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no-duplicate-constant-values: apply minimum-group-size guard to booleans #50247

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Merged
pelikhan merged 2 commits into from
Aug 4, 2026
+23 −1
Merged

no-duplicate-constant-values: apply minimum-group-size guard to booleans #50247

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12c2a1f
Initial plan
Copilot Aug 4, 2026
5b4a413
Apply minimum-group-size guard to boolean constant duplicates
Copilot Aug 4, 2026
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17 changes: 17 additions & 0 deletions eslint-factory/src/rules/no-duplicate-constant-values.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,8 @@ describe("no-duplicate-constant-values", () => {
`const NOTIFY_TIMEOUT_MS = 10000; const KEEPALIVE_PING_INTERVAL_MS = 10000;`,
`const A_PREFIX_LENGTH = 2; const B_PREFIX_LENGTH = 2;`,
`const DEFAULT_HTTP_TIMEOUT_MS = 15000; const TOOL_CALL_TIMEOUT_BUFFER_MS = 15000; const NOTIFY_TIMEOUT_MS = 10000; const KEEPALIVE_PING_INTERVAL_MS = 10000;`,
`const FIRST_ENABLED = true; const SECOND_ENABLED = true;`,
`const FIRST_ENABLED = false; const SECOND_ENABLED = false;`,
],
invalid: [],
});
Expand Down Expand Up @@ -70,6 +72,21 @@ describe("no-duplicate-constant-values", () => {
});
});

it("requires at least three matching boolean constants before reporting duplicates", () => {
ruleTester.run("no-duplicate-constant-values", noDuplicateConstantValuesRule, {
valid: [`const FIRST_ENABLED = true; const SECOND_ENABLED = true;`],
invalid: [
{
code: `const FIRST_ENABLED = true; const SECOND_ENABLED = true; const THIRD_ENABLED = true;`,
errors: [
{ messageId: "duplicateConstantValue", data: { name: "SECOND_ENABLED", originalName: "FIRST_ENABLED", value: "true" } },
{ messageId: "duplicateConstantValue", data: { name: "THIRD_ENABLED", originalName: "FIRST_ENABLED", value: "true" } },
],
},
],
});
});

it("reports every duplicate after the first declaration", () => {
ruleTester.run("no-duplicate-constant-values", noDuplicateConstantValuesRule, {
valid: [],
Expand Down
7 changes: 6 additions & 1 deletion eslint-factory/src/rules/no-duplicate-constant-values.ts
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Expand Up @@ -8,6 +8,10 @@ interface ConstantDeclaration {
}

const MIN_NUMERIC_DUPLICATE_GROUP_SIZE = 3;
// Booleans only have 2 possible values module-wide, an even smaller space than "small numbers",
// so unrelated constants coincidentally sharing `true`/`false` are at least as likely as the
// numeric case above. Apply the same minimum-group-size guard to avoid false positives.
const MIN_BOOLEAN_DUPLICATE_GROUP_SIZE = 3;

function getStaticValueKey(node: TSESTree.Expression): string | null {
if (node.type === AST_NODE_TYPES.Literal) {
Expand Down Expand Up @@ -79,7 +83,8 @@ export const noDuplicateConstantValuesRule = createRule({
},
"Program:exit"() {
for (const [valueKey, declarations] of constantsByValue) {
const shouldReportDuplicates = declarations.length > 1 && (!valueKey.startsWith("number:") || declarations.length >= MIN_NUMERIC_DUPLICATE_GROUP_SIZE);
const minGroupSize = valueKey.startsWith("number:") ? MIN_NUMERIC_DUPLICATE_GROUP_SIZE : valueKey.startsWith("boolean:") ? MIN_BOOLEAN_DUPLICATE_GROUP_SIZE : 2;
const shouldReportDuplicates = declarations.length >= minGroupSize;
if (!shouldReportDuplicates) continue;

const original = declarations[0];
Expand Down