Lift Framework 3.0-M3

This release brings quite a few changes, mostly as small improvements and bug fixes over M2. M3 is the next “stable snapshot” release, meaning that we've got some more big potentially-breaking changes in the pipeline and we're putting M3 out so that if you're on the SNAPSHOT build and those changes have negative effects, you can fall back on M3 and continue working.

Without further ado, here's a list of the changes that went in between M2 and M3 (note that they are not all super well-documented; more documentation will come before the 3.0 final release, but in the meantime please ask any questions you may have on the Lift mailing list):

Deprecations

• (#1668) Much of TimeSpan's functionality has been deprecated. TimeSpan conflated several different concepts, including DateTime, Duration, and Period, which did not have the same semantics. As a result, there were corner cases where it could behave in very unexpected ways. In order to fix this, we've deprecated TimeSpan functionality for all uses that are not as a simple millisecond Duration. This deprecation takes effect for the final release of Lift 3.0, which means the functionality in question won't be removed until Lift 3.1 at the earliest. Big big thanks to @arkadius for spotting this issue while trying to clean up specs, and taking point on adding the various deprecations.

Improvements

• (#1619) Added a MessageCometActor which is designed solely for pushing what were until now called partialUpdates. This is the beginning of a reworking of the comet API into a base MessageCometActor that handles just the messaging facet of comets, and a CometActor that works like the current one does. In particular, MessageCometActor does not have an overridable render method, as it is not expected to render itself—only to push updates. If your comet actor uses render, make sure that a call to render can replace any previous rendering + any partial updates since then. That is to say, rendering at time t_0 and then sending partial updates at t_1, t_2, and t_3 should produce the same result as rendering at time t_4. This is because calling render clears the list of partial updates, so if that condition does not hold, you can lose information. In these cases, please render separately and use MessageCometActor. In MessageCometActor, you can and should use pushMessage instead of partialUpdate to send a message to the client. We'll expand further on the distinction once we've fleshed out the APIs a bit more.
• (#1619) Rename devMode on CometActor to alwaysReRenderOnPageLoad to clarify what its purpose is.
• (#1652) Lift now supports a LiftRules.contentParsers rule that can be used to define parsers for templates, which the template loading pipeline can then use to load templates of various types. Out of the box, we provide the existing HTML and Markdown parsers, but this can easily be used to add, e.g., asciidoc support. The Scaladocs for LiftRules.contentParsers and the ContentParser class should provide a good guide to getting started, and an example of adding asciidoc support can be seen in @joescii's blog source code.
• (#1609) Using toSingleBox on a List[Box] that contains Failures now produces a ParamFailure whose chain is set up so that you can call failureChain to get all of those failures. You can still use the ParamFailures param to get the original list of boxes.
• (#1663) HLists are now covariant in their type parameters. Lift provides a lightweight HList in lift-util; this is a small improvement to it. More comprehensive (but also heavier and harder on the compiler) HLists are available using shapeless, as well.
• (#1649) Session ids are no longer emitted into page markup.
• (#1650) The scaladocs in lift-common have seen a lot of general cleanup and improvement.
• (#1656, #1658) More reliable specs in a few corners of the framework, thanks to @arkadius.

Bug fixes

• (#1619) Lift 3.0 milestone builds until now had a few comet-related bugs. Amongst other things, they could unexpectedly lose partial updates and call render more than once when a page was initially rendered. Most of these issues should now be fixed.
• (#1619) lastListenerTime is now accurate, where before it was never updated.
• (#1639) When throwing a ResponseShortcutException during an AJAX request handler, we now correctly serve the specified response. Before, only those with a location attached were handled, by serving a JS redirect command. Now you can serve any response you want—though those that have a location associated will always result in a JS redirect command for now.
• (#1640) The email regex in ProtoRules is now case insensitive and includes support for TLDs longer than 4 characters.
• (#1646) Lift 3.0-M2 introduced the ability to serve new comet actors via AJAX; however, doing this from within an AJAX handler bound inside a comet, or using a partialUpdate, had a few issues that prevented it from working correctly. These are now fixed.
• (#1646) S.appendJs from inside a comet's message handler could occasionally produce double execution of the JS, and other times could simply not work. S.appendJs should now always work and correctly execute the JS only once when used from within a comet's message handler.
• (#1648) Fix use of S.oneShot and S.callOnce with ajaxOnSubmit.
• (#1664) The LAFuture singleton's collect and collectAll functions, when given an empty list, now return an LAFuture that is immediately satisfied with an empty list. Before, these would return a future that would never be satisfied. Thanks to @arkadius.

Removals

• (#1619) Introduced in the first milestone of Lift 3.0, CometActor's lastWhenDeltaPruner has been removed as it could present timing issues that were difficult to fix. It may make a reappearance before Lift 3 goes final, depending on whether we figure out how to implement it more robustly.