[backport] fix: remove satisfies keyword from type validation to preserve old TS compatibility (#83071)

Author: bgub

packages/next/src/server/lib/router-utils/typegen.ts

@@ -446,10 +446,13 @@ export function generateValidatorFile(
             : type
         return `// Validate ${filePath}
 {
+  type __IsExpected<Specific extends ${typeWithRoute}> = Specific
   const handler = {} as typeof import(${JSON.stringify(
     importPath.replace(/\.tsx?$/, '.js')
   )})
-  handler satisfies ${typeWithRoute}
+  type __Check = __IsExpected<typeof handler>
+  // @ts-ignore
+  type __Unused = __Check
 }`
       })
       .join('\n\n')

test/e2e/app-dir/typed-routes-validator/typed-routes-validator.test.ts

@@ -13,7 +13,7 @@ describe('typed-routes-validator', () => {
   it('should generate route validation correctly', async () => {
     const dts = await next.readFile('.next/types/validator.ts')
     // sanity check that dev generation is working
-    expect(dts).toContain('handler satisfies AppPageConfig')
+    expect(dts).toContain('const handler = {} as typeof import(')
   })
 
   if (isNextStart) {
@@ -51,7 +51,7 @@ describe('typed-routes-validator', () => {
 
       expect(exitCode).toBe(1)
       expect(cliOutput).toMatch(
-        /Type error: Type 'typeof import\(.*\)' does not satisfy the expected type 'AppPageConfig<"\/invalid">'/
+        /Type error: Type 'typeof import\(.*' does not satisfy the constraint 'AppPageConfig</
       )
     })
 
@@ -111,7 +111,7 @@ describe('typed-routes-validator', () => {
 
       expect(exitCode).toBe(1)
       expect(cliOutput).toMatch(
-        /Type error: Type 'typeof import.*does not satisfy the expected type 'RouteHandlerConfig<"\/invalid">'/
+        /Type error: Type 'typeof import\(.*' does not satisfy the constraint 'RouteHandlerConfig</
       )
     })
 
@@ -132,7 +132,9 @@ describe('typed-routes-validator', () => {
       await next.deleteFile('app/invalid-2/route.ts')
 
       expect(exitCode).toBe(1)
-      expect(cliOutput).toContain(`Types of property 'POST' are incompatible.`)
+      expect(cliOutput).toMatch(
+        /Type error: Type 'typeof import\(.*' does not satisfy the constraint 'RouteHandlerConfig</
+      )
     })
 
     it('should pass type checking with valid layout exports', async () => {
@@ -174,7 +176,7 @@ describe('typed-routes-validator', () => {
 
       expect(exitCode).toBe(1)
       expect(cliOutput).toMatch(
-        /Type error: Type 'typeof import\(.*does not satisfy the expected type 'LayoutConfig<"\/invalid">'/
+        /Type error: Type 'typeof import\(.*' does not satisfy the constraint 'LayoutConfig</
       )
     })
 
@@ -220,7 +222,7 @@ describe('typed-routes-validator', () => {
 
       expect(exitCode).toBe(1)
       expect(cliOutput).toMatch(
-        /Type error: Type 'typeof import\(.*does not satisfy the expected type 'ApiRouteConfig'/
+        /Type error: Type 'typeof import\(.*' does not satisfy the constraint 'ApiRouteConfig'/
       )
     })
   }