From 4586cc5a90d5752b0fbe6e5221463ed6ec56858d Mon Sep 17 00:00:00 2001
From: David Duque <david.f.s.duque@tecnico.ulisboa.pt>
Date: Sat, 2 May 2020 19:24:05 +0100
Subject: [PATCH] Use pcall() on Promise.is when looking for the .andThen
 function

Some tables might have strict metatables that error if a non-existant
member is indexed, causing the chain to fail.
---
 lib/init.lua | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/init.lua b/lib/init.lua
index 1ab7e14..6687e66 100644
--- a/lib/init.lua
+++ b/lib/init.lua
@@ -471,7 +471,11 @@ function Promise.is(object)
 		return false
 	end
 
-	return type(object.andThen) == "function"
+	local ok, isPromise = pcall(function()
+		return type(object.andThen) == "function"
+	end)
+
+	return ok and isPromise
 end
 
 --[[