[compiler] Validate static components #32683
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React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
[ghstack-poisoned]
josephsavona
added a commit
that referenced
this pull request
Mar 19, 2025
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
ghstack-source-id: 8ab6b44
Pull Request resolved: #32683
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mofeiZ
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| if (error.hasErrors()) { | ||
| throw error; | ||
| } |
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Hmm thoughts on just logging this error instead of throwing? Most of our validations have to do with the memoization feature of the compiler, so throwing makes sense for no-ref-access-in-render, hooks-usage, and no-impure-functions-during-render.
For validation like this pass and ValidateNoJSXInTryStatement though, could we just report diagnostics via the logger without bailing out? In the longer term, we can mark some validation passes as required for memo and some as needing to only run for the eslint plugin
fn.env.logger?.logEvent(<file name>, err);React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
[ghstack-poisoned]
josephsavona
added a commit
that referenced
this pull request
Mar 20, 2025
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
ghstack-source-id: e7408c0
Pull Request resolved: #32683
josephsavona
commented
Mar 20, 2025
| */ | ||
| export function validateStaticComponents( | ||
| fn: HIRFunction, | ||
| ): Result<void, CompilerError> { |
There was a problem hiding this comment.
per feedback i switched to return a Result here. this lets us easily refactor later to throw the error if we want, without rewriting the validation pass itself
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
[ghstack-poisoned]
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
[ghstack-poisoned]
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
[ghstack-poisoned]
josephsavona
added a commit
that referenced
this pull request
Mar 20, 2025
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
```js
function Example() {
const Component = createComponent();
return <Component />;
}
```
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.
ghstack-source-id: e7408c0
Pull Request resolved: #32683
This was referenced Mar 21, 2025
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Stack from ghstack (oldest at bottom):
React uses function identity to determine whether a given JSX expression represents the same type of component and should reconcile (keep state, update props) or replace (teardown state, create a new instance). This PR adds off-by-default validation to check that developers are not dynamically creating components during render.
The check is local and intentionally conservative. We specifically look for the results of call expressions, new expressions, or function expressions that are then used directly (or aliased) as a JSX tag. This allows common sketchy but fine-in-practice cases like passing a reference to a component from a parent as props, but catches very obvious mistakes such as:
We could expand this to catch more cases, but this seems like a reasonable starting point. Note that I tried enabling the validation by default and the only fixtures that error are the new ones added here. I'll also test this internally. What i'm imagining is that we enable this in the linter but not the compiler.