Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Revert "amp-list: Fix Bind.rescan vs. diffing race condition" #33232

Merged
merged 2 commits into from
Mar 15, 2021
Merged

Revert "amp-list: Fix Bind.rescan vs. diffing race condition" #33232

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f41e3be
Revert "amp-list: Fix Bind.rescan vs. diffing race condition (#32650)"
samouri Mar 12, 2021
eea4429
Merge branch 'master' into revert-32650-diffable-race
samouri Mar 12, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
58 changes: 13 additions & 45 deletions extensions/amp-list/0.1/amp-list.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1095,19 +1095,21 @@ export class AmpList extends AMP.BaseElement {

// binding=refresh: Only do render-blocking update after initial render.
if (binding && binding.startsWith('refresh')) {
// Don't bother using bindForDocOrNull() since the Bind service must be available after first mutate.
const afterFirstMutate =
this.bind_ && this.bind_.signals().get('FIRST_MUTATE');
if (afterFirstMutate) {
// Bind service must be available after first mutation, so don't
// wait on the async service getter.
if (this.bind_ && this.bind_.signals().get('FIRST_MUTATE')) {
return updateWith(this.bind_);
} else {
// This must be initial render, so do a non-blocking scan for bindings only.
// [diffable] is a special case that is handled later in render_(), see comment there.
if (!this.element.hasAttribute('diffable')) {
this.scanForBindings_(elements, []);
}

// Don't block render and return synchronously.
// On initial render, do a non-blocking scan and don't update.
Services.bindForDocOrNull(this.element).then((bind) => {
if (bind) {
const evaluate = binding == 'refresh-evaluate';
bind.rescan(elements, [], {
'fast': true,
'update': evaluate ? 'evaluate' : false,
});
}
});
return Promise.resolve(elements);
}
}
Expand All @@ -1122,32 +1124,6 @@ export class AmpList extends AMP.BaseElement {
});
}

/**
* Scans for bindings in `addedElements` and removes bindings in `removedElements`.
* Unlike updateBindings(), does NOT apply bindings or update DOM.
* Should only be used for binding="refresh" or binding="refresh-evaluate".
* @param {!Array<!Element>} addedElements
* @param {!Array<!Element>} removedElements
* @private
*/
scanForBindings_(addedElements, removedElements) {
const binding = this.element.getAttribute('binding');
if (!binding || !binding.startsWith('refresh')) {
return;
}
Services.bindForDocOrNull(this.element).then((bind) => {
if (bind) {
// For binding="refresh-evaluate", we scan for bindings, evaluate+cache expressions, but skip DOM update.
// For binding="refresh", we only scan for bindings.
const update = binding == 'refresh-evaluate' ? 'evaluate' : false;
bind.rescan(addedElements, removedElements, {
'fast': true,
'update': update,
});
}
});
}

/**
* @param {!Array<!Element>} elements
* @param {boolean=} opt_append
Expand All @@ -1164,14 +1140,6 @@ export class AmpList extends AMP.BaseElement {
// TODO:(wg-performance)(#28781) Ensure owners_.scheduleUnlayout() is
// called for diff elements that are removed
this.diff_(container, elements);

// For diffable amp-list, we have to wait until DOM diffing is done here to scan for new bindings
// (vs. asynchronously in updateBindings()), and scan the entire container (vs. just `elements`).
//
// This is because instead of replacing the entire DOM subtree, the diffing process removes
// select children from `elements` and inserts them into the container. This results in a race
// between diff_() and Bind.rescan(), which we avoid by delaying the latter until now.
this.scanForBindings_([container], [container]);
} else {
if (!opt_append) {
this.owners_./*OK*/ scheduleUnlayout(this.element, container);
Expand Down
44 changes: 0 additions & 44 deletions extensions/amp-list/0.1/test/test-amp-list.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1413,50 +1413,6 @@ describes.repeated(
}
);
});

describe('rescan vs. diff race', () => {
async function rescanVsDiffTest() {
env.sandbox.spy(list, 'diff_');
env.sandbox.spy(list, 'render_');

// Diffing is skipped if there's no existing children to diff against.
const oldChild = doc.createElement('p');
oldChild.textContent = 'foo';
list.container_.appendChild(oldChild);

const newChild = doc.createElement('p');
newChild.textContent = 'bar';
// New children must have at least one binding to trigger rescan.
newChild.setAttribute('i-amphtml-binding', '');
const rendered = expectFetchAndRender(DEFAULT_FETCHED_DATA, [
newChild,
]);
await list.layoutCallback().then(() => rendered);
}

it('without diffing, should rescan _before_ render', async () => {
await rescanVsDiffTest();

expect(list.diff_).to.not.have.been.called;
expect(bind.rescan).to.have.been.calledOnce;

// Without diffable, rescan should happen before rendering the new children.
expect(bind.rescan).calledBefore(list.render_);
});

it('with diffing, should rescan _after_ render/diff', async () => {
element.setAttribute('diffable', '');

await rescanVsDiffTest();

expect(list.diff_).to.have.been.calledOnce;
expect(bind.rescan).to.have.been.calledOnce;

// With diffable, rescanning must happen after rendering (diffing) the new children.
expect(bind.rescan).calledAfter(list.render_);
expect(bind.rescan).calledAfter(list.diff_);
});
});
});

describe('binding="no"', () => {
Expand Down