CHANGELOG.md

Changelog

Unreleased

Changed

• Promise.defer now uses task.defer instead of waiting for the next Heartbeat. This has different behavior: while the deferred code will still run at the end of the frame, it runs alongside other Lua wake-ups which moves its position in the frame. Also, if you call Promise.defer from inside of an already-deferred thread/Promise, the code will run after your current thread/Promise is finished, during the same frame, rather than on the next frame.
• Promise.delay now wraps task.delay. This shouldn't result in any noticeable behavior changes, but changes in behavior are still possible as we don't have direct control over how Roblox's task scheduler works.

[4.0.0]

Changed

• Promise:finally no longer observes a rejection from a Promise. Calling Promise:finally is mostly transparent now.
  • The Promise returned by Promise:finally resolves or rejects with whatever the parent Promise resolved or rejected with. It will be cancelled if the parent Promise is cancelled.
  • The value returned from the finally handler is discarded now.
  • If the value returned from the finally handler is a Promise, we wait for it to resolve, but we do not use its value.
  • If the value returned from the finally handler is a Promise and it rejects, finally returns the new rejected value.
• Promise:finally no longer counts as a consumer of the parent Promise for cancellation purposes. If all consumers are cancelled and the only remaining callbacks are finally handlers, the Promise is now cancelled.
• The Promise executor thread is now closed with coroutine.close when the Promise is cancelled.
• The Promise executor thread is now closed after the Promise settles (calling resolve or reject).
• Callbacks enqueued with andThen and catch are now dequeued if the Promise returned by andThen/catch is cancelled.
• Calling andThen or catch on an already-cancelled Promise now returns a cancelled Promise instead of returning a rejected Promise
• :await, :expect, and :awaitStatus are no longer backed by BindableEvents, and now use the task library directly, so performance should be better.

[4.0.0-rc.3]

Fixed

• Fix unhandled rejection warning appearing when using :awaitStatus

[4.0.0-rc.2] - 2022-01-02

Fixed

• Fix bug where Promise.fold does not return correct value if there is an unresolved Promise in the passed list (#77)

[3.2.1] - 2022-01-02

Fixed

• Fix bug where Promise.fold does not return correct value if there is an unresolved Promise in the passed list (#77)

[4.0.0-rc.1] - 2021-12-28

Changed

• Promise:finally no longer observes a rejection from a Promise. Calling Promise:finally is mostly transparent now.
  • The Promise returned by Promise:finally resolves or rejects with whatever the parent Promise resolved or rejected with. It will be cancelled if the parent Promise is cancelled.
  • The value returned from the finally handler is discarded now.
  • If the value returned from the finally handler is a Promise, we wait for it to resolve, but we do not use its value.
  • If the value returned from the finally handler is a Promise and it rejects, finally returns the new rejected value.
• Promise:finally no longer counts as a consumer of the parent Promise for cancellation purposes. If all consumers are cancelled and the only remaining callbacks are finally handlers, the Promise is now cancelled.
• The Promise executor thread is now closed with coroutine.close when the Promise is cancelled.
• The Promise executor thread is now closed after the Promise settles (calling resolve or reject).
• Callbacks enqueued with andThen and catch are now dequeued if the Promise returned by andThen/catch is cancelled.
• Calling andThen or catch on an already-cancelled Promise now returns a cancelled Promise instead of returning a rejected Promise
• :await, :expect, and :awaitStatus are no longer backed by BindableEvents, and now use the task library directly, so performance should be better.

Removed

• Promise:done and its associated members have been removed.

[3.2.0] - 2021-12-27

Added

• Add Promise.onUnhandledRejection global event
• Add Promise.retryWithDelay

Changed

• Callable tables are now allowed anywhere that a function are allowed (Promise.new, andThen, etc)

[3.1.0] - 2020-12-01

Added

• Added Promise.fold (#47)

[3.0.1] - 2020-08-24

Fixed

• Make Promise.is work with promises from old versions of the library (#41)
• Make Promise.delay properly break out of the current loop (#40)
• Allow upvalues captured by queued callbacks to be garbage collected when the Promise resolves by deleting the queues when the Promise settles (#39)

[3.0.0] - 2020-08-17

Changed

• Promise.delay now uses os.clock
• Made Promise.delay behavior more consistent when creating new timers in the callback of a timer.

[3.0.0-rc.3] - 2020-07-10

Fixed

• Fixed a bug where queued andThen and catch callbacks did not begin on their own new threads.

[3.0.0-rc.1] - 2020-06-02

Changed

• Runtime errors are now represented by objects. You must call tostring on rejection values before assuming they are strings (this was always good practice, but is required now).
• Yielding is now allowed in Promise.new, andThen, and Promise.try executors.
• Errors now have much better stack traces due to using xpcall internally instead of pcall.
• Stack traces will now be more direct and not include as many internal calls within the Promise library.
• Chained promises from resolve() or returning from andThen now have improved rejection messages for debugging.
• Promise.async has been renamed to Promise.defer (Promise.async references same function for compatibility)
• Promises now have a __tostring metamethod, which returns Promise(Resolved) or whatever the current status is.
• Promise:timeout() now rejects with a Promise.Error(Promise.Error.Kind.TimedOut) object. (Formerly rejected with the string "Timed out")
• Attaching a handler to a cancelled Promise now rejects with a Promise.Error(Promise.Error.Kind.AlreadyCancelled). (Formerly rejected with the string "Promise is cancelled")
• Let Promise:expect() throw rejection objects

Added

• New Promise Error class is exposed at Promise.Error, which includes helpful static methods like Promise.Error.is.
• Added Promise:now() (#23)
• Added Promise.each (#21)
• Added Promise.retry (#16)
• Added Promise.fromEvent (#14)
• Improved test coverage for asynchronous and time-driven functions

Fixed

• Changed Promise.is to be safe when dealing with tables that have an __index metamethod that creates an error.
• Promise.delay resolve value (time passed) is now more accurate (previously passed time based on when we started resuming threads instead of the current time. This is a very minor difference.)

[2.5.1]

• Fix issue with rejecting with non-string not propagating correctly.

[2.5.0]

• Add Promise.tap
• Fix bug with C functions not working when passed to andThen
• Fix issue with Promise.race/all always cancelling instead of only cancelling if the Promise has no other consumers
• Make error checking more robust across many methods.
• Promise.Status members are now strings instead of symbols, and indexing a non-existent value will error.
• Improve stack traces
• Promise.promisify will now turn errors into rejections even if they occur after a yield.
• Add Promise.try
• Add done, doneCall, doneReturn
• Add andThenReturn, finallyReturn
• Add Promise.delay, promise:timeout
• Add Promise.some, Promise.any
• Add Promise.allSettled
• Promise.all and Promise.race are now cancellable.

[2.4.0]

• Promise.is now only checks if the object is "andThennable" (has an andThen method).

[2.3.1]

• Make unhandled rejection warning trigger on next Heartbeat

[2.3.0]

• Remove Promise.spawn from the public API.
• Promise.async still inherits the behavior from Promise.spawn.
• Promise.async now wraps the callback in pcall and rejects if an error occurred.
• Promise.new has now has an explicit error message when attempting to yield inside of it.

[2.2.0]

• Promise.promisify now uses coroutine.wrap instead of Promise.spawn

[2.1.0]

• Add finallyCall, andThenCall
• Add awaitValue

[2.0.0]

• Add Promise.race
• Add Promise.async
• Add Promise.spawn
• Add Promise.promisify
• finally now silences the unhandled rejection warning
• onCancel now returns if the Promise was cancelled at call time.
• Cancellation now propagates downstream.
• Add Promise:awaitStatus
• Calling resolve with a Promise while the resolving Promise is cancelled instantly cancels the passed Promise as an optimization.
• finally now passes the Promise status as a parameter.