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eslint-factory: broaden no-unsafe-catch-error-property to flag .status, .cause, .name #42239

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pelikhan merged 2 commits into from
Jun 29, 2026
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eslint-factory: broaden no-unsafe-catch-error-property to flag .status, .cause, .name #42239

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Copilot Jun 29, 2026
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eslint-factory: broaden no-unsafe-catch-error-property to status/caus…
Copilot Jun 29, 2026
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90 changes: 90 additions & 0 deletions eslint-factory/src/rules/no-unsafe-catch-error-property.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -342,6 +342,96 @@ try {
});
});

it("valid: typeof err === 'object' guard suppresses all warnings in the catch block", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [
`try { f(); } catch (err) { if (typeof err === 'object') { console.log(err.status); } }`,
`try { f(); } catch (err) { if (typeof err === 'object' && err !== null) { console.log(err.status); } }`,
`try { f(); } catch (err) { if ('object' === typeof err) { console.log(err.status); } }`,
],
invalid: [],
});
});

it("invalid: err.status without guard is flagged", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `try { f(); } catch (err) { if (err.status === 404) { } }`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "status", errorVar: "err" },
suggestions: [
{
messageId: "wrapWithInstanceof",
data: { errorVar: "err", prop: "status" },
output: `try { f(); } catch (err) { if ((err instanceof Error ? err.status : undefined) === 404) { } }`,
Comment on lines +368 to +370
},
],
},
],
},
],
});
});

it("invalid: err.cause without guard is flagged", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `try { f(); } catch (err) { console.log(err.cause); }`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "cause", errorVar: "err" },
suggestions: [
{
messageId: "wrapWithInstanceof",
data: { errorVar: "err", prop: "cause" },
output: `try { f(); } catch (err) { console.log((err instanceof Error ? err.cause : undefined)); }`,
},
],
},
],
},
],
});
});

it("invalid: err.name without guard is flagged", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `try { f(); } catch (err) { console.log(err.name); }`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "name", errorVar: "err" },
suggestions: [
{
messageId: "wrapWithInstanceof",
data: { errorVar: "err", prop: "name" },
output: `try { f(); } catch (err) { console.log((err instanceof Error ? err.name : undefined)); }`,
},
],
},
],
},
],
});
});

it("valid: typeof err === 'object' guard suppresses .status access (mirrors real call sites)", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [`try { f(); } catch (err) { if (typeof err === 'object' && err.status === 404) { } }`],
invalid: [],
});
});

it("valid: nested try/catch — inner guard does not affect the outer catch block", () => {
cjsRuleTester.run("no-unsafe-catch-error-property", noUnsafeCatchErrorPropertyRule, {
valid: [],
Expand Down
35 changes: 29 additions & 6 deletions eslint-factory/src/rules/no-unsafe-catch-error-property.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ import { AST_NODE_TYPES, ESLintUtils, TSESTree } from "@typescript-eslint/utils"

const createRule = ESLintUtils.RuleCreator(name => `https://github.com/github/gh-aw/tree/main/eslint-factory#${name}`);

const UNSAFE_PROPERTIES = new Set(["message", "stack", "code"]);
const UNSAFE_PROPERTIES = new Set(["message", "stack", "code", "status", "cause", "name"]);

interface CatchFrame {
varName: string;
Expand All @@ -16,7 +16,7 @@ export const noUnsafeCatchErrorPropertyRule = createRule({
type: "problem",
hasSuggestions: true,
docs: {
description: "Disallow direct access to .message, .stack, or .code on a caught error variable without a getErrorMessage guard",
description: "Disallow direct access to .message, .stack, .code, .status, .cause, or .name on a caught error variable without a getErrorMessage guard",
},
schema: [],
messages: {
Expand Down Expand Up @@ -90,18 +90,41 @@ export const noUnsafeCatchErrorPropertyRule = createRule({
},

// Detect catchVar instanceof Error — also accepted as a safe guard
// Detect typeof catchVar === 'object' — also accepted as a safe guard
BinaryExpression(node) {
if (catchStack.length === 0) return;
const top = catchStack[catchStack.length - 1];
if (!top || top.hasGuard || !top.varName) return;

if (node.operator === "instanceof" && node.left.type === AST_NODE_TYPES.Identifier && node.left.name === top.varName) {
top.hasGuard = true;
return;
}

// typeof varName === 'object' or 'object' === typeof varName
if (node.operator === "===") {
const { left, right } = node;
const isTypeofObject =
(left.type === AST_NODE_TYPES.UnaryExpression &&
Comment on lines +104 to +108
left.operator === "typeof" &&
left.argument.type === AST_NODE_TYPES.Identifier &&
left.argument.name === top.varName &&
right.type === AST_NODE_TYPES.Literal &&
right.value === "object") ||
(right.type === AST_NODE_TYPES.UnaryExpression &&
right.operator === "typeof" &&
right.argument.type === AST_NODE_TYPES.Identifier &&
right.argument.name === top.varName &&
left.type === AST_NODE_TYPES.Literal &&
left.value === "object");
if (isTypeofObject) {
top.hasGuard = true;
}
}
},

// Collect catchVar.message / catchVar.stack / catchVar.code accesses
// Also detects computed string-literal access: catchVar["message"], catchVar["stack"], catchVar["code"]
// Collect catchVar.message / catchVar.stack / catchVar.code / catchVar.status / catchVar.cause / catchVar.name accesses
// Also detects computed string-literal access: catchVar["message"], catchVar["status"], etc.
MemberExpression(node) {
if (catchStack.length === 0) return;
const top = catchStack[catchStack.length - 1];
Expand All @@ -112,13 +135,13 @@ export const noUnsafeCatchErrorPropertyRule = createRule({

if (obj.type !== AST_NODE_TYPES.Identifier || obj.name !== top.varName) return;

// Non-computed dot access: err.message / err.stack / err.code
// Non-computed dot access: err.message / err.stack / err.code / err.status / err.cause / err.name
if (!node.computed && prop.type === AST_NODE_TYPES.Identifier && UNSAFE_PROPERTIES.has(prop.name)) {
top.unsafeNodes.push({ node, prop: prop.name });
return;
}

// Computed string-literal access: err["message"] / err["stack"] / err["code"]
// Computed string-literal access: err["message"] / err["stack"] / err["status"] / etc.
// Dynamic access (err[prop]) is kept out of scope intentionally.
if (node.computed && prop.type === AST_NODE_TYPES.Literal && typeof prop.value === "string" && UNSAFE_PROPERTIES.has(prop.value)) {
top.unsafeNodes.push({ node, prop: prop.value });
Expand Down
58 changes: 58 additions & 0 deletions eslint-factory/src/rules/no-unsafe-promise-catch-error-property.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,64 @@ describe("no-unsafe-promise-catch-error-property", () => {
});
});

it("valid: typeof err === 'object' guard suppresses warnings in .catch() callback", () => {
cjsRuleTester.run("no-unsafe-promise-catch-error-property", noUnsafePromiseCatchErrorPropertyRule, {
valid: [`promise.catch(err => { if (typeof err === 'object') { console.log(err.status); } });`, `promise.catch(err => { if ('object' === typeof err) { console.log(err.status); } });`],
invalid: [],
});
});

it("invalid: err.status without guard is flagged in .catch() callback", () => {
cjsRuleTester.run("no-unsafe-promise-catch-error-property", noUnsafePromiseCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `promise.catch(err => { if (err.status === 404) { } });`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "status", errorVar: "err" },
},
],
},
],
});
});

it("invalid: err.cause without guard is flagged in .catch() callback", () => {
cjsRuleTester.run("no-unsafe-promise-catch-error-property", noUnsafePromiseCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `promise.catch(err => { console.log(err.cause); });`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "cause", errorVar: "err" },
},
],
},
],
});
});

it("invalid: err.name without guard is flagged in .catch() callback", () => {
cjsRuleTester.run("no-unsafe-promise-catch-error-property", noUnsafePromiseCatchErrorPropertyRule, {
valid: [],
invalid: [
{
code: `promise.catch(err => { console.log(err.name); });`,
errors: [
{
messageId: "unsafeProperty",
data: { prop: "name", errorVar: "err" },
},
],
},
],
});
});

it("invalid: nested .catch() callbacks are checked independently", () => {
cjsRuleTester.run("no-unsafe-promise-catch-error-property", noUnsafePromiseCatchErrorPropertyRule, {
valid: [],
Expand Down
29 changes: 26 additions & 3 deletions eslint-factory/src/rules/no-unsafe-promise-catch-error-property.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ import { AST_NODE_TYPES, ESLintUtils, TSESTree } from "@typescript-eslint/utils"

const createRule = ESLintUtils.RuleCreator(name => `https://github.com/github/gh-aw/tree/main/eslint-factory#${name}`);

const UNSAFE_PROPERTIES = new Set(["message", "stack", "code"]);
const UNSAFE_PROPERTIES = new Set(["message", "stack", "code", "status", "cause", "name"]);

interface CatchFrame {
varName: string;
Expand All @@ -25,7 +25,7 @@ export const noUnsafePromiseCatchErrorPropertyRule = createRule({
type: "problem",
hasSuggestions: true,
docs: {
description: "Disallow direct access to .message, .stack, or .code on a promise .catch() callback parameter without a getErrorMessage guard",
description: "Disallow direct access to .message, .stack, .code, .status, .cause, or .name on a promise .catch() callback parameter without a getErrorMessage guard",
},
schema: [],
messages: {
Expand Down Expand Up @@ -101,17 +101,40 @@ export const noUnsafePromiseCatchErrorPropertyRule = createRule({
},

// Detect catchVar instanceof Error — also accepted as a safe guard
// Detect typeof catchVar === 'object' — also accepted as a safe guard
BinaryExpression(node) {
if (stack.length === 0) return;
const top = stack[stack.length - 1];
if (!top || top.hasGuard || !top.varName) return;

if (node.operator === "instanceof" && node.left.type === AST_NODE_TYPES.Identifier && node.left.name === top.varName) {
top.hasGuard = true;
return;
}

// typeof varName === 'object' or 'object' === typeof varName
if (node.operator === "===") {
const { left, right } = node;
const isTypeofObject =
(left.type === AST_NODE_TYPES.UnaryExpression &&
Comment on lines +115 to +119
left.operator === "typeof" &&
left.argument.type === AST_NODE_TYPES.Identifier &&
left.argument.name === top.varName &&
right.type === AST_NODE_TYPES.Literal &&
right.value === "object") ||
(right.type === AST_NODE_TYPES.UnaryExpression &&
right.operator === "typeof" &&
right.argument.type === AST_NODE_TYPES.Identifier &&
right.argument.name === top.varName &&
left.type === AST_NODE_TYPES.Literal &&
left.value === "object");
if (isTypeofObject) {
top.hasGuard = true;
}
}
},

// Collect catchVar.message / catchVar.stack / catchVar.code accesses
// Collect catchVar.message / catchVar.stack / catchVar.code / catchVar.status / catchVar.cause / catchVar.name accesses
MemberExpression(node) {
if (stack.length === 0) return;
const top = stack[stack.length - 1];
Expand Down
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