This commit adds a feature that is useful for determining if an
application is zoneless-ready. The way this works is generally only
useful right now when zoneless is enabled. Some version of this may be useful in
the future as a general configuration option to change detection to make
`checkNoChanges` pass always exhaustive as an opt-in to address #45612.
Because this is an experimental, debug-only feature, it is okay to merge
during the RC period.
PR Close#55663
This commit fixes an error in the looping logic of `ApplicationRef.tick`
when the tick skips straight to render hooks. In this case, if a render
hook makes a state update that requires a view refresh, we would never
actually refresh the view and just loop until we hit the loop limit.
PR Close#55623
This commit ensures we flush animations by calling renderFactory
begin/end in cases where the ApplicationRef._tick happens in a mode that
skips straight to the render hooks.
PR Close#55564
This change ensures that `ApplicationRef.tick` flushes animations by
calling `rendererFactory2.end`. This might not have happened before if
there were no views that needed to be refreshed.
This is also likely to fix a potential regression caused by #53718 even
in zone apps where animations don't get flushed when no views attached
to ApplicationRef are dirty.
PR Close#55132
This commit ensures that manually calling ApplicationRef.tick will
result in any scheduled change detections being canceled. There is no
need for the scheduled one to run because it was manually done by the
`tick` already.
PR Close#55290
This commit adds a configuration option to zone-based change detection
which allows applications to enable/disable the zoneless scheduler.
When the zoneless scheduler is enabled in zone-based applications,
updates that happen outside the Angular zone will still result in a
change detection being scheduled. Previously, Angular change detection
was solely based on the state of the Angular Zone.
PR Close#55252
This change treats all views attached to `ApplicationRef` as `OnPush`,
meaning that they have to be explicitly marked for check in order to be
refreshed when a tick happens. This prevents "accidentally" refreshing
views which have `Default` change detection as a side effect of running
change detection from an unrelated notification.
In addition, this change helps us achieve one of the big goals of the
project: that we can provide a testing experience which gives developers
more confidence that a component is zoneless-compatible. Because
`ComponentFixture` change detection is run through `ApplicationRef`
instead of `ChangeDetectorRef` when zoneless is enabled, this ensures
that the component under test has correctly been marked for check in
order to be updated. Without this, calling
`ComponentFixture.detectChanges` would allow a test to _force_ change
detection on a view when Angular would have otherwise not known that it
needed to be updated. Calling `ComponentFixture.detectChanges` on a component
which is not marked for check will now omit refreshing component view.
PR Close#55099
This change updates the approach to the loop in `ApplicationRef.tick`
for allowing state updates in `afterRender` hooks. It is valid to update
state in render hooks and we need to ensure we refresh views that may be
marked for check in these hooks (this can happen simply as a result of
focusing an element). This change ensures that the behavior of `markForCheck`
with respect to this loop does not change while we are actively running
change detection on a view tree.
This approach also has the benefit of preventing a regression for #18917,
where updating state in animation listeners can cause `ExpressionChanged...Error`
This should be allowed - there is nothing wrong with respect to unidirectional
data flow in this case.
There may be other cases in the future where it is valid to update
state. Rather than wrapping the render hooks and the animation flushing
in something which flips a global state flag, the idea here is that
`markForCheck` is safe and valid in all cases whenever change detection
is not actively running.
PR Close#54900
This commit updates the loop in ApplicationRef.tick to only throw in dev
mode. In addition, it reduces the reruns to 10 from 100 in order to
reduce the impact on production applications that encounter this error.
That is, the loop will bail out much earlier and prevent prolonged
unresponsiveness.
PR Close#54848
This commit updates `ApplicationRef.tick` to use `detectChangesInternal` for root
views rather than go through the `ChangeDetectorRef.detectChanges` API
which refreshes the host view without first looking at whether the view
is `OnPush` and not dirty. The current behavior would hide errors in
`OnPush` components that do not correctly get marked for check and would
break when migrating to zoneless change detection because `markForCheck`
was never called so change detection was never scheduled.
The error would be surprising and blamed on switching to zoneless when in
reality the issue already exists and is a problem with the component not
calling `markForCheck`. However, this error is hidden today because
`ApplicationRef.tick` refresh host bindings unconditionally.
BREAKING CHANGE: `OnPush` views at the root of the application need to
be marked dirty for their host bindings to refresh. Previously, the host
bindings were refreshed for all root views without respecting the
`OnPush` change detection strategy.
PR Close#53718
PR Close#53718
This commit updates `ApplicationRef.tick` to use `detectChangesInternal` for root
views rather than go through the `ChangeDetectorRef.detectChanges` API
which refreshes the host view without first looking at whether the view
is `OnPush` and not dirty. The current behavior would hide errors in
`OnPush` components that do not correctly get marked for check and would
break when migrating to zoneless change detection because `markForCheck`
was never called so change detection was never scheduled.
The error would be surprising and blamed on switching to zoneless when in
reality the issue already exists and is a problem with the component not
calling `markForCheck`. However, this error is hidden today because
`ApplicationRef.tick` refresh host bindings unconditionally.
BREAKING CHANGE: `OnPush` views at the root of the application need to
be marked dirty for their host bindings to refresh. Previously, the host
bindings were refreshed for all root views without respecting the
`OnPush` change detection strategy.
PR Close#53718
When the `ApplicationRef` refreshes attached views, it will continue to
do so while there is still one marked for check after the refresh
completes.
BREAKING CHANGE: When Angular runs change detection, it will continue to
refresh any views attached to `ApplicationRef` that are still marked for
check after one round completes. In rare cases, this can result in infinite
loops when certain patterns continue to mark views for check using
`ChangeDetectorRef.detectChanges`. This will be surfaced as a runtime
error with the `NG0103` code.
PR Close#54734
The current behavior of `autoDetect` in `ComponentFixture` does not
match production very well. It has several flaws that make it an
insufficient change detection mechanism:
* It runs change detection for the component under test _after_ views
attached to the `ApplicationRef`. This can cause real behavior
differences that break in production, because tests can observe view
refreshes in the incorrect order (for example, a dialog refreshing
before the component which opened it).
* Because of the above ordering, render hooks registered during change
detection of the fixture views _will not execute at all_ because
`ApplicationRef.tick` already happen.
* It does not rerun change detection on the view tree if there are more
dirty views to refresh after the render hooks complete.
* It effectively hides/swallows errors from change detection inside the
`onMicrotaskEmpty` subscription by not reporting them to the error
handler. Instead, this error ends up being unhandled in the
subscription and rxjs throws these in a `setTimeout`.
All of the above are problematic but this commit _does not_ fix the
final point. Ideally, we can land this in a future change but this
requires additional internal fixes. In the meantime, we have to juggle
special-case handling of the component fixture views within
`ApplicationRef.tick` using some special events to retain current
behavior and avoid errors from the fixture propagating to the `ErrorHandler`.
breaking note for future when isG3 flag condition is removed for v18:
The `ComponentFixture.autoDetect` feature now executes
change detection for the fixture within `ApplicationRef.tick`. This more
closely matches the behavior of how a component would refresh in
production. The order of component refresh in tests may be slightly
affected as a result, especially when dealing with additional components
attached to the application, such as dialogs. Tests sensitive to this
type of change (such as screenshot tests) may need to be updated.
PR Close#54354
One downside of implicit dependency tracking in `effect()`s is that it's easy
to for downstream code to end up running inside the effect context by accident.
For example, if an effect raises an event (e.g. by `next()`ing a `Subject`), the
subscribers to that `Observable` will run inside the effect's reactive context,
and any signals read within the subscriber will end up as dependencies of the
effect. This is why the `untracked` function is useful, to run certain
operations without incidental signal reads ending up tracked.
However, knowing when this is necessary is non-trivial. For example, injecting
a dependency might cause it to be instantiated, which would run the constructor
in the effect context unless the injection operation is untracked.
Therefore, Angular will automatically drop the reactive context within a number
of framework APIs. This commit addresses these use cases:
* creating and destroying views
* creating and destroying DI injectors
* injecting dependencies
* emitting outputs
Fixes#54548
There are likely other APIs which would benefit from this approach, but this
is a start.
PR Close#54614
This commit ensures that any internal render hooks that cause views to
become dirty again first refresh those dirty views before running user
render hooks. This ensures that user render hooks have the most complete
render state possible and stops them from needlessly executing multiple
times. This is important to maintain the goal of the public render
hooks, which is to provide the safest place to place code that depends
on DOM state, especially in ways that may force a browser paint.
PR Close#54224
ApplicationRef.tick has a loop that will refresh views again that have
an updated signal. This change ensures views marked with the `Dirty`
flag are also considered in this loop, but only inside g3 for now
because this may be considered a breaking change and we need to wait for
v18 to land externally.
PR Close#54572
In some situations, calling `markForCheck` can result in an infinite
loop in seemingly valid scenarios. When a transplanted view is inserted
before its declaration, it gets refreshed in the retry loop of
`detectChanges`. At this point, the `Dirty` flag has been cleared from
all parents. Calling `markForCheck` marks the insertion tree up to the
root `Dirty`. If the declaration is checked again as a result (i.e.
because it has default change detection) and is reachable because its
parent was marked `Dirty`, this can cause an infinite loop. The
declaration is refreshed again, so the insertion is marked for refresh
(again). We enter an infinite loop if the insertion tree always calls
`markForCheck` for some reason (i.e. `{{createReplayObservable() | async}}`).
While the case above does fall into an infinite loop, it also truly is a
problem in the application. While it's not an infinite synchronous loop,
the declaration and insertion are infinitely dirty and will be refreshed
on every change detection round.
Usually `markForCheck` does not have this problem because the `Dirty`
flag is not cleared until the very end of change detection. However, if
the view did not already have the `Dirty` flag set, it is never cleared
because we never entered view refresh. One solution to this problem
could be to clear the `Dirty` flag even after skipping view refresh but
traversing to children.
PR Close#54329
The compileNgModuleFactory dont need to be in the application_ref file (in fact
the whole logic has little to do with ApplicationRef and it is not even called
from the application_ref). Performing this move to avoid circular dependencies
when the new query as signals authoring functions are exported.
PR Close#54103
It was always the intent to have `afterRender` hooks allow updating
state, as long as those state updates specifically mark views for
(re)check. This commit delivers that behavior. Developers can now use
`afterRender` hooks to perform further updates within the same change
detection cycle rather than needing to defer this work to another round
(i.e. `queueMicrotask(() => <<updateState>>)`). This is an important
change to support migrating from the `queueMicrotask`-style deferred
updates, which are not entirely compatible with zoneless or event `NgZone` run
coalescing.
When using a microtask to update state after a render, it
doesn't work with coalescing because the render may not have happened
yet (coalescing and zoneless use `requestAnimationFrame` while the
default for `NgZone` is effectively a microtask-based change detection
scheduler). Second, when using a `microtask` _during_ change detection to defer
updates to the next cycle, this can cause updates to be split across
multiple frames with run coalescing and with zoneless (again, because of
`requestAnimationFrame`/`macrotask` change detection scheduling).
PR Close#54074
This change updates the `checkNoChanges` pass to only run once after
both view refresh and `afterRender` hooks execute rather than both
before and after the hooks. The original motivation was to specifically
ensure that the application was in a "clean state" before running the
`afterRender` hooks and ensure that `afterRender` hooks don't "fix"
`ExpressionChanged...` errors. This, however, adds to the complexity and
cost of running change detection in dev mode. Instead, the
`checkNoChanges` pass runs once we have done all render-related work and
want to ensure that the application state has been synced to the DOM
(without additional changes).
PR Close#54074
Errors during change detection are terminal and we do not generally
attempt to continue processing or recover after one occurs. This helps clean
up the `tick` implementation with respect to running `afterRender` hooks.
PR Close#54074
The `afterRender` hooks currently run after `ApplicationRef.tick` but
also run after any call to `ChangeDetectorRef.detectChanges`. This is
problematic because code which uses `afterRender` cannot expect the
component it's registered from to be rendered when the callback
executes. If there is a call to `ChangeDetectorRef.detectChanges` before
the global change detection, that will cause the hooks to run earlier
than expected.
This behavior is somewhat of a blocker for the zoneless project. There
is plenty of application code that do things like `setTimeout(() =>
doSomethingThatExpectsComponentToBeRendered())`, `NgZone.onStable(() =>
...)` or `ApplicationRef.onStable...`. `ApplicationRef.onStable` is a
should likely work similarly, but all of these are really wanting an API
that is `afterRender` with the requirement that the hook runs after the
global render, not an individual CDRef instance.
This change updates the `afterRender` hooks to only run when
`ApplicationRef.tick` happens.
fixes#52429fixes#53232
PR Close#52455
In order to provide a reasonable experience for Angular without Zones,
we need a mechanism to run change detection when we receive a change
notification. There are several existing APIs today that serve as the
change notification: `ChangeDetectorRef.markForCheck`, signal updates,
event listeners (since they mark the view dirty), and attaching a view to
either the `ApplicationRef` or `ChangeDetectorRef`. These operations
are now paired with a notification to the change detection scheduler.
The concrete implementation for this scheduler is still being designed.
However, this gives us a starting point to partner with teams to
experiment with what that might look like.
PR Close#53499
This commit updates the `ApplicationRef.isStable` implementation to use
a single `Observable` to manage the state. This simplifies the mental
model quite a bit and removes the need for rx operators like
`distinctUntilChanged` and `combineLatest`.
PR Close#53576
When an application does not use zones, it does not need a default value
for the zone stableness token. This will allow zoneless applications to
tree-shake a lot of rxjs operators out of `ApplicationRef`.
Note that at the moment, `provideZoneChangeDetection` is included in all
applications as well as the `TestBed` environment. It is not currently
possible to remove the zone stable code as a result. This will be
possible only when we make zones an opt-in rather than opt-out.
PR Close#53505
The InitialRenderPendingTasks currently attempts to only contribute to
ApplicationRef stableness one time to support SSR. This isn't actually
how the switchMap works in reality. This commit updates
the isStable observable to be more clear that it's always a combination
of the zone stableness and pending tasks.
In addition, this commit renames the service to just be PendingTasks
because it doesn't directly relate to rendering. While the purpose is
to track things that might cause rendering to happen, we don't know if the
tasks will affect rendering at all.
PR Close#53534
The behavior of `ApplicationRef.isStable` changed in 16.1 due to
28c68f709c.
This change added a `share` to the `isStable` observable, which prevents
additional subscribers from getting a value until a new one emits. One
solution to the problem would be `shareReplay(1)`. However, that would
increase the bundle size since we do not use `shareReplay` elsewhere.
Instead, we don't even really need to share the observable.
The `Observable` available in `ApplicationRef.isStable` before the above commit
was the zone stable observable, without a `share`. The new behavior adds
only an additional observable to the stream, `hasPendingTasks` (a `BehaviorSubject`).
The observables in this stream are not expensive to subscribe to. The
only one with side effects is the `isStable` (because it subscribes to
onStable), but that one already has the `share` operator on it.
Omitting the `share` in `ApplicationRef` also means that applications on `zoneless` will not
have to pay the cost of the operator when we make zones optional because
the zone stable observable is the only place we use it.
PR Close#53541
This separates application and platform code into even more files. This now removes
the ciruclar dependency between scheduling and application ref.
PR Close#53371
