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[compiler] Transitively freezing functions marks values as frozen, not effects #30766

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merged 2 commits into from
Aug 22, 2024
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[compiler] Transitively freezing functions marks values as frozen, not effects #30766

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[compiler] Transitively freezing functions marks values as frozen, no…
josephsavona Aug 21, 2024
517951a
Update on "[compiler] Transitively freezing functions marks values as…
josephsavona Aug 21, 2024
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59 changes: 36 additions & 23 deletions compiler/packages/babel-plugin-react-compiler/src/Inference/InferReferenceEffects.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -453,6 +453,37 @@ class InferenceState {
}
}

freezeValues(values: Set<InstructionValue>, reason: Set<ValueReason>): void {
for (const value of values) {
this.#values.set(value, {
kind: ValueKind.Frozen,
reason,
context: new Set(),
});
if (value.kind === 'FunctionExpression') {
if (
this.#env.config.enablePreserveExistingMemoizationGuarantees ||
this.#env.config.enableTransitivelyFreezeFunctionExpressions
) {
if (value.kind === 'FunctionExpression') {
/*
* We want to freeze the captured values, not mark the operands
* themselves as frozen. There could be mutations that occur
* before the freeze we are processing, and it would be invalid
* to overwrite those mutations as a freeze.
*/
for (const operand of eachInstructionValueOperand(value)) {
const operandValues = this.#variables.get(operand.identifier.id);
if (operandValues !== undefined) {
this.freezeValues(operandValues, reason);
}
}
}
}
}
}
}

reference(
place: Place,
effectKind: Effect,
Expand Down Expand Up @@ -482,29 +513,7 @@ class InferenceState {
reason: reasonSet,
context: new Set(),
};
values.forEach(value => {
this.#values.set(value, {
kind: ValueKind.Frozen,
reason: reasonSet,
context: new Set(),
});

if (
this.#env.config.enablePreserveExistingMemoizationGuarantees ||
this.#env.config.enableTransitivelyFreezeFunctionExpressions
) {
if (value.kind === 'FunctionExpression') {
for (const operand of eachInstructionValueOperand(value)) {
this.referenceAndRecordEffects(
operand,
Effect.Freeze,
ValueReason.Other,
[],
);
}
}
}
});
this.freezeValues(values, reasonSet);
} else {
effect = Effect.Read;
}
Expand Down Expand Up @@ -1241,13 +1250,17 @@ function inferBlock(
case 'ObjectMethod':
case 'FunctionExpression': {
let hasMutableOperand = false;
const mutableOperands: Array<Place> = [];
for (const operand of eachInstructionOperand(instr)) {
state.referenceAndRecordEffects(
operand,
operand.effect === Effect.Unknown ? Effect.Read : operand.effect,
ValueReason.Other,
[],
);
if (isMutableEffect(operand.effect, operand.loc)) {
mutableOperands.push(operand);
}
hasMutableOperand ||= isMutableEffect(operand.effect, operand.loc);

/**
Expand Down
53 changes: 28 additions & 25 deletions ...rc/__tests__/fixtures/compiler/allow-mutate-global-in-effect-fixpoint.expect.md
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Original file line number Diff line number Diff line change
Expand Up @@ -46,54 +46,57 @@ import { useEffect, useState } from "react";
let someGlobal = { value: null };

function Component() {
const $ = _c(6);
const $ = _c(7);
const [state, setState] = useState(someGlobal);

let x = someGlobal;
while (x == null) {
x = someGlobal;
}

const y = x;
let t0;
let t1;
let t2;
if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
t0 = () => {
let x = someGlobal;
while (x == null) {
x = someGlobal;
}

const y = x;
t0 = useEffect;
t1 = () => {
y.value = "hello";
};
t1 = [];
t2 = [];
$[0] = t0;
$[1] = t1;
$[2] = t2;
} else {
t0 = $[0];
t1 = $[1];
t2 = $[2];
}
useEffect(t0, t1);
let t2;
t0(t1, t2);
let t3;
if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
t2 = () => {
let t4;
if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
t3 = () => {
setState(someGlobal.value);
};
t3 = [someGlobal];
$[2] = t2;
t4 = [someGlobal];
$[3] = t3;
$[4] = t4;
} else {
t2 = $[2];
t3 = $[3];
t4 = $[4];
}
useEffect(t2, t3);
useEffect(t3, t4);

const t4 = String(state);
let t5;
if ($[4] !== t4) {
t5 = <div>{t4}</div>;
$[4] = t4;
const t5 = String(state);
let t6;
if ($[5] !== t5) {
t6 = <div>{t5}</div>;
$[5] = t5;
$[6] = t6;
} else {
t5 = $[5];
t6 = $[6];
}
return t5;
return t6;
}

export const FIXTURE_ENTRYPOINT = {
Expand Down
51 changes: 23 additions & 28 deletions .../error.todo-repro-missed-memoization-from-inferred-mutation-in-logger.expect.md
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Original file line number Diff line number Diff line change
Expand Up @@ -8,16 +8,14 @@ import LogEvent from 'LogEvent';
import {useCallback, useMemo} from 'react';

component Component(id) {
const {data} = useFragment();
const items = data.items.edges;
const items = useFragment();

const [prevId, setPrevId] = useState(id);
const [index, setIndex] = useState(0);

const logData = useMemo(() => {
const item = items[index];
return {
key: item.key ?? '',
key: item.key,
};
}, [index, items]);

Expand All @@ -35,7 +33,6 @@ component Component(id) {
);

if (prevId !== id) {
setPrevId(id);
setCurrentIndex(0);
}

Expand All @@ -55,29 +52,27 @@ component Component(id) {
## Error

```
19 |
20 | const setCurrentIndex = useCallback(
> 21 | (index: number) => {
| ^^^^^^^^^^^^^^^^^^^^
> 22 | const object = {
| ^^^^^^^^^^^^^^^^^^^^^^
> 23 | tracking: logData.key,
| ^^^^^^^^^^^^^^^^^^^^^^
> 24 | };
| ^^^^^^^^^^^^^^^^^^^^^^
> 25 | // We infer that this may mutate `object`, which in turn aliases
| ^^^^^^^^^^^^^^^^^^^^^^
> 26 | // data from `logData`, such that `logData` may be mutated.
| ^^^^^^^^^^^^^^^^^^^^^^
> 27 | LogEvent.log(() => object);
| ^^^^^^^^^^^^^^^^^^^^^^
> 28 | setIndex(index);
| ^^^^^^^^^^^^^^^^^^^^^^
> 29 | },
| ^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (21:29)
30 | [index, logData, items]
31 | );
32 |
9 | const [index, setIndex] = useState(0);
10 |
> 11 | const logData = useMemo(() => {
| ^^^^^^^^^^^^^^^
> 12 | const item = items[index];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 13 | return {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 14 | key: item.key,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 15 | };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 16 | }, [index, items]);
| ^^^^^^^^^^^^^^^^^^^^^ CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (11:16)

CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly (28:28)

CannotPreserveMemoization: React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. (19:27)
17 |
18 | const setCurrentIndex = useCallback(
19 | (index: number) => {
```


7 changes: 2 additions & 5 deletions ...fixtures/compiler/error.todo-repro-missed-memoization-from-inferred-mutation-in-logger.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,14 @@ import LogEvent from 'LogEvent';
import {useCallback, useMemo} from 'react';

component Component(id) {
const {data} = useFragment();
const items = data.items.edges;
const items = useFragment();

const [prevId, setPrevId] = useState(id);
const [index, setIndex] = useState(0);

const logData = useMemo(() => {
const item = items[index];
return {
key: item.key ?? '',
key: item.key,
};
}, [index, items]);

Expand All @@ -31,7 +29,6 @@ component Component(id) {
);

if (prevId !== id) {
setPrevId(id);
setCurrentIndex(0);
}

Expand Down