fix: ctx.assert() throws HttpError instances (#1925)

lib/context.js

@@ -6,13 +6,37 @@
 
 const util = require('util')
 const createError = require('http-errors')
+const { HttpError } = require('http-errors')
 const httpAssert = require('http-assert')
 const delegate = require('delegates')
 const statuses = require('statuses')
 const Cookies = require('cookies')
 
 const COOKIES = Symbol('context#cookies')
 
+// Wrap http-assert to ensure thrown errors are instances of koa's HttpError.
+// http-assert uses its own http-errors dependency, so instanceof checks fail.
+// See: https://github.com/koajs/koa/issues/1925
+function wrappedAssert (value, status, msg, opts) {
+  try {
+    httpAssert(value, status, msg, opts)
+  } catch (err) {
+    if (err instanceof HttpError) {
+      throw err
+    }
+    // Re-throw using koa's createError so instanceof HttpError works
+    throw createError(err.status || err.statusCode || 500, err.message || msg, opts)
+  }
+}
+
+wrappedAssert.fail = httpAssert.fail
+wrappedAssert.equal = httpAssert.equal
+wrappedAssert.notEqual = httpAssert.notEqual
+wrappedAssert.ok = httpAssert.ok
+wrappedAssert.strictEqual = httpAssert.strictEqual
+wrappedAssert.notStrictEqual = httpAssert.notStrictEqual
+wrappedAssert.deepEqual = httpAssert.deepEqual
+
 /**
  * Context prototype.
  */
@@ -69,7 +93,7 @@ const proto = module.exports = {
    * @api public
    */
 
-  assert: httpAssert,
+  assert: wrappedAssert,
 
   /**
    * Throw an error with `status` (default 500) and