
@@ -26,6 +27,11 @@ import (
 type attrSchema struct {
 	key  string
 	attr pfutils.Attr
+	internalinter.Internal
+}
+
+func newAttrSchema(key string, attr pfutils.Attr) *attrSchema {
+	return &attrSchema{key, attr, internalinter.Internal{}}
 }
 
 var _ shim.Schema = (*attrSchema)(nil)

pkg/pf/internal/schemashim/block_schema.go

@@ -20,6 +20,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/attr"
 	"github.com/hashicorp/terraform-plugin-framework/types/basetypes"
 
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/pfutils"
 	bridge "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfbridge"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
@@ -28,10 +29,11 @@ import (
 type blockSchema struct {
 	key   string
 	block pfutils.Block
+	internalinter.Internal
 }
 
 func newBlockSchema(key string, block pfutils.Block) *blockSchema {
-	return &blockSchema{key, block}
+	return &blockSchema{key, block, internalinter.Internal{}}
 }
 
 var _ shim.Schema = (*blockSchema)(nil)

pkg/pf/internal/schemashim/custom_type_test.go

@@ -51,7 +51,7 @@ func TestCustomTypeEmbeddingObjectType(t *testing.T) {
 		},
 	}
 
-	shimmed := &blockSchema{"key", pfutils.FromBlockLike(raw)}
+	shimmed := newBlockSchema("key", pfutils.FromBlockLike(raw))
 	assert.Equal(t, shim.TypeMap, shimmed.Type())
 	assert.NotNil(t, shimmed.Elem())
 	_, isPseudoResource := shimmed.Elem().(shim.Resource)
@@ -80,7 +80,7 @@ func TestCustomListType(t *testing.T) {
 		},
 	}
 
-	shimmed := &blockSchema{"key", pfutils.FromBlockLike(raw)}
+	shimmed := newBlockSchema("key", pfutils.FromBlockLike(raw))
 	assert.Equal(t, shim.TypeList, shimmed.Type())
 	assert.NotNil(t, shimmed.Elem())
 	_, isPseudoResource := shimmed.Elem().(shim.Resource)
@@ -109,7 +109,7 @@ func TestCustomListAttribute(t *testing.T) {
 		},
 	}
 
-	shimmed := &attrSchema{"key", pfutils.FromAttrLike(raw)}
+	shimmed := newAttrSchema("key", pfutils.FromAttrLike(raw))
 	assert.Equal(t, shim.TypeList, shimmed.Type())
 	assert.NotNil(t, shimmed.Elem())
 	_, isPseudoResource := shimmed.Elem().(shim.Schema)
@@ -138,7 +138,7 @@ func TestCustomSetType(t *testing.T) {
 		},
 	}
 
-	shimmed := &blockSchema{"key", pfutils.FromBlockLike(raw)}
+	shimmed := newBlockSchema("key", pfutils.FromBlockLike(raw))
 	assert.Equal(t, shim.TypeSet, shimmed.Type())
 	assert.NotNil(t, shimmed.Elem())
 	_, isPseudoResource := shimmed.Elem().(shim.Resource)

pkg/pf/internal/schemashim/datasource.go

@@ -15,12 +15,14 @@
 package schemashim
 
 import (
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/runtypes"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
 )
 
 type schemaOnlyDataSource struct {
 	tf runtypes.Schema
+	internalinter.Internal
 }
 
 var _ shim.Resource = (*schemaOnlyDataSource)(nil)

pkg/pf/internal/schemashim/datasource_map.go

@@ -17,6 +17,7 @@ package schemashim
 import (
 	"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
 
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/runtypes"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
 )
@@ -27,7 +28,7 @@ func newSchemaOnlyDataSourceMap(dataSources runtypes.DataSources) schemaOnlyData
 	for _, name := range dataSources.All() {
 		key := string(name)
 		v := dataSources.Schema(name)
-		m[key] = &schemaOnlyDataSource{v}
+		m[key] = &schemaOnlyDataSource{v, internalinter.Internal{}}
 	}
 	return m
 }

pkg/pf/internal/schemashim/object_pseudoresource.go

@@ -25,6 +25,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-go/tftypes"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
 
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/pfutils"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
 )
@@ -38,6 +39,7 @@ type objectPseudoResource struct {
 	nestedAttrs  map[string]pfutils.Attr
 	nestedBlocks map[string]pfutils.Block // should have disjoint keys from nestedAttrs
 	allAttrNames []string
+	internalinter.Internal
 }
 
 func newObjectPseudoResource(t basetypes.ObjectTypable,
@@ -127,7 +129,7 @@ func (r *objectPseudoResource) GetOk(key string) (shim.Schema, bool) {
 	// and recurse using attrSchema. This information may be coming out of band from the ObjectTypeable value itself
 	// when using blocks, see TestCustomTypeEmbeddingObjectType.
 	if attr, ok := r.nestedAttrs[key]; ok {
-		return &attrSchema{key, attr}, true
+		return newAttrSchema(key, attr), true
 	}
 
 	// Nested blocks are similar to attributes:
@@ -169,6 +171,7 @@ type tuplePseudoResource struct {
 	schemaOnly
 	attrs map[string]pfutils.Attr
 	tuple attr.TypeWithElementTypes
+	internalinter.Internal
 }
 
 type tupElementAttr struct{ e attr.Type }

pkg/pf/internal/schemashim/object_type_test.go

@@ -37,7 +37,7 @@ func TestObjectAttribute(t *testing.T) {
 			"s": basetypes.StringType{},
 		},
 	}
-	shimmed := &attrSchema{"key", pfutils.FromAttrLike(objectAttr)}
+	shimmed := newAttrSchema("key", pfutils.FromAttrLike(objectAttr))
 	assertIsObjectType(t, shimmed)
 	s := shimmed.Elem().(shim.Resource).Schema().Get("s")
 	assert.Equal(t, shim.TypeString, s.Type())
@@ -57,7 +57,7 @@ func TestSingleNestedBlock(t *testing.T) {
 	b := schema.SingleNestedBlock{
 		Attributes: simpleObjectAttributes(),
 	}
-	shimmed := &blockSchema{"key", pfutils.FromResourceBlock(b)}
+	shimmed := newBlockSchema("key", pfutils.FromResourceBlock(b))
 	assertIsObjectType(t, shimmed)
 	assert.Equal(t, "obj[c=str,co=str,desc=str,o=str,r=str]", schemaLogicalType(shimmed).String())
 	r, ok := shimmed.Elem().(shim.Resource)
@@ -72,7 +72,7 @@ func TestListNestedBlock(t *testing.T) {
 			Attributes: simpleObjectAttributes(),
 		},
 	}
-	shimmed := &blockSchema{"key", pfutils.FromResourceBlock(b)}
+	shimmed := newBlockSchema("key", pfutils.FromResourceBlock(b))
 	assert.Equal(t, "list[obj[c=str,co=str,desc=str,o=str,r=str]]", schemaLogicalType(shimmed).String())
 	r, ok := shimmed.Elem().(shim.Resource)
 	require.True(t, ok, "List-nested TF blocks should be represented as Elem() shim.Resource")
@@ -86,7 +86,7 @@ func TestSetNestedBlock(t *testing.T) {
 			Attributes: simpleObjectAttributes(),
 		},
 	}
-	shimmed := &blockSchema{"key", pfutils.FromResourceBlock(b)}
+	shimmed := newBlockSchema("key", pfutils.FromResourceBlock(b))
 	assert.Equal(t, "set[obj[c=str,co=str,desc=str,o=str,r=str]]", schemaLogicalType(shimmed).String())
 	r, ok := shimmed.Elem().(shim.Resource)
 	require.True(t, ok, "Set-nested TF blocks should be represented as Elem() shim.Resource")

pkg/pf/internal/schemashim/provider.go

@@ -23,6 +23,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-go/tfprotov6"
 	"github.com/hashicorp/terraform-plugin-go/tftypes"
 
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/pfutils"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/runtypes"
@@ -36,6 +37,7 @@ type SchemaOnlyProvider struct {
 	tf            pfprovider.Provider
 	resourceMap   schemaOnlyResourceMap
 	dataSourceMap schemaOnlyDataSourceMap
+	internalinter.Internal
 }
 
 func (p *SchemaOnlyProvider) Server(ctx context.Context) (tfprotov6.ProviderServer, error) {

pkg/pf/internal/schemashim/resource.go

@@ -15,12 +15,18 @@
 package schemashim
 
 import (
+	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/internal/internalinter"
 	"github.com/pulumi/pulumi-terraform-bridge/v3/pkg/pf/internal/runtypes"
 	shim "github.com/pulumi/pulumi-terraform-bridge/v3/pkg/tfshim"
 )
 
 type schemaOnlyResource struct {
 	tf runtypes.Schema
+	internalinter.Internal
+}
+
+func newSchemaOnlyResource(tf runtypes.Schema) *schemaOnlyResource {
+	return &schemaOnlyResource{tf, internalinter.Internal{}}
 }
 
 var _ shim.Resource = (*schemaOnlyResource)(nil)