Add ESLint rule to prevent Observable-returning method calls in the async pipe (#5933)#5934
Add ESLint rule to prevent Observable-returning method calls in the async pipe (#5933)#5934Aryakoste wants to merge 3 commits into
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lgeggleston
added
improvement
performance / caching
lgeggleston
moved this from 🙋 Needs Reviewers Assigned
to 👀 Under Review
in DSpace 11.0 Release
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Thank you for the PR @Aryakoste! You may have already seen this, but looks like this is failing a few build tests that will need to be addressed. |
| * RecursiveAstVisitor, which correctly covers the full expression AST regardless of what | ||
| * @angular-eslint/template-parser exposes to ESLint's selector engine. | ||
| */ | ||
| class AsyncPipedCallVisitor extends RecursiveAstVisitor { |
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Good catch on those selectors, I wasn't aware of that!
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↑ those CI failures are due to the new lint rule
This rule does not attempt to fix existing offending call sites — per the issue, migrating those (...) is a separate follow-up.
The rule is not auto-fixable, since that migration can't be done mechanically.
It won't be possible to auto-fix, but we'll still need to sort out that "follow up step" within this PR as we did in previous PRs that introduced new configuration or rules.
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Ok will do that |
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@ybnd @lgeggleston I have done the migration of all the files. |
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@Aryakoste : You may have seen this already, but it looks like this PR is failing ~12 unit tests. We'd obviously need those to pass before we can look for additional reviewers. |
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@tdonohue Yeah i have solved those pushing them |
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References
We commonly call a component method directly as the input of the
asyncpipe in templates, e.g.{{ getFoo$() | async }}. Because the method runs as part of template evaluation, Angular re-executes the whole RxJS pipeline (subscribe + unsubscribe) on every change-detection cycle instead of once — a real, recurring perf issue in this codebase (confirmed instances inaudit-table,ePerson-data, andsection-coar-notifycomponents).This PR adds a new
dspace-angular-htmlESLint rule,no-method-call-with-async-pipe, that flags this pattern anywhere it appears in a template — interpolations, bound attributes/events,@if/@for/@switchblocks,@defertriggers,@let, and object/array literals or optional-chaining wrapped around the pipe.lint/src/rules/html/no-method-call-with-async-pipe.tslint/src/rules/html/index.tsand enabled in.eslintrc.jsonnpm run docs:lint(docs/lint/html/index.md,docs/lint/html/rules/no-method-call-with-async-pipe.md)Implementation note
The straightforward approach — an ESLint selector like
BindingPipe[name="async"] > Call— turned out to miss common real-world cases, because@angular-eslint/template-parser's own visitor-keys map doesn't cover every expression AST node type (e.g.SafePropertyRead,LiteralMap), so ESLint's traversal silently stops before reaching calls wrapped in things like(getFoo$() | async)?.lengthor[ngClass]="{x: getFoo$() | async}". To get full, correct coverage, the rule instead walks each template expression with@angular/compiler's ownRecursiveAstVisitor, which handles every AST node type regardless of that gap.This rule does not attempt to fix existing offending call sites — per the issue, migrating those (subscribe in
ngOnInit(), push into aBehaviorSubject,| asyncon that, unsubscribe inngOnDestroy()) is a separate follow-up. The rule is not auto-fixable, since that migration can't be done mechanically.Checklist
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mainbranch of code (unless it is a backport or is fixing an issue specific to an older branch).npm run lintnpm run check-circ-deps)package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.