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().
--- 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;
--- 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