Add support for Schema.Enums in HttpApiBuilder.isSingleStringType, closes #4471 (#4472)

Author: gcanti

.changeset/cold-lizards-cough.md

@@ -0,0 +1,41 @@
+---
+"effect": patch
+---
+
+Fix `Schema.Enums` `toString()` method to display correct enum values.
+
+Now, `toString()` correctly displays the actual enum values instead of internal numeric indices.
+
+**Before**
+
+```ts
+import { Schema } from "effect"
+
+enum Fruits {
+  Apple = "apple",
+  Banana = "banana",
+  Cantaloupe = 0
+}
+
+const schema = Schema.Enums(Fruits)
+
+console.log(String(schema))
+// Output: <enum 3 value(s): 0 | 1 | 2> ❌ (incorrect)
+```
+
+**After**
+
+```ts
+import { Schema } from "effect"
+
+enum Fruits {
+  Apple = "apple",
+  Banana = "banana",
+  Cantaloupe = 0
+}
+
+const schema = Schema.Enums(Fruits)
+
+console.log(String(schema))
+// Output: <enum 3 value(s): "apple" | "banana" | 0> ✅ (correct)
+```

.changeset/tiny-otters-wave.md

@@ -0,0 +1,5 @@
+---
+"@effect/platform": patch
+---
+
+Add support for `Schema.Enums` in `HttpApiBuilder.isSingleStringType`, closes #4471.

packages/effect/src/SchemaAST.ts

@@ -1067,7 +1067,7 @@ export class Enums implements Annotated {
   toString() {
     return Option.getOrElse(
       getExpected(this),
-      () => `<enum ${this.enums.length} value(s): ${this.enums.map((_, value) => JSON.stringify(value)).join(" | ")}>`
+      () => `<enum ${this.enums.length} value(s): ${this.enums.map(([_, value]) => JSON.stringify(value)).join(" | ")}>`
     )
   }
   /**

packages/effect/test/Schema/Schema/Enums/Enums.test.ts

@@ -58,7 +58,7 @@ describe("Enums", () => {
       await Util.assertions.decoding.fail(
         schema,
         "Cantaloupe",
-        `Expected <enum 3 value(s): 0 | 1 | 2>, actual "Cantaloupe"`
+        `Expected <enum 3 value(s): "apple" | "banana" | 0>, actual "Cantaloupe"`
       )
     })
 
@@ -85,7 +85,7 @@ describe("Enums", () => {
       await Util.assertions.decoding.fail(
         schema,
         "Cantaloupe",
-        `Expected <enum 3 value(s): 0 | 1 | 2>, actual "Cantaloupe"`
+        `Expected <enum 3 value(s): "apple" | "banana" | 3>, actual "Cantaloupe"`
       )
     })
 

packages/platform/src/HttpApiBuilder.ts

@@ -569,6 +569,7 @@ function isSingleStringType(ast: AST.AST, key?: PropertyKey): boolean {
     case "StringKeyword":
     case "Literal":
     case "TemplateLiteral":
+    case "Enums":
       return true
     case "TypeLiteral": {
       if (key !== undefined) {

packages/platform/test/HttpApiBuilder.test.ts

@@ -15,6 +15,29 @@ const assertNormalizedUrlParams = <UrlParams extends Schema.Schema.Any>(
 describe("HttpApiBuilder", () => {
   describe("normalizeUrlParams", () => {
     describe("Property Signatures", () => {
+      it("Enums", () => {
+        enum Fruits {
+          A = "a",
+          B = "b"
+        }
+
+        const schema = Schema.Struct({
+          a: Schema.Enums(Fruits)
+        })
+        assertNormalizedUrlParams(schema, { a: "a" }, { a: "a" })
+        assertNormalizedUrlParams(schema, { a: "b" }, { a: "b" })
+        assertNormalizedUrlParams(schema, { a: ["a"] }, { a: ["a"] })
+        assertNormalizedUrlParams(schema, { a: ["b"] }, { a: ["b"] })
+      })
+
+      it("TemplateLiteral", () => {
+        const schema = Schema.Struct({
+          a: Schema.TemplateLiteral("a", Schema.String)
+        })
+        assertNormalizedUrlParams(schema, { a: "a" }, { a: "a" })
+        assertNormalizedUrlParams(schema, { a: ["a"] }, { a: ["a"] })
+      })
+
       it("String", () => {
         const schema = Schema.Struct({ a: Schema.String })
         assertNormalizedUrlParams(schema, { a: "a" }, { a: "a" })
@@ -102,6 +125,28 @@ describe("HttpApiBuilder", () => {
     })
 
     describe("Index Signatures", () => {
+      it("Enums", () => {
+        enum Fruits {
+          A = "a",
+          B = "b"
+        }
+
+        const schema = Schema.Record({
+          key: Schema.String,
+          value: Schema.Enums(Fruits)
+        })
+        assertNormalizedUrlParams(schema, { a: "a" }, { a: "a" })
+        assertNormalizedUrlParams(schema, { a: "b" }, { a: "b" })
+      })
+
+      it("TemplateLiteral", () => {
+        const schema = Schema.Record({
+          key: Schema.String,
+          value: Schema.TemplateLiteral("a", Schema.String)
+        })
+        assertNormalizedUrlParams(schema, { a: "a" }, { a: "a" })
+      })
+
       it("String", () => {
         const schema = Schema.Record({
           key: Schema.String,