# HG changeset patch
# User Matthew Wild <mwild1@gmail.com>
# Date 1665161006 -3600
# Node ID eb9814372c5406053568df9cb02f37655234aae7
# Parent  7b9de8109a909a4eb5494cfdcdfdaf4b8f013cfa
util.promise: Remove some redundant checks, add tests confirming redundancy

This lines don't appear to do anything useful, and all tests pass when they
are removed. Discovered via mutation testing.

I added extra tests to exercise this code, because I wasn't certain that there
were no side-effects caused by removal. Everything appears to be fine, thanks
to the "pending" check at the start of promise_settle().

diff -r 7b9de8109a90 -r eb9814372c54 spec/util_promise_spec.lua
--- a/spec/util_promise_spec.lua	Fri Oct 07 17:01:35 2022 +0100
+++ b/spec/util_promise_spec.lua	Fri Oct 07 17:43:26 2022 +0100
@@ -30,6 +30,27 @@
 		r("foo");
 		assert.spy(cb).was_called(1);
 	end);
+	it("ignores resolve/reject of settled promises", function ()
+		local res, rej;
+		local p = promise.new(function (resolve, reject)
+			res, rej = resolve, reject;
+		end);
+		local cb = spy.new(function (v)
+			assert.equal("foo", v);
+		end);
+		p:next(cb, cb);
+		assert.spy(cb).was_called(0);
+		res("foo");
+		assert.spy(cb).was_called(1);
+		rej("bar");
+		assert.spy(cb).was_called(1);
+		rej(promise.resolve("bar"));
+		assert.spy(cb).was_called(1);
+		res(promise.reject("bar"));
+		assert.spy(cb).was_called(1);
+		res(promise.resolve("bar"));
+		assert.spy(cb).was_called(1);
+	end);
 	it("allows chaining :next() calls", function ()
 		local r;
 		local result;
diff -r 7b9de8109a90 -r eb9814372c54 util/promise.lua
--- a/util/promise.lua	Fri Oct 07 17:01:35 2022 +0100
+++ b/util/promise.lua	Fri Oct 07 17:43:26 2022 +0100
@@ -57,9 +57,7 @@
 end
 
 local function new_resolve_functions(p)
-	local resolved = false;
 	local function _resolve(v)
-		if resolved then return; end
 		resolved = true;
 		if is_promise(v) then
 			v:next(new_resolve_functions(p));
@@ -69,8 +67,6 @@
 
 	end
 	local function _reject(e)
-		if resolved then return; end
-		resolved = true;
 		if promise_settle(p, "rejected", next_rejected, p._pending_on_rejected, e) then
 			p.reason = e;
 		end