Commit Graph

655 Commits

Author SHA1 Message Date
Géry Debongnie 27629cedfa [IMP] qweb: allow multiclasses in t-att-class object form
the low level method htmlelement.classList.add does not accept multiple
classes in one string, which is why, in owl, the expression

`<div t-att-class="{'a b c': value}" />`

did not work as one might expect. It is however very convenient in real
life templates, so this commit improve owl by adding support for this
feature.

closes #813
2021-07-05 10:09:23 +02:00
Géry Debongnie 3a93370ab6 [FIX] component: do not shadow the initial error in some cases
Before this commit, the error handling code simply destroyed the
application whenever an unhandled error occured in the owl rendering
process. This is perfectly fine, except that since the application is
potentially corrupted, the destroy code may crash as well. We simply
catch those errors to avoid shadowing the main issue.

closes #866
2021-07-05 10:09:23 +02:00
Géry Debongnie a6bb4d8ee1 [FIX] component: make sure default slot is applied
Before this commit, owl was erroneously defining default slots in most
cases, even though they are empty. The problem occurs when the content
of a component slots is a t-set-slot, and we remove that, then use the
rest as default slots, even though it is only reduced to a set of text
nodes.

With this commit, we only consider the content as default content if it
is not only a sequence of text nodes containing only spaces.

closes #882
2021-07-05 10:09:23 +02:00
Géry Debongnie caf842c482 [FIX] component: fix scoping issue in nested loops
The templates contained in a slot have to be rendered with the current
scope, but during the rendering of the sub component, which happens
later (after the willStart for the sub component). Therefore, we need to
save the scope that should be used for the slots, so we can access the
proper variables. This was done using an Object.assign() statement,
which is actually only a shallowclone for the own properties.

In this commit, we properly copy all the properties for the current
scope, even those contained in the prototype.

closes #855
2021-07-05 10:09:23 +02:00
Géry Debongnie 1b513a1637 [FIX] qweb: add support for t-att-value on <select> tags
Before this commit, it was not possible to set the value of a select tag
by using the t-att-value attribute.

Doing so is not actually trivial because of the way the vdom works: it
processes the node attributes before its children are created, which
means that the vdom code tries to set the initial value of the select
before its children are created, which means that it is ignored. To make
it work, I added a node create hook which is called after the children
are completely processed.

closes #873
2021-07-05 10:09:23 +02:00
Géry Debongnie 52a200878a [FIX] qweb: add support for t-att-value on textareas
The code did not treat textareas in the same way as inputs. As a result,
using t-att-value on a textarea did not work.

closes #872
2021-07-05 10:09:23 +02:00
Géry Debongnie dabe7f9bfa [FIX] qweb: properly parse short object description
Before this commit, using an expression such as "{machin}" was compiled
in qweb into "{scope['machin']}" which is not valid.

With this commit, we instead transform it into "{machin:
scope['machin']}".

closes #885
2021-07-02 14:20:13 +02:00
Michael Mattiello (mcm) d08ea63565 [IMP] directive: make props override t-props
Before this commit, props and t-props were computed like
`Object.assign(props, t_props)`.
Now, it computes like `Object.assign(t_props, props)` so props will
override t-props.

closes https://github.com/odoo/owl/issues/886
2021-07-02 11:50:23 +02:00
Sébastien Theys 7ebe0da962 [IMP] component: add support for callable expression in event handler 2021-07-01 12:26:23 +02:00
Géry Debongnie 922eb7cd98 [FIX] component: propagate errors to parent
Before this commit, the error handling process was too naive: once an
error occurs in a rendering, owl catches it, looks for a component that
implements the catchError method, then calls it.

However, in real life, we sometimes need to rethrow that error (or
another one) to propagate the error to some parent handler. This error
needs to be handled by the closest parent component that implements
catchError.

This is what this commit implements: it wraps the catchError call in a
try/catch, then in case of errors, try to handle it by a parent.
2021-06-18 10:34:09 +02:00
Géry Debongnie 1a6b26c8c6 [REF] cleanup: prettier 2021-06-10 10:23:48 +02:00
Lucas Perais (lpe) d67d295eaa [FIX] qweb, t-call: t-call nested in t-slot
Have a t-call within a t-set-slot of a component.
The called template has a t-component directive.

It should be like:

```xml
<t t-name="Zero">
  <Slotted>
    <t t-call="someTemplate" />
  </Slotted>
</t>

<t t-name="someTemplate">
  <SomeComponent />
</t>
```

Before this commit, the parent of SomeComponent was the Zero component

After this commit, the parent of SomeComponent is the Slotted Component as it should be

closes #862
2021-06-10 10:00:22 +02:00
Géry Debongnie 3a461e1dd1 [IMP] qweb: add support for t-tag directive
Very useful in some cases, when one needs to define a generic component.

closes #721
2021-06-04 14:11:31 +02:00
Samuel Degueldre acac9d1741 [FIX] router: add support for more arbitrary param placements in paths
Before this commit, params in paths had to be be between slashes and
comprise the entirety of the contents between those slashes (eg:
`/books/{{id}}/{{name}}`)

This is unnecessarily restrictive. This commit removes this restriction,
which allows for paths such as:
- `/books/{{id}}-{{name}}`
- `#books&id={{id}}&name={{name}}`

among others

closes #858
2021-05-19 12:25:58 +02:00
Samuel Degueldre e646eb697e [FIX] qweb: fix order of lookup in t-component directive
Previously, the order of resolution was:
- components defined on the class of the current component
- components defined on the QWeb instance
- the current instance's context

This is unnatural because it doesn't go from most specific to least, as
the current instance's context is the most specific. This is also
fragile, as adding components to the QWeb instance can break unrelated
components.

This commit fixes that by making the lookup start with the current
component's context instead
2021-05-18 09:58:30 +02:00
Géry Debongnie 0290f63ba3 [FIX] component: various issues while mounting manually components
The initial problem solved by this commit is that it was possible to get
into a situation where a mounting/rendering was started, then the component was
updated, but then another mounting operation begins, and it tries to
reuse the previous rendering operation, which is no longer uptodate.

The underlying issue is that Owl did not track properly the various
internal state change of a component.  These issue should be solved by
the introduction of the status enum, which currently tracks 6 possible
states:

- CREATED
- WILLSTARTED
- RENDERED
- MOUNTED
- UNMOUNTED
- DESTROYED

This status number replaces the isMounted and isDestroyed boolean flags.
It has the advantage of making sure that the component is in a
consistent state (it is no longer possible to be destroyed and mounted,
for example)

Another advantage is that it gives us an easy way to track the fact that
a component has been rendered, but is not in the DOM.  This is a subtle
situation where some various events can happen, and we need to be able
to react to that case.

Note that there is a change of behaviour: if a component is mounted in a
specific target, then before the mounting is complete, the component is
mounted in another target, we no longer reject the first mounting
operation.
2021-02-08 10:59:28 +01:00
Géry Debongnie 76735410f8 [FIX] qweb: prevent issue with builtin object properties
The QWeb expression parser use an object as a mapping between some
strings and the desired output in the compiled template.  However, as we
should all know, objects are not Maps, they have some additional
properties, such as "constructor" or "hasOwnProperty".

The simple solution is to make sure the mapping object does not have
anything in its prototype chain to pollute its purpose.

closes #835
2021-02-04 09:07:26 +01:00
Géry Debongnie 19a47a7001 [IMP] component: add setup lifecycle hook 2021-02-03 15:32:38 +01:00
Géry Debongnie 398f9f4e53 [IMP] component: can trigger event handlers even if unmounted
From the beginning, Owl was designed to only call event handler on
components that are mounted in the DOM.  The main benefit is that if a
component is destroyed, we are guaranteed to not execute any useless (or
potentially dangerous code).

However, there is one downside: if a component tree is being mounted,
and a child component trigger an event in its mounted hook, then it
cannot be caught by the parent, since the parent is technically not yet
mounted.

This may not be a good situation, but the point is that Owl
unnecessarily prevent the handler to be called.

We can fix this issue by simply checking if the component is not destroyed
instead of checking that it is mounted.

closes #809
2021-02-03 14:46:18 +01:00
Géry Debongnie dfc782599b [FIX] crash when rendering component before mounting
This commit makes sure that Owl does not crash when a component is
created, then updated (for example, with a (observed) state change), and
then, some moment later, mounted.

The initial render is not useful, because it is not linked to a mounting
action anyway.  And it caused issues such as a crash when Owl tried to
patch it to a non existing target
2021-01-19 15:26:15 +01:00
Géry Debongnie 1a20cc57de [FIX] component can be updated while detached from the main DOM
This commit tries to improve the interactions involving unmounted
components, or components mounted in an htmelement which is detached
from the main DOM, and rendering actions.

The main example is mounting a component in detached div, to prepare all
children.  If we just mount the component, it will work as expected: the
full component tree is rendered in memory, and ready to be really
mounted at the desired target.

However, if before doing that, we update the component and call render
on it (for example, with a change in an observed state), then this
rendering will be ignored, and therefore, the full subcomponent tree is
not uptodate.

This commit will also solve another issue in the compatibility layer in
odoo: in the form renderer, we mount components with the adapter in a
div, which is not yet attached to the DOM. We then manually call the
mounted hook when on_attach_callback is called.  This means that before
this commit, any change to the components between the initial rendering
and the call to mounted will be ignored.

As a bonus, this commit has the effect of bringing closer the semantics
of render and mount operations, which is certainly good.

closes #823
2021-01-14 09:05:05 +01:00
Géry Debongnie 4a96eff3c6 [FIX] store: properly call onUpdate functions in some cases
Before this commit, the following scenario could happen:

Suppose that we have a parent component A, connected to a store,
 and a child component B, also connected to the store and using
the onUpdate feature.

Then, we remount the A component in some other places and a
rendering is initiated in A.  We immediately update the store state.
What happens next is:

- rendering A is done, A internal revid is updated
- store update A (but nothing is done because the state change here
  does not modify A)
- rendering B is done (from parent), B internal revid is updated
- store update B, notice internal revid is updated, does not call the
  onUpdate function

We then have the B component which has not its internal state updated,
because we did not call its onUpdate function.

The solution is to move the onUpdate call in a "preupdate" event, to be
sure that it is called everytime the store is updated.

closes #816
2021-01-08 15:05:07 +01:00
Géry Debongnie d043d47754 [FIX] component: propagate correct info when reusing fibers
In some cases, a rendering initiated in some component is then remapped
into a larger rendering initiated by some parent.

If we have some components which implement shouldUpdate to return false,
then the following scenario can happen:

- some parent component is mounted (which triggers a rendering with
force: true => bypass the shouldUpdate)
- some sub component is updated and rerendered, AFTER the previous
rendering goes through it
- the sub component notices that there is an ongoing rendering, and
  remaps itself in the parent rendering

Before this commit, the new fiber in the subcomponent does not have
force flag set to true, so the new rendering for the subcomponent does
not go through its own children (if they have shouldUpdate=false)

Another more complex kind of scenaria can happen when a remapped
rendering happen with sub components with dynamic shouldUpdate. The
problem is the same at the end: the new rendering should ignore the
shouldUpdate, to make sure we have the last correct information.

With this commit, we make sure that the flag of the new fiber is set to
true.

closes #818
2021-01-07 10:08:29 +01:00
Géry Debongnie bb64e87634 [FIX] store: properly render, even if shouldupdate is implemented
Before this commit, an unwanted behaviour happened when using components
with shouldUpdate implemented, and store/state.

The actual problem is the following: the sub component is using a store,
and shouldupdate.  Whenever the component is rendered, it checks if there is an incoming
rendering from the context.  If that is the case, it skips the
rendering, because we actually only want to be rendered by the store
rendering (otherwise, we may run into issue with inconsistent data (more
recent data from the context, older data in the component).

However, if shouldUpdate is implemented, then the rendering coming from
the context simply does not arrive.

To fix this, we tried to just force these renderings to go through all children,
regardless of their shouldUpdate status. This actually works, but then
shouldUpdate is ignored, which is an issue in Odoo discuss.

Then, after discussing this situation, we noticed that the context/store
system is actually unsafe: the protection given by the check mentioned
above is in fact fundamentally insufficient: there are other perfectly
valid situations where a rendering can be triggered on the component,
which will bypass the check (for example, an explicit call to
this.render() or a rendering initiated by some parent component) and
cause a crash if the component is not properly defensively written.

Therefore, it is currently mandatory for all components using
context/store to be aware of that, and to protect themselves against
such situations. So, in that regard, the check is not really a
protection, it just helps hiding an unsafe situation anyway and we
decided to remove it.

Note that this is a potentially breaking change: components using a
store and some local state will now be rendered twice in some cases...

closes #799
2020-12-14 13:19:36 +01:00
Géry Debongnie 9a87b9a4a0 [IMP] hooks: add some building blocks for hooks
This commit introduces two new hooks: useComponent, and
useEnv.
2020-12-14 11:53:01 +01:00
Géry Debongnie 2a53a9592e [FIX] component: force mounting subcomponents with shouldUpdate
Components can implement shouldUpdate to return false.  In that case,
renderings coming from above should be ignored.

However, if the component was unmounted and is remounted, we actually
need to force a rerendering in that case, so it is mounted, otherwise
the subcomponent is left in unmounted state, which means that rendering
are ignored.

closes #800
2020-12-11 15:19:37 +01:00
Ivan Yelizariev f54b9a4a0c [FIX] properly translate terms surrounded by spaces
This reimplements logic from Odoo v13 [1], i.e. if we have a text that follows
by space e.g. "This database will expire in " [2], then we want get translation
for the term without that space and add the space manually. This way we can
export trimmed terms for translations and don't miss the space, when atranslator
forget to add it at the end of translation

[1] https://github.com/odoo/odoo/blob/26927417e2957acba6fb79446c2520107daa7eea/addons/web/static/src/js/core/qweb.js#L46
[2] https://github.com/odoo/enterprise/blob/ab0e893493f909ec3033e8a1cf6c141ea9375587/web_enterprise/static/src/xml/base.xml#L21

---

opw-2410708
2020-12-03 13:36:17 +01:00
Géry Debongnie d83cfc12ee [IMP] qweb: the t-slot directive is now dynamic
It is useful for some kind of components to be able to use a completely
dynamic slot expression.
2020-10-30 15:31:03 +01:00
Géry Debongnie cb07c99d40 [IMP] owl: add a new mount method 2020-10-30 15:31:03 +01:00
Géry Debongnie 8d2b250fef [FIX] slots: prevent infinite loop in some cases
The reviewer for the commit on named slots inside named slots did not
notice that there was an infinite loop.  Because of his sloppiness, Owl
could block in an infinite loop when a named t-slots was defined inside
a subcomponent, but not as a direct child.
2020-10-23 12:14:46 +02:00
Géry Debongnie a68d7774c6 [FIX] qweb: issue when rendering twice dynamic t-calls
The previous implementation generated an id each time the template was
rendered, instead of just once per new dynamic template found.
2020-10-20 08:02:03 +02:00
Géry Debongnie ed9d820d9e [FIX] tests: fix cause of non determinism
Since commit 7e4baf6, some tests were failing non deterministically. It
seems like the root cause for the problem is that the nextTick method
was sometimes completed too early.

From my understanding of the problem, the nextTick method was correct,
however it is running in a jest test, in node, which simulates the
requestanimationframe behaviour, probably not perfectly.

Switching to an alternate implementation, which swaps the setTimeout and
the requestanimationframe seems to be more solid.

Note that this commit had to introduce the nextFrame method as well,
because the animation tests really seems to want to be in the next
frame, not in a callback executed in the same frame, but at the end.

closes #757
2020-10-19 21:43:49 +02:00
Géry Debongnie 89eae191b1 [FIX] qweb: correctly handle top level t-call and body
Whenever a top level t-call was made with some non empty body, Owl
complained that a template should not have more than one root node.

The reason was that the compilation context for the body of the t-call
directive was the same as the root compilation context, and it already
had a parentNode set.

To fix the issue, this commit simply use the subContext method to create
a different compilation context, which actually makes sense, because the
body of a t-call is really a different situation.  Also, as a bonus, it
slightly improves the code for the t-call directive.

closes #760
2020-10-19 20:51:44 +02:00
Géry Debongnie 3fbc02986c [FIX] qweb: allow string interpolation in t-call
This commit allows the t-call directive to choose a dynamic template.
This is working in QWeb Python, but was not possible in Owl.

closes #709
2020-10-19 16:27:38 +02:00
Géry Debongnie a28ce440dc [REF] qweb: simplify _compile method arguments
Strangely, the _compile method required a CompilationContext whenever it
was compiled as a sub template, but this parent context was actually not
really needed.  I guess that it was the case in the past, but this was
changed at some point.

This commit makes another significant change: the xml element is no
longer mandatory.  It is actually only required for slots (because the
template is not registered to qweb).

Finally, the interface for the whole method has been changed to use an
option object, which makes more sense with 3 optional paremeters.
2020-10-19 16:27:38 +02:00
Géry Debongnie 8e018fbbda [FIX] qweb: do not render comments as text in t-raw
The code converting html to a vnode did not handle comment nodes as
expected.

closes #761
2020-10-19 16:27:14 +02:00
Géry Debongnie cb38d795f9 [FIX] slots: properly handle named t-slots inside named t-slots
Previous code naively handled nested t-set-slots: if a second named
slots was found, it overrode the first.

In this commit, we use a set to make sure that we only use the first
found t-set-slot node. Also, we ignore set-slots defined in a sub
components, because these slots are only relevant to the sub component
itself.

Note that it works as expected because document.querySelectorAll
performs a search depth first, so we will always use the named slots
closer to the parent element, in term of depth.

closes #682
2020-10-09 15:01:25 +02:00
Géry Debongnie 38c7ad9629 [FIX] t-model: support expressions with [ ]
Before this commit, the t-model directive worked well with expressions
such as "state.value", but not with bracketed expression: "state[value]"
(it generated invalid code).

This commit make the t-model smarter by detecting this case, and
properly capturing the base expression and key variable.

closes #694
2020-09-18 14:58:48 +02:00
Géry Debongnie d0c76c5854 [IMP] qweb: add indeterminate to special input properties
Input with type="checkbox" have a special property (indeterminate) to
visually display the fact that the input value is non determinate (in my
chrome browser, the checkbox is then drawn with a simple - inside). It
does not actually modify the value of the input, only the way it is
displayed.

So, with this commit, owl will properly set the property, as expected.

closes #713
2020-09-18 13:43:25 +02:00
Géry Debongnie e032314739 [FIX] qweb: allow t-call on arbitrary html nodes
This is a rarely (if ever) used feature, but according to our qweb
reference implementation, it is possible to use the
t-call directive on an arbitrary html tag, like this:

<div t-call="my.template"/>

It is then interpreted as:

<div><t t-call="my.template"/></div>

So, with this commit, we make sure that the owl qweb implementation
matches that behaviour.

closes #706
2020-09-18 08:39:57 +02:00
Géry Debongnie b2db7f21ed [FIX] observer: does not proxify promises
Promises are kind of special, and do not behave like usual javascript
values.

For this issue, the problem is that when the observer tries to observe a
promise value, the code will crash with an error like this:

Uncaught TypeError: Method Promise.prototype.then called on incompatible receiver [object Object]

Also, note that it does not make much sense to proxify promise methods
anyway, since they are not (supposed) to be modified.

So, with this commit, we simply consider that promises should be treated
like a primitive value: simply ignored when determining if it should be
proxified

Note that I actually believe that putting promises in a useState is not
a good idea in general.

closes #677
2020-09-17 13:51:10 +02:00
Géry Debongnie 7b8ac13d3f [REF] qweb: mostly revert fix with t-call and vars with body
The previous fix (overriding tostring of VDomArray) is actually more
general, and solves the same issue. So, let us simplify the code and
keep the more general solution.

This reverts commit 3bf91afc3f.
2020-09-17 09:44:08 +02:00
Géry Debongnie 06d852fcf9 [FIX] component: allow using vars with body as props
Consider this scenario:

- a variable v (with a body) is defined in a template
- it is then passed to a sub component as a prop
- and now, it is t-esc-ed.

Before this commit, the displayed value was [object object], because the
value actually passed to the sub component was a VDomArray (internal
structure used to represent nodelists)

This issue is actually quite a problem in practice, because values in a
templates are translated, but not in attributes.  Therefore, using a
t-set directive with a body text content is the proper way to have
translated values at runtime.

We override in this commit the method toString of VDomArray to make sure
it is properly displayed.

Note that we considered changing the way props were generated (by trying
to detect VDomArray, then calling vDomToString), but then the value
would not be able to be used in a t-raw.  Also, it is quite elegant to
be able to format the VDomArray only at the end.

closes #670
2020-09-17 09:44:08 +02:00
Géry Debongnie 7e4baf668a [FIX] test: timing issue
Before this commit, we artificially replaced in the tests the
requestAnimationFrame by a setTimeout, to actually increase the speed of
the tests.  However, this is not really a true replacement.  For
example, a real setTimeout can come before or after a real
nextAnimationFrame, depending on when/where it is requested.

Also, this change exposed another problem: the nextTick function did a
setTimeout before a nextanimationframe. This is not a problem when
nextAnimationFrame is replaced by a setTimeout, because then all
expectations holds in owl.  However, it is wrong: to get to the next
animation frame, we need to request an animation frame, and THEN wait
with a setTimeout.

closes #729
2020-09-17 09:18:05 +02:00
Géry Debongnie fe34ba00a6 [FIX] component: properly validate multiple props
Because of a "break" statement instead of "continue", the check for valid
props was stopping as soon as it met an optional props, which kind of
invalidate the whole system.

closes #717
2020-09-17 08:33:18 +02:00
Géry Debongnie e5e7790530 [FIX] qweb: handle input value attribute as a property
Sometimes, HTML is slightly more subtle than what I initially expect.
Rendering some html is simple, we have tags and attributes.  However,
once we add behaviour, then the situation is more complex:

<input value="abc"/>

is an input with an INITIAL value of "abc", but the attribute does not
actually represent the CURRENT value of the input, which may be
different if the user did change it.

This is basically the difference between "attribute" and "property".

So, when rendering html with owl, we sometimes want to actually set
the property (current value), instead of the html attribute.

This commit make sure that this is the case for inputs with the "value"
attribute.

closes #722
2020-09-17 08:32:02 +02:00
Géry Debongnie 3bf91afc3f [FIX] qweb: fix issue variables set in body of t-call
The body of a t-call directive may be used to define private variables
to the sub template call.

However, the code that handles t-call worked like this:

- compile sub template if necessary
- then compile body of t-call to extract variables

This means that the variables defined in the t-call body were not yet
processed and available in the context.  Because of that, when the call
to t-esc is done, there is not internal qweb var, and the code simply
outputs a scope['varname'], which is in our case a VDOMArray, so it is
displayed as [object object]

What this fix does is changing the way t-esc works: if we are in the
context of a sub template, then it assumes that any outside variable may
or may not be a VDomArray, so it needs to check and eventually convert
it to a string, if necessary.

closes #719
2020-09-16 11:39:32 +02:00
Géry Debongnie 2529aa3ef2 [FIX] component: make concurrent renderings more robust
Here is a situation that can happen in some complicated case:

1. a parent component is rendered, which includes some children
2. it is then willPatched
3. the sub components are then mounted/willUnmounted
4. because of complicated business logic, this causes the parent
component to be rerendered (before parent "patched" method is called)
5. owl will internally reset its currentfiber to null (but there is a
pending rendering!)
6. subsequent rendering will ignore pending rendering
7. havoc ensues

This is actually one of the reason why modifying a component state in a
willPatch component is actually not a good idea.  However, the good news
is that this specific situation can be properly handled: we can simply
make sure that we do not reset currentFiber to null if there is a new
pending rendering.

closes #728
2020-09-16 09:21:33 +02:00
Géry Debongnie 8d25bddda4 [FIX] component: subtle issue with unmounted children
Owl has to manage a lot of interesting situations.  One of them is when
a rendering is initiated, which creates a sub component, but then
another rendering starts, which invalidate the previous one, and will
create another sub component.  Since the first sub component was not
ever in the DOM, we cannot rely on the vdom patching process to remove
it, so we have to do it manually.

Sadly, this is actually a very tricky situation, since there are other
subtle situations where the code that remove an unmounted widget could
be executed, in particular when the parent component is unmounted, then
remounted, then modified to trigger yet another rendering.

In this commit, we handle this case more carefully by making sure that
the destroyed subcomponent properly configures its pvnode so the patch
process happens as expected.

joint work with the framework team, and in particular LPE for his work on
finding a testcase!

closes #724, #731
2020-09-15 15:51:30 +02:00
Lucas Perais (lpe) 81af21a025 [FIX] component, fiber: update props with virtual node should not crash
Have a hierarchy of A, B, C components where:

```xml
<div t-name="A">
  <div>
    <B t-key="key1"/>
  </div>
</div>

<t t-name="B">
  <C t-key="key2"/>
</t>

<div t-name="C">
  <div><t t-esc="keys_as_props" /></div>
</div>
```

The subtility of the issues lies in B, which doesn't have its own
concrete DOM element, rather, it borrows it from C.

With the sequence of events:
- change key2
C1 is destroyed and replaced by another instance, and another node.
B1 has its props updated and is patched with the C2's node (CRITICAL)
A1 is patched

- change key1 AND key2
C2 is destroyed
B1 is destroyed
A1 is patched replacing B1 by B2, and their nodes too (which at this point should be C2's to C3's)

Before this commit, at the CRITICAL point, the node representing the component itself
(technically its pvnode) was not updated with the new concrete node provided by B1 patch with C2 node
i.e. it held the previous node still
The second array of steps crashed because at A1 patch, the new B2 node would replace B1, which
was out of the DOM (removed because C1 was destroyed long before),
and therefore without a viable parent to insert B2 node.

After this commit, we update the component's pvnode after the patch which elm had possibly changed
There is no crash anymore for this use case.
2020-09-14 15:17:45 +02:00