From 3600fc7965ba8ff36a6a9847dcece64ed96fc06b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Fri, 25 Jul 2025 23:11:41 +0000
Subject: [PATCH] feat(openapi-generator): add support for t.identity codec

This PR adds support for the `t.identity` codec from io-ts in the
openapi-generator package, resolving the issue where consumers could
not use `t.identity` in their API specifications without breaking
OpenAPI spec generation.

Closes Ticket: DX-1606

Co-authored-by: ericcrosson-bitgo <67922293+ericcrosson-bitgo@users.noreply.github.com>
---
 .../openapi-generator/src/knownImports.ts     |  1 +
 .../test/openapi/knownImports.test.ts         | 75 ++++++++++++++++++-
 2 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/packages/openapi-generator/src/knownImports.ts b/packages/openapi-generator/src/knownImports.ts
index fab630d0..d18e88aa 100644
--- a/packages/openapi-generator/src/knownImports.ts
+++ b/packages/openapi-generator/src/knownImports.ts
@@ -137,6 +137,7 @@ export const KNOWN_IMPORTS: KnownImports = {
     brand: (_, arg) => E.right(arg),
     UnknownRecord: () => E.right({ type: 'record', codomain: { type: 'any' } }),
     void: () => E.right({ type: 'undefined' }),
+    identity: (_, arg) => E.right(arg),
   },
   'io-ts-numbers': {
     NumberFromString: () =>
diff --git a/packages/openapi-generator/test/openapi/knownImports.test.ts b/packages/openapi-generator/test/openapi/knownImports.test.ts
index f71af85b..c603e195 100644
--- a/packages/openapi-generator/test/openapi/knownImports.test.ts
+++ b/packages/openapi-generator/test/openapi/knownImports.test.ts
@@ -88,8 +88,8 @@ export const route = h.httpRoute({
   }),
   response: {
     200: {
-      /** 
-       * Testing overridden metadata 
+      /**
+       * Testing overridden metadata
        * @format string
        */
       test: DateFromNumber
@@ -145,3 +145,74 @@ testCase('route with schema with default metadata', ROUTE_WITH_OVERIDDEN_METADAT
     schemas: {},
   },
 });
+
+const ROUTE_WITH_IDENTITY_CODEC = `
+import * as t from 'io-ts';
+import * as h from '@api-ts/io-ts-http';
+
+export const route = h.httpRoute({
+  path: '/identity',
+  method: 'POST',
+  request: h.httpRequest({
+    body: {
+      data: t.identity(t.number)
+    },
+  }),
+  response: {
+    200: {
+      result: t.identity(t.number)
+    }
+  },
+});
+`;
+
+testCase('route with t.identity codec', ROUTE_WITH_IDENTITY_CODEC, {
+  openapi: '3.0.3',
+  info: {
+    title: 'Test',
+    version: '1.0.0',
+  },
+  paths: {
+    '/identity': {
+      post: {
+        parameters: [],
+        requestBody: {
+          content: {
+            'application/json': {
+              schema: {
+                type: 'object',
+                properties: {
+                  data: {
+                    type: 'number',
+                  },
+                },
+                required: ['data'],
+              },
+            },
+          },
+        },
+        responses: {
+          '200': {
+            description: 'OK',
+            content: {
+              'application/json': {
+                schema: {
+                  type: 'object',
+                  properties: {
+                    result: {
+                      type: 'number',
+                    },
+                  },
+                  required: ['result'],
+                },
+              },
+            },
+          },
+        },
+      },
+    },
+  },
+  components: {
+    schemas: {},
+  },
+});