fix(graphql): define @interfaceObject and @composeDirective in federation prelude

internal/graphql/lint/federation.go

@@ -25,11 +25,10 @@
 // Directive signatures below come from the Apollo Federation subgraph
 // specification (github.com/apollographql/federation,
 // docs/source/schema-design/federated-schemas/reference/subgraph-spec.mdx,
-// fetched 2026-08-21). Only the 9 directives named in
+// fetched 2026-10-22). Only the directives named in
 // federationDirectives are supported; an import naming any other
-// directive, for example @interfaceObject or @authenticated added in
-// later spec versions, is reported by name instead of assuming an
-// unverified signature.
+// directive, for example @authenticated added in later spec versions,
+// is reported by name instead of assuming an unverified signature.
 
 package lint
 
@@ -91,15 +90,17 @@ type federationDirective struct {
 //
 //nolint:gochecknoglobals,lll // Why: a fixed lookup table, never mutated; Go has no map consts, and directive location lists can't be wrapped.
 var federationDirectives = map[string]federationDirective{
-	"key":          {sdl: "directive @%[1]s(fields: FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE", needsFieldSet: true},
-	"shareable":    {sdl: "directive @%[1]s repeatable on OBJECT | FIELD_DEFINITION"},
-	"override":     {sdl: "directive @%[1]s(from: String!) on FIELD_DEFINITION"},
-	"inaccessible": {sdl: "directive @%[1]s on FIELD_DEFINITION | OBJECT | INTERFACE | UNION | ARGUMENT_DEFINITION | SCALAR | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION"},
-	"external":     {sdl: "directive @%[1]s on FIELD_DEFINITION | OBJECT"},
-	"requires":     {sdl: "directive @%[1]s(fields: FieldSet!) on FIELD_DEFINITION", needsFieldSet: true},
-	"provides":     {sdl: "directive @%[1]s(fields: FieldSet!) on FIELD_DEFINITION", needsFieldSet: true},
-	"tag":          {sdl: "directive @%[1]s(name: String!) repeatable on FIELD_DEFINITION | INTERFACE | OBJECT | UNION | ARGUMENT_DEFINITION | SCALAR | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION"},
-	"extends":      {sdl: "directive @%[1]s on OBJECT | INTERFACE"},
+	"key":              {sdl: "directive @%[1]s(fields: FieldSet!, resolvable: Boolean = true) repeatable on OBJECT | INTERFACE", needsFieldSet: true},
+	"shareable":        {sdl: "directive @%[1]s repeatable on OBJECT | FIELD_DEFINITION"},
+	"override":         {sdl: "directive @%[1]s(from: String!) on FIELD_DEFINITION"},
+	"inaccessible":     {sdl: "directive @%[1]s on FIELD_DEFINITION | OBJECT | INTERFACE | UNION | ARGUMENT_DEFINITION | SCALAR | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION"},
+	"external":         {sdl: "directive @%[1]s on FIELD_DEFINITION | OBJECT"},
+	"requires":         {sdl: "directive @%[1]s(fields: FieldSet!) on FIELD_DEFINITION", needsFieldSet: true},
+	"provides":         {sdl: "directive @%[1]s(fields: FieldSet!) on FIELD_DEFINITION", needsFieldSet: true},
+	"tag":              {sdl: "directive @%[1]s(name: String!) repeatable on FIELD_DEFINITION | INTERFACE | OBJECT | UNION | ARGUMENT_DEFINITION | SCALAR | ENUM | ENUM_VALUE | INPUT_OBJECT | INPUT_FIELD_DEFINITION"},
+	"extends":          {sdl: "directive @%[1]s on OBJECT | INTERFACE"},
+	"interfaceObject":  {sdl: "directive @%[1]s on OBJECT"},
+	"composeDirective": {sdl: "directive @%[1]s(name: String!) repeatable on SCHEMA"},
 }
 
 // federationImport is a single entry from a `@link` import list,

internal/graphql/lint/federation_test.go

@@ -34,6 +34,94 @@ func TestFilesFederationImportedDirectivesPass(t *testing.T) {
 	assert.Equal(t, len(violations), 0)
 }
 
+// TestFilesFederationInterfaceObjectAndComposeDirectivePass confirms
+// that @interfaceObject and @composeDirective are defined when
+// imported. @composeDirective is applied to the schema itself.
+func TestFilesFederationInterfaceObjectAndComposeDirectivePass(t *testing.T) {
+	dir := t.TempDir()
+	path := writeFile(t, dir, "schema.graphql", `
+		extend schema
+			@link(url: "https://specs.apollo.dev/federation/v2.3", import: ["@key", "@interfaceObject", "@composeDirective"])
+			@composeDirective(name: "@custom")
+
+		directive @custom on FIELD_DEFINITION
+
+		type Widget @key(fields: "id") @interfaceObject {
+			id: ID!
+			name: String @custom
+		}
+	`)
+
+	violations, err := Files([]string{path}, &config.Lint{Federation: "v2.3"})
+	assert.NilError(t, err)
+	assert.Equal(t, len(violations), 0)
+}
+
+// TestFilesFederationInterfaceObjectAndComposeDirectiveLocations
+// confirms @interfaceObject is limited to object types and
+// @composeDirective to the schema.
+func TestFilesFederationInterfaceObjectAndComposeDirectiveLocations(t *testing.T) {
+	cases := []struct {
+		name    string
+		sdl     string
+		wantErr string
+	}{
+		{
+			"interfaceObject on a field",
+			`type Widget { id: ID! @interfaceObject }`,
+			"Directive interfaceObject is not applicable on FIELD_DEFINITION.",
+		},
+		{
+			"composeDirective on a type",
+			`type Widget @composeDirective(name: "@custom") { id: ID! }`,
+			"Directive composeDirective is not applicable on OBJECT.",
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			dir := t.TempDir()
+			path := writeFile(t, dir, "schema.graphql", `
+				extend schema @link(url: "https://specs.apollo.dev/federation/v2.3", import: ["@interfaceObject", "@composeDirective"])
+
+				`+c.sdl)
+
+			violations, err := Files([]string{path}, &config.Lint{Federation: "v2.3"})
+			assert.NilError(t, err)
+			assert.Equal(t, len(violations), 1)
+			assert.ErrorContains(t, violations[0].err, c.wantErr)
+		})
+	}
+}
+
+// TestFilesFederationInterfaceObjectAndComposeDirectiveHonorAs confirms
+// both directives can be imported under an alias, and that
+// @composeDirective is repeatable on the schema.
+func TestFilesFederationInterfaceObjectAndComposeDirectiveHonorAs(t *testing.T) {
+	dir := t.TempDir()
+	path := writeFile(t, dir, "schema.graphql", `
+		extend schema
+			@link(
+				url: "https://specs.apollo.dev/federation/v2.3"
+				import: [{name: "@composeDirective", as: "@compose"}, {name: "@interfaceObject", as: "@iface"}]
+			)
+			@compose(name: "@a")
+			@compose(name: "@b")
+
+		directive @a on FIELD_DEFINITION
+		directive @b on FIELD_DEFINITION
+
+		type Widget @iface {
+			id: ID!
+			name: String @a
+			label: String @b
+		}
+	`)
+
+	violations, err := Files([]string{path}, &config.Lint{Federation: "v2.3"})
+	assert.NilError(t, err)
+	assert.Equal(t, len(violations), 0)
+}
+
 // TestFilesFederationDirectiveNotImportedFails confirms the real
 // point of import-list awareness: a directive that exists in the
 // Federation spec but was never imported by this schema's own @link