feat(analyzer): allOf is honored wherever it appears, not only on named schemas

internal/analyzer/schemas.go

@@ -629,6 +629,21 @@ func (a *Analyzer) resolveGoType(schema *highbase.Schema, nameHint string) strin
 		return name
 	}
 
+	// An allOf composes other schemas. A lone $ref inside one is how a 3.0 spec
+	// hangs a description or nullable on a reference, since keywords beside a
+	// $ref are ignored, and it means the type it references. Anything else
+	// composes a shape of its own and is named like any other inline schema.
+	if len(schema.AllOf) > 0 {
+		if len(schema.AllOf) == 1 {
+			if goType := a.goTypeForRef(schema.AllOf[0].GetReference()); goType != "" {
+				return goType
+			}
+		}
+		if name, ok := a.synthesizeInlineAllOf(schema, nameHint); ok {
+			return name
+		}
+	}
+
 	// Enum type referenced inline -- use the primary type.
 	primaryType := primaryType(schema)
 
@@ -769,6 +784,56 @@ func (a *Analyzer) synthesizeInlineObject(schema *highbase.Schema, nameHint stri
 	return goName, true
 }
 
+// synthesizeInlineAllOf declares a named struct for a composition written inline,
+// so what it composes stays typed instead of collapsing into any.
+func (a *Analyzer) synthesizeInlineAllOf(schema *highbase.Schema, nameHint string) (string, bool) {
+	// Multipart is a property of where the schema is used, and a body composed
+	// through allOf is used the same way one written as an object is: its binary
+	// properties are file parts, not base64 text.
+	multipartBody := a.inlineMultipartBodies[nameHint]
+
+	if schema.Title != "" {
+		nameHint = schema.Title
+	}
+	if nameHint == "" {
+		return "", false
+	}
+
+	key := a.inlineAllOfKey(schema, nameHint)
+	if existing, ok := a.synthesizedByKey[key]; ok {
+		return existing.Name, true
+	}
+
+	goName := a.namer.Unique(naming.Exported(nameHint))
+	td, err := a.convertAllOf(goName, schema, false, multipartBody)
+	if err != nil || td == nil {
+		return "", false
+	}
+	a.synthesizedByKey[key] = td
+	a.synthesized = append(a.synthesized, td)
+	return goName, true
+}
+
+// inlineAllOfKey identifies a composition by what it composes, so the same one
+// written twice lands on one type.
+func (a *Analyzer) inlineAllOfKey(schema *highbase.Schema, nameHint string) string {
+	var b strings.Builder
+	b.WriteString("allOf")
+	for i, proxy := range schema.AllOf {
+		if ref := proxy.GetReference(); ref != "" {
+			b.WriteString("|" + ref)
+			continue
+		}
+		entry, err := proxy.BuildSchema()
+		if err != nil || entry == nil {
+			b.WriteString("|?")
+			continue
+		}
+		b.WriteString("|" + a.inlineObjectKey(entry, nameHint+"Part"+strconv.Itoa(i)))
+	}
+	return b.String()
+}
+
 // inlineObjectKey identifies an inline object by the Go it would generate, so two
 // properties declaring the same shape land on one type rather than two names for
 // it.

internal/analyzer/schemas_allof_property_test.go

@@ -0,0 +1,193 @@
+package analyzer
+
+import "testing"
+
+const allOfPropertySpec = `openapi: 3.1.0
+info: { title: t, version: "1" }
+paths: {}
+components:
+  schemas:
+    View:
+      type: object
+      properties:
+        creator:
+          allOf:
+            - $ref: "#/components/schemas/User"
+        author:
+          readOnly: true
+          description: The author.
+          allOf:
+            - $ref: "#/components/schemas/User"
+        same:
+          allOf:
+            - $ref: "#/components/schemas/User"
+        composed:
+          description: A user with a role beside it.
+          allOf:
+            - $ref: "#/components/schemas/User"
+            - type: object
+              properties:
+                role: { type: string }
+        inline:
+          allOf:
+            - type: object
+              properties:
+                only: { type: string }
+    User:
+      type: object
+      properties:
+        login: { type: string }
+      required: [login]
+`
+
+// allOf is JSON Schema composition, and a lone $ref inside one says the value
+// must match that schema, which is to say it is of that type.
+func TestAllOfProperty_LoneRefResolvesToIt(t *testing.T) {
+	_, typeMap := analyzeSpec(t, allOfPropertySpec)
+
+	view := typeMap["View"]
+	if view == nil {
+		t.Fatal("View not found")
+	}
+	byJSON := map[string]string{}
+	for _, f := range view.Fields {
+		byJSON[f.JSONName] = f.Type
+	}
+
+	if byJSON["creator"] != "*User" {
+		t.Errorf("creator = %q, want *User", byJSON["creator"])
+	}
+	// Keywords beside the allOf are handled where they belong, so the
+	// composition still resolves to what it composes.
+	if byJSON["author"] != "*User" {
+		t.Errorf("author = %q, want *User", byJSON["author"])
+	}
+	if byJSON["same"] != "*User" {
+		t.Errorf("same = %q, want *User", byJSON["same"])
+	}
+}
+
+// A composition of more than a reference is a shape of its own, and gets a name
+// like any other inline schema.
+func TestAllOfProperty_CompositionIsNamed(t *testing.T) {
+	_, typeMap := analyzeSpec(t, allOfPropertySpec)
+
+	view := typeMap["View"]
+	byJSON := map[string]string{}
+	for _, f := range view.Fields {
+		byJSON[f.JSONName] = f.Type
+	}
+
+	if byJSON["composed"] != "*ViewComposed" {
+		t.Fatalf("composed = %q, want *ViewComposed", byJSON["composed"])
+	}
+	composed := typeMap["ViewComposed"]
+	if composed == nil {
+		t.Fatal("ViewComposed not synthesized")
+	}
+	if len(composed.Fields) != 2 {
+		t.Fatalf("ViewComposed fields = %+v, want the embed and the property", composed.Fields)
+	}
+	if !composed.Fields[0].Embedded || composed.Fields[0].Type != "User" {
+		t.Errorf("ViewComposed field 0 = %+v, want an embedded User", composed.Fields[0])
+	}
+	if composed.Fields[1].JSONName != "role" {
+		t.Errorf("ViewComposed field 1 = %+v, want role", composed.Fields[1])
+	}
+
+	// A single inline entry composes just as much as several do.
+	if byJSON["inline"] != "*ViewInline" {
+		t.Errorf("inline = %q, want *ViewInline", byJSON["inline"])
+	}
+}
+
+const refIdiomSpec = `openapi: 3.1.0
+info: { title: t, version: "1" }
+paths: {}
+components:
+  schemas:
+    Advisory:
+      type: object
+      properties:
+        siblings:
+          $ref: "#/components/schemas/User"
+          description: 3.1 allows keywords beside a reference.
+          readOnly: true
+        nullableRef:
+          anyOf:
+            - $ref: "#/components/schemas/User"
+            - type: "null"
+    User:
+      type: object
+      properties: { login: { type: string } }
+      required: [login]
+`
+
+// The ways 3.1 says the same things without allOf: keywords beside a $ref, and a
+// null member for a nullable one. Both resolve to the referenced type, and this
+// keeps them that way.
+func TestRefIdioms_3_1(t *testing.T) {
+	_, typeMap := analyzeSpec(t, refIdiomSpec)
+
+	byJSON := map[string]string{}
+	for _, f := range typeMap["Advisory"].Fields {
+		byJSON[f.JSONName] = f.Type
+	}
+	if byJSON["siblings"] != "*User" {
+		t.Errorf("a $ref with sibling keywords = %q, want *User", byJSON["siblings"])
+	}
+	if byJSON["nullableRef"] != "*User" {
+		t.Errorf("anyOf with a null member = %q, want *User", byJSON["nullableRef"])
+	}
+}
+
+const allOfMultipartSpec = `openapi: 3.1.0
+info: { title: t, version: "1" }
+paths:
+  /upload:
+    post:
+      operationId: upload
+      requestBody:
+        required: true
+        content:
+          multipart/form-data:
+            schema:
+              allOf:
+                - $ref: "#/components/schemas/Meta"
+                - type: object
+                  properties:
+                    file: { type: string, format: binary }
+                  required: [file]
+      responses:
+        "204": { description: ok }
+components:
+  schemas:
+    Meta:
+      type: object
+      properties:
+        label: { type: string }
+      required: [label]
+`
+
+// Multipart is a property of where a schema is used, and a body composed through
+// allOf is used the same way one written as an object is: its binary properties
+// are file parts rather than base64 text in an ordinary field.
+func TestAllOfProperty_MultipartBodyKeepsItsFileParts(t *testing.T) {
+	_, typeMap := analyzeSpec(t, allOfMultipartSpec)
+
+	body := typeMap["UploadBody"]
+	if body == nil {
+		t.Fatal("UploadBody not found")
+	}
+	byJSON := map[string]string{}
+	for _, f := range body.Fields {
+		byJSON[f.JSONName] = f.Type
+	}
+	if byJSON["file"] != "FormFile" {
+		t.Errorf("file = %q, want FormFile", byJSON["file"])
+	}
+	// What it composes comes along.
+	if len(body.Fields) != 2 || !body.Fields[0].Embedded || body.Fields[0].Type != "Meta" {
+		t.Errorf("fields = %+v, want the embedded Meta beside the file", body.Fields)
+	}
+}

internal/generator/e2e_allof_property_test.go

@@ -0,0 +1,98 @@
+package generator
+
+import "testing"
+
+const allOfPropertyAPISpec = `openapi: 3.1.0
+info: { title: advisories, version: "1" }
+paths:
+  /advisories/{id}:
+    get:
+      operationId: getAdvisory
+      parameters:
+        - { name: id, in: path, required: true, schema: { type: string } }
+      responses:
+        "200":
+          description: ok
+          content:
+            application/json: { schema: { $ref: "#/components/schemas/Advisory" } }
+components:
+  schemas:
+    Advisory:
+      type: object
+      properties:
+        id: { type: string }
+        author:
+          description: The author of the advisory.
+          allOf:
+            - $ref: "#/components/schemas/User"
+            - type: "null"
+        reviewer:
+          description: Who reviewed it, with their verdict.
+          allOf:
+            - $ref: "#/components/schemas/User"
+            - type: object
+              properties:
+                verdict: { type: string }
+      required: [id]
+    User:
+      type: object
+      properties:
+        login: { type: string }
+      required: [login]
+`
+
+// TestE2E_AllOfPropertiesAreTyped covers allOf where a property is typed. The
+// analyzer composed it for a named schema and not for an inline one, so a
+// property resolved to any and a caller had to assert their way into a schema
+// the spec names.
+func TestE2E_AllOfPropertiesAreTyped(t *testing.T) {
+	files, _ := generateFromSpec(t, allOfPropertyAPISpec, "advapi")
+
+	runGeneratedWireTest(t, files, "allofproperty", `package advapi
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestWrappedRefDecodesAsItsType(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`+"`"+`{"id":"a-1","author":{"login":"ada"},"reviewer":{"login":"bo","verdict":"ok"}}`+"`"+`))
+	}))
+	defer srv.Close()
+
+	adv, err := NewClient(srv.URL).GetAdvisory(t.Context(), "a-1")
+	if err != nil {
+		t.Fatalf("GetAdvisory: %v", err)
+	}
+
+	// A plain read rather than an assertion into map[string]any.
+	if adv.Author == nil || adv.Author.Login != "ada" {
+		t.Errorf("author = %+v, want the referenced User", adv.Author)
+	}
+
+	// A composition keeps both halves: what it references and what it adds.
+	if adv.Reviewer == nil || adv.Reviewer.Login != "bo" {
+		t.Errorf("reviewer = %+v, want the embedded User", adv.Reviewer)
+	}
+	if adv.Reviewer.Verdict == nil || *adv.Reviewer.Verdict != "ok" {
+		t.Errorf("verdict = %v, want ok", adv.Reviewer.Verdict)
+	}
+}
+
+// The pointer carries absence, so a null author stays distinguishable from one
+// that is present and empty.
+func TestNullWrappedRefIsNil(t *testing.T) {
+	var adv Advisory
+	if err := json.Unmarshal([]byte(`+"`"+`{"id":"a-2","author":null}`+"`"+`), &adv); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if adv.Author != nil {
+		t.Errorf("author = %+v, want nil", adv.Author)
+	}
+}
+`)
+}