Currently, when a component used is not properly registered, we have a warning and the vnode type is set to a Comment type in DEV mode. But in prod mode, we have no default value, making such an application broken and throw a strange error (`can not read _isSuspense of undefined`).
This commit avoids such an error in prod mode (as it is currently the case in Vue 2.x).
BREAKING CHANGE: `RendererOptions.patchProp` arguments order has changed
The `prevValue` and `nextValue` position has been swapped to keep it
consistent with other functions in the renderer implementation. This
only affects custom renderers using the `createRenderer` API.
BREAKING CHANGE: adjust attr fallthrough behavior
Updated per pending RFC https://github.com/vuejs/rfcs/pull/137
- Implicit fallthrough now by default only applies for a whitelist
of attributes (class, style, event listeners, a11y attributes, and
data attributes).
- Fallthrough is now applied regardless of whether the component has
explicitly declared props. (close#749)
BREAKING CHANGE: revert setup() result reactive conversion
Revert 6b10f0c & a840e7d. The motivation of the original change was
avoiding unnecessary deep conversions, but that can be achieved by
explicitly marking values non-reactive via `markNonReactive`.
Removing the reactive conversion behavior leads to an usability
issue in that plain objects containing refs (which is what most
composition functions will return), when exposed as a nested
property from `setup()`, will not unwrap the refs in templates. This
goes against the "no .value in template" intuition and the only
workaround requires users to manually wrap it again with `reactive()`.
So in this commit we are reverting to the previous behavior where
objects returned from `setup()` are implicitly wrapped with
`reactive()` for deep ref unwrapping.
BREAKING CHANGE: custom directive bindings no longer expose instance
This is a rarely used property that creates extra complexity in
ensuring it points to the correct instance. From a design
perspective, a custom directive should be scoped to the element and
data it is bound to and should not have access to the entire
instance in the first place.
BREAKING CHANGE: replae `watch(fn, options?)` with `watchEffect`
The `watch(fn, options?)` signature has been replaced by the new
`watchEffect` API, which has the same usage and behavior. `watch`
now only supports the `watch(source, cb, options?)` signautre.
BREAKING CHANGE: `watch` behavior has been adjusted.
- When using the `watch(source, callback, options?)` signature, the
callback now fires lazily by default (consistent with 2.x
behavior).
Note that the `watch(effect, options?)` signature is still eager,
since it must invoke the `effect` immediately to collect
dependencies.
- The `lazy` option has been replaced by the opposite `immediate`
option, which defaults to `false`. (It's ignored when using the
effect signature)
- Due to the above changes, the `watch` option in Options API now
behaves exactly the same as 2.x.
- When using the effect signature or `{ immediate: true }`, the
intital execution is now performed synchronously instead of
deferred until the component is mounted. This is necessary for
certain use cases to work properly with `async setup()` and
Suspense.
The side effect of this is the immediate watcher invocation will
no longer have access to the mounted DOM. However, the watcher can
be initiated inside `onMounted` to retain previous behavior.
