Previously, `validateTarget` only checked if the target element or its
host (if it was a ShadowRoot) was directly contained in the document body.
This failed in cases where the target element was nested inside a shadow
DOM, which itself was attached to the document.
This commit introduces a new helper `isAttachedToDocument` that
traverses through parent nodes and shadow roots to ensure that the
target is ultimately attached to the given document.
Additionally, it now throws a clear error if `document.defaultView` is
missing, indicating that the target document is detached or invalid.
This ensures proper validation of mount targets, including complex
scenarios with shadow roots and iframes.
Before this commit, in some specific situations, owl could skip updating
the DOM, even though it should. Here is what could happen:
- we have a parent component (A) and a child component (B)
- B depends on some reactive props from A
- we update some state that results in A being rendered, and B updated
- before this render is applied to the dom, we update some state again,
which causes A to be rendered again
- however, this new render is such that the B props are now identical,
so it will skip rendering B
- it will then apply the result of the render to the DOM => only A is
updated but B should also be updated!
The problem comes from the fact that Owl committed the props to the
component right after the rendering, to the new props were used in the
props comparison method to decide if B should be updated. This is
incorrect, we should always use the current props to decide what to do,
and only commit them to the component after it has been patched.
Achraf (abz)