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Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and extra (constrained) object keys #10627

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kachkaev opened this issue Jan 7, 2025 · 1 comment · Fixed by #10644
Closed
4 tasks done

Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and extra (constrained) object keys #10627

kachkaev opened this issue Jan 7, 2025 · 1 comment · Fixed by #10644
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accepting prs Go ahead, send a pull request that resolves this issue bug Something isn't working locked due to age Please open a new issue if you'd like to say more. See https://typescript-eslint.io/contributing. package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin

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@kachkaev
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kachkaev commented Jan 7, 2025 •
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Before You File a Bug Report Please Confirm You Have Done The Following...

  • I have tried restarting my IDE and the issue persists.
  • I have updated to the latest version of the packages.
  • I have searched for related issues and found none that matched my issue.
  • I have read the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.7.2&fileType=.ts&code=C4TwDgpgBAogHsATgQwNIRFAvFABhBFAEgG8BnJASwDsBzAX1wG4AoF0SKAZSQFcBjYL0QQA6pWAALeEmRlsUEiyhQAZgHt1ALigVENWqxUAjZIh3HNAGwjJqRqAG0Cs9CB0yUbgLo7qvAFtjCERWejZ%2BdWoKXT5BYTEJaUI5HR5EASERcSlPOQUlFQ1tKAAiSQgrK3VSgBplKFNzNWQrMgh6lRcUAEFjfh0AFgAmTqhu5AARCFUh0ZZwlkjo9RsAOmraAAo9TISc5NkyNeKASiWoslWIDfVt3fjspLzjpvOLlfXNnbisxNyUscJn1%2BOdllcvncfhlHv9DiggSlpqp3uDrrd7r99s9AY5SsD%2BqVvGDLujvg8-gcXniJsiiacgA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6AEwHs6nuBDfJU5N0URNGidokcGAC%2BIOUA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkRsACprIlngJ4CC006JJAMWbwAkkQAm6AB4BlZAHMiAQzwBXTOgpg8mVenBgAviENA&tokens=false

Repro Code

type ExtraKey = `extra${string}`;

type StructureWithExtras = {
  foo: string;
  bar: boolean;
  [extraKey: ExtraKey]: number;
}

const structureWithExtras: StructureWithExtras = {
  foo: "hello",
  bar: false,
  extraAbc: 42,
  extraDef: 42,
}

console.log(structureWithExtras.foo)
console.log(structureWithExtras.bar)

console.log(structureWithExtras.extraAbc)
console.log(structureWithExtras.extraDef)

console.log(structureWithExtras["extraAbc"])
console.log(structureWithExtras["extraDef"])

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/dot-notation": "error",
  },
};

tsconfig

{
  "compilerOptions": {
    "noPropertyAccessFromIndexSignature": true
  }
}

Expected Result

I expected structureWithExtras["extraAbc"] to not produce ["extraAbc"] is better written in dot notation

Actual Result

  • structureWithExtras.extraAbc is not liked by tsc
  • structureWithExtras["extraAbc"] is not liked by @typescript-eslint/dot-notation

Additional Info

Just using Record<ExtraKey, number> produces the same deadlock (Playground):

type ExtraKey = `extra${string}`;

type StructureWithJustExtras = Record<ExtraKey, number>;

const structureWithJustExtras: StructureWithJustExtras = {
  extraAbc: 42,
  extraDef: 42,
};

console.log(structureWithJustExtras.extraAbc);
console.log(structureWithJustExtras.extraDef);

console.log(structureWithJustExtras["extraAbc"]);
console.log(structureWithJustExtras["extraDef"]);

Replacing Record<ExtraKey, number> with Record<string, number> helps (Playground):

type StructureWithStringKeys = Record<string, number>;

const structureWithStringKeys: StructureWithStringKeys = {
  extraAbc: 42,
  extraDef: 42,
};

console.log(structureWithStringKeys.extraAbc);
console.log(structureWithStringKeys.extraDef);

console.log(structureWithStringKeys["extraAbc"]);
console.log(structureWithStringKeys["extraDef"]);

However, using Record<string, number> would not be possible in the original example where number value is used alongside string and boolean.
@kachkaev kachkaev added bug Something isn't working package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin triage Waiting for team members to take a look labels Jan 7, 2025
@kachkaev kachkaev changed the title Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and extra object keys Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and constrained object keys Jan 7, 2025
@kachkaev kachkaev changed the title Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and constrained object keys Bug: [dot-notation] Conflict between noPropertyAccessFromIndexSignature and extra (constrained) object keys Jan 7, 2025
@bradzacher
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the bug here is due to [extrakey: ExtraKey].
TS's getStringIndexType() method does not treat this indexer as a string indexer and so the rule doesn't see the indexer at all -- hence it reports.

This seems like a bug / limitation in TS's API?
We might have to change strategy to inspect the node's indexInfos and look for indexers with keyType.flags & TypeFlags.StringLike?

@bradzacher bradzacher added accepting prs Go ahead, send a pull request that resolves this issue and removed triage Waiting for team members to take a look labels Jan 7, 2025
@yeonjuan yeonjuan mentioned this issue Jan 13, 2025
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@github-actions github-actions bot added the locked due to age Please open a new issue if you'd like to say more. See https://typescript-eslint.io/contributing. label Feb 11, 2025
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accepting prs Go ahead, send a pull request that resolves this issue bug Something isn't working locked due to age Please open a new issue if you'd like to say more. See https://typescript-eslint.io/contributing. package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin
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