Previously, if the value of a t-component directive changed, but there
was already a scheduled render for the component before that change, the
rendering of the existing component would get delayed (as it should),
but after the parent's rendering was complete, the old component which
will be destroyed during the patch would still get rendered, despite
being stale. This can cause crashes if that component relies on state
that no longer exists.
This was caused by the fact that when rendering, we check the parent
chain for an active render, and also check that the component still
exists in the parent's fiber childrenMap (ie, we know that the upcoming
patch is not about to destroy the component). To do this, we use the
component's parentKey, but in the case of t-component, the parentKey for
both possible components is the same, causing the stale component to
incorrectly believe that it's not about to be destroyed, by finding the
next component in the childrenMap under the same key.
This commit fixes that by prepending the component's name to the
parentKey, meaning that if the value of the t-component changes, so will
the key, and the render will be further delayed until the new state is
patched, at which point the stale component will be destroyed and the
following attempt to render will be cancelled as expected.
The choice to use the component's name is to simplify the
implementation, this means that if using t-component and switching
between components that have the same class name, this protection will
not work. The alternative would be to generate a unique id for the
component class, eg with a WeakMap, but this both complicates the
implementation and adds runtime overhead, for a case that is likely
extremely rare. We are open to refine the implementation should this
problem occur in practice.
Before this commit, the generated code for the component directive was
using the current context as the place to look for static informations
(such as the sub components). However, it is not entirely correct, since
the current context may be different than the current component (which
is easily accessed by using the this variable).
Also, while doing this, we fix some issues in the t-set directive, which
as calling lazy values with the wrong this.
Have a GrandParent which controls whether one of its GrandChildren is displayed or not.
First, the GrandChild is displayed. Then, change the state of the GrandParent in order to kill
the GrandChild.
Before this commit the GrandChild is only removed from the DOM, as bdom correctly works.
But it is not destroyed.
After this commit, the GrandChild is correctly destroyed.
Every use case involving some sort of key set on a component would give birth to a leak in an async context:
- If a key of a component changed, the outdated one was never destroyed.
- destroyed component were never removed from their parent's reference map.
This commit solves both issues, that are tightly linked anyway.
This means that unrelated ids (eg the id of a template, variable or key)
not longer share the same incrementing counter, meaning that you no
longer see a variable named "v2" unless another variable "v1" was
generated previously, this is also true for block data.
t-out automatically escaped content when it is a string not marked
with the `markup` function
t-out renders the raw content if it is a Block, or if it has been marked
with the `markup` funtion.
t-esc has been kept since it is safe and is optimized to render text nodes.
all t-raw calls are in fact the same as t-out.
We reintroduce the possibility to mount the app in first position in
a target. The option "self" has been dropped since it is now possible
for a component to have several top level nodes.
This commit reintroduces some tests for the t-set directive and make
them pass. For that, it was necessary to adapt the qweb compiler in
order to get the following behaviors:
A t-set can affect parent contexts (up to the first parent tagged as
boundary) when the key changed is found in one of the parent contexts.
Some context are marked as boundaries in such a way that
- rendering contexts (e.g. components) cannot be modified via a t-set.
- a t-set in a t-call body or in a called template can never change a
context above the t-call context.
Code prettification has been done.
Snapshots have been modified.
We add some test for the t-on directive.
For making them pass, it was necessary to change the code produced by
compileTForeach: the const declaration is not done by using generateId
and there was some conflict with the variable names produced in
captureExpression. Consequently, many snapshots had to be changed.
Code prettification has been done too.
Samuel Degueldre