From e33a0f4682374faadc0a6ef5bb02b16bcc3f2d88 Mon Sep 17 00:00:00 2001
From: Andrea Giammarchi <andrea.giammarchi@gmail.com>
Date: Wed, 2 Jul 2025 18:54:21 +0200
Subject: [PATCH] webassembly/objpyproxy: Avoid throwing on symbol or iterator
 has-check.

JavaScript code uses "Symbol in object" to brand check its own proxies, and
such checks should also work on the Python side.

Signed-off-by: Andrea Giammarchi <andrea.giammarchi@gmail.com>
---
 ports/webassembly/objpyproxy.js              | 6 ++++++
 tests/ports/webassembly/py_proxy_has.mjs     | 2 ++
 tests/ports/webassembly/py_proxy_has.mjs.exp | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/ports/webassembly/objpyproxy.js b/ports/webassembly/objpyproxy.js
index 3b94f8aadc..0eafd0dec5 100644
--- a/ports/webassembly/objpyproxy.js
+++ b/ports/webassembly/objpyproxy.js
@@ -148,6 +148,12 @@ const py_proxy_handler = {
         };
     },
     has(target, prop) {
+        // avoid throwing on `Symbol() in proxy` checks
+        if (typeof prop !== "string") {
+            // returns true only on iterator because other
+            // symbols are not considered in the `get` trap
+            return prop === Symbol.iterator;
+        }
         return Module.ccall(
             "proxy_c_to_js_has_attr",
             "number",
diff --git a/tests/ports/webassembly/py_proxy_has.mjs b/tests/ports/webassembly/py_proxy_has.mjs
index 8881776fdb..37df0ae179 100644
--- a/tests/ports/webassembly/py_proxy_has.mjs
+++ b/tests/ports/webassembly/py_proxy_has.mjs
@@ -9,3 +9,5 @@ x = []
 const x = mp.globals.get("x");
 console.log("no_exist" in x);
 console.log("sort" in x);
+console.log(Symbol.toStringTag in x);
+console.log(Symbol.iterator in x);
diff --git a/tests/ports/webassembly/py_proxy_has.mjs.exp b/tests/ports/webassembly/py_proxy_has.mjs.exp
index 1d474d5255..7565230c01 100644
--- a/tests/ports/webassembly/py_proxy_has.mjs.exp
+++ b/tests/ports/webassembly/py_proxy_has.mjs.exp
@@ -1,2 +1,4 @@
 false
 true
+false
+true