angular-docs-cn/packages
JiaLiPassion 4a8d5ae970 fix(core): markDirty() should only mark flags when really scheduling tick. (#39316)
Close #39296

Fix an issue that `markDirty()` will not trigger change detection.

The case is for example we have the following component.

```
export class AppComponent implements OnInit {
  constructor(private router: Router) {}

  ngOnInit() {
    this.router.events
      .pipe(filter((e) => e instanceof NavigationEnd))
      .subscribe(() => ɵmarkDirty(this));
  }
}

export class CounterComponent implements OnInit, OnDestroy {
  ngOnInit() {
    this.countSubject.pipe(takeUntil(this.destroy)).subscribe((count) => {
      this.count = count;
      ɵmarkDirty(this);
    });
  }
```

Then the app navigate from `AppComponent` to `CounterComponent`,
so there are 2 `markDirty()` call at in a row.

The `1st` call is from `AppComponent` when router changed, the
`2nd` call is from `CounterComponent.ngOnInit()`.

And the `markDirty()->scheduleTick()` code look like this

```
function scheduleTick(rootContext, flags) {
    const nothingScheduled = rootContext.flags === 0 /* Empty */;
    rootContext.flags |= flags;
    if (nothingScheduled && rootContext.clean == _CLEAN_PROMISE) {
      rootContext.schedule(() => {
	...
        if (rootContext.flags & RootContextFlags.DetectChanges)
          rootContext.flags &= ~RootContextFlags.DetectChanges;
          tickContext();

        rootContext.clean = _CLEAN_PROMISE;
        ...
      });
```

So in this case, the `1st` markDirty() will
1. set rootContext.flags = 1
2. before `tickContext()`, reset rootContext.flags = 0
3. inside `tickContext()`, it will call `CounterComponent.ngOnint()`,
   so the `2nd` markDirty() is called.
4. and the `2nd` scheduleTick is called, `nothingScheduled` is true,
   but rootContext.clean is not `_CLEAN_PROMISE` yet, since the `1st` markDirty tick
   is still running.
5. So nowhere will reset the `rootContext.flags`.
6. then in the future, any other `markDirty()` call will not trigger the tick, since
   `nothingScheduled` is always false.

So `nothingScheduled` means no tick is scheduled, `rootContext.clean === _CLEAN_PROMISE`
means no tick is running.
So we should set the flags to `rootContext` only when `no tick is scheudled or running`.

PR Close #39316
2020-10-29 16:07:10 -07:00
..
animations docs: remove IE10 references from comments in the code (#39090) 2020-10-13 15:51:49 -07:00
bazel fix(bazel): only providing stamping information if the --stamp flag is used (#39392) 2020-10-23 15:18:14 -07:00
benchpress build: add wombot proxy for publish config for @angular/benchpress (#37752) 2020-06-25 17:08:18 -07:00
common fix(common): update locales using new CLDR data (#39343) 2020-10-20 13:22:37 -07:00
compiler feat(compiler): recover expression parsing in more malformed pipe cases (#39437) 2020-10-29 12:38:40 -07:00
compiler-cli docs: rename `ng xi18n` to `ng extract-i18n` (#39337) 2020-10-28 14:42:27 -07:00
core fix(core): markDirty() should only mark flags when really scheduling tick. (#39316) 2020-10-29 16:07:10 -07:00
docs docs(di): fix typo in advanced di doc (#36634) 2020-05-01 09:50:28 -07:00
elements refactor(elements): simplify code after IE<11 support removal (#39265) 2020-10-14 14:11:22 -07:00
examples docs: remove explicit boolean type in examples as TS infers it automatically (#39081) 2020-10-06 08:39:01 -07:00
forms docs(forms): update ngModel documentation (#39481) 2020-10-29 11:18:54 -07:00
language-service fix(compiler): do not throw away render3 AST on errors (#39413) 2020-10-27 13:37:19 -07:00
localize fix(localize): render placeholder types in extracted XLIFF files (#39398) 2020-10-27 10:42:15 -07:00
misc/angular-in-memory-web-api feat(core): update reference and doc to change `async` to `waitAsync`. (#37583) 2020-08-03 12:54:13 -07:00
platform-browser fix(core): Store ICU state in `LView` rather than in `TView` (#39233) 2020-10-21 18:33:00 -07:00
platform-browser-dynamic feat(core): update reference and doc to change `async` to `waitAsync`. (#37583) 2020-08-03 12:54:13 -07:00
platform-server fix(platform-server): Resolve absolute URL from baseUrl (#39334) 2020-10-21 09:41:58 -07:00
private/testing build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
router docs(router): Fix ActivationEnd link (#39469) 2020-10-28 11:06:04 -07:00
service-worker feat(service-worker): add the option to prefer network for navigation requests (#38565) 2020-09-22 09:29:20 -07:00
upgrade docs: remove IE10 references from comments in the code (#39090) 2020-10-13 15:51:49 -07:00
zone.js release: cut the zone.js-0.11.3 release (#39440) 2020-10-29 15:40:29 -07:00
BUILD.bazel build: replace @types/trusted-types dep with minimal type defs (#39211) 2020-10-15 09:08:00 -07:00
README.md docs: add doc reference to npm package readme (#33911) 2019-11-20 14:46:23 -08:00
circular-deps-test.conf.js fix(platform-webworker): remove platform-webworker and platform-webworker-dynamic (#38846) 2020-09-30 09:13:59 -04:00
empty.ts build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
goog.d.ts build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
license-banner.txt build: bump year (#34651) 2020-01-13 07:21:43 -08:00
system.d.ts build: update license headers to reference Google LLC (#37205) 2020-05-26 14:26:58 -04:00
tsconfig-build-no-strict.json refactor(core): ensure compatibility with typescript strict flag (#30993) 2019-07-18 14:21:25 -07:00
tsconfig-build.json refactor(core): ensure compatibility with typescript strict flag (#30993) 2019-07-18 14:21:25 -07:00
tsconfig-test.json refactor: fix typescript strict flag failures in all tests (#30993) 2019-07-18 14:21:26 -07:00
tsconfig.json fix(platform-webworker): remove platform-webworker and platform-webworker-dynamic (#38846) 2020-09-30 09:13:59 -04:00
types.d.ts build: replace @types/trusted-types dep with minimal type defs (#39211) 2020-10-15 09:08:00 -07:00

README.md

Angular

The sources for this package are in the main Angular repo. Please file issues and pull requests against that repo.

Usage information and reference details can be found in Angular documentation.

License: MIT