[OpenAPI3 Emitter] Add option to map safeint to double-int

.chronus/changes/safe-int-openapi3-2024-1-17-0-53-2.md

@@ -0,0 +1,21 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: breaking
+packages:
+  - "@typespec/openapi3"
+---
+
+`safeint` scalar now map to `type: integer, format: double-int`. To revert to the previous output of `type: integer, format: int64`. You can either:
+
+1. Use the `safeint-as-int64` option:
+  ```yaml
+  # tspconfig.yaml
+  options:
+     "@typespec/openapi3":
+        safeint-as-int64: true
+  ```
+2. Apply `@encode("int64", int64)` on every usage of safeint(or create a new scalar)
+  ```tsp
+  @encode("int64", int64)
+  scalar int64Safeint extends safeint;
+  ```

packages/openapi3/src/schema-emitter.ts

@@ -699,7 +699,7 @@ export class OpenAPI3SchemaEmitter extends TypeEmitter<
       case "int64":
         return { type: "integer", format: "int64" };
       case "safeint":
-        return { type: "integer", format: "int64" };
+        return { type: "integer", format: "double-int" };
       case "uint8":
         return { type: "integer", format: "uint8" };
       case "uint16":

packages/openapi3/test/primitive-types.test.ts

@@ -13,7 +13,7 @@ describe("openapi3: primitives", () => {
       ["int16", { type: "integer", format: "int16" }],
       ["int32", { type: "integer", format: "int32" }],
       ["int64", { type: "integer", format: "int64" }],
-      ["safeint", { type: "integer", format: "int64" }],
+      ["safeint", { type: "integer", format: "double-int" }],
       ["uint8", { type: "integer", format: "uint8" }],
       ["uint16", { type: "integer", format: "uint16" }],
       ["uint32", { type: "integer", format: "uint32" }],