Previously, refs could get set to null incorrectly, or could stay set
when they shouldn't. This was caused by the fact that singleRefSetter
and multiRefSetters are created on every render, meaning that any render
that did not affect the status of the ref (mounted or not), would
overwrite the previous ref setter, including its closure, causing the
captured `_el` or `count` to be lost. This means that on a subsequent
render that did affect the status of the ref, the singleRefSetter would
consider that it did not set the ref, and so shouldn't unset it, causing
it to incorrectly stay keep the element, while in multiRefSetter, the
opposite problem occured: the count would be 0 on removal, causing it to
believe that it was the first call in the corresponding patch that
affected the ref, when in fact, the closure is already stale, because it
was created from the previous render, and the fresh multiRefSetter from
the latest render may already have been called by an element with that
ref that came earlier in the template.
This commit changes the ref setting strategy to work around the issue of
stale closures: we define a setRef method on ComponentNode that is
always called, this method ignores calls with `null`, meaning that the
refs object on the ComponentNode never reverts to a null value for any
key. Instead, the useRef hook will check whether the element that the
ref points to is still mounted, and return null if not.
Have a t-ref on a DOM node with a t-key.
Change the t-key.
Before this commit, the old block removed its element from the component's refs *after*
the new block had been mounted, meaning that in effect, the resulting
ref at the end of the whole patch was null.
After this commit, we only remove an element from the component's ref if that very same
element was indeed the ref. (otherwise it means someone else has changed the ref.)
This commit makes it so that when an error occurs in an owl app and none
of the registered error handlers are able to handle it, we rethrow the
error instead of just logging it to the console and swallowing it. This
allows users of owl to handle errors that happen in owl applications by
using event listeners for error and unhandledrejection events on the
window.
Samuel Degueldre