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Edit: /home/techb158/balavpn.abdallabala.com/node_modules/eslint/lib/rules/preserve-caught-error.js (16269B)
/**
* @fileoverview Rule to preserve caught errors when re-throwing exceptions
* @author Amnish Singh Arora
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Types
//------------------------------------------------------------------------------
/** @typedef {import("estree").Node} ASTNode */
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/*
* This is an indicator of an error cause node, that is too complicated to be detected and fixed.
* Eg, when error options is an `Identifier` or a `SpreadElement`.
*/
const UNKNOWN_CAUSE = Symbol("unknown_cause");
const BUILT_IN_ERROR_TYPES = new Set([
"Error",
"EvalError",
"RangeError",
"ReferenceError",
"SyntaxError",
"TypeError",
"URIError",
"AggregateError",
]);
/**
* Finds and returns information about the `cause` property of an error being thrown.
* @param {ASTNode} throwStatement `ThrowStatement` to be checked.
* @returns {{ value: ASTNode; multipleDefinitions: boolean; } | UNKNOWN_CAUSE | null}
* Information about the `cause` of the error being thrown, such as the value node and
* whether there are multiple definitions of `cause`. `null` if there is no `cause`.
*/
function getErrorCause(throwStatement) {
const throwExpression = throwStatement.argument;
/*
* Determine which argument index holds the options object
* `AggregateError` is a special case as it accepts the `options` object as third argument.
*/
const optionsIndex =
throwExpression.callee.name === "AggregateError" ? 2 : 1;
/*
* Make sure there is no `SpreadElement` at or before the `optionsIndex`
* as this messes up the effective order of arguments and makes it complicated
* to track where the actual error options need to be at
*/
const spreadExpressionIndex = throwExpression.arguments.findIndex(
arg => arg.type === "SpreadElement",
);
if (spreadExpressionIndex >= 0 && spreadExpressionIndex <= optionsIndex) {
return UNKNOWN_CAUSE;
}
const errorOptions = throwExpression.arguments[optionsIndex];
if (errorOptions) {
if (errorOptions.type === "ObjectExpression") {
if (
errorOptions.properties.some(
prop => prop.type === "SpreadElement",
)
) {
/*
* If there is a spread element as part of error options, it is too complicated
* to verify if the cause is used properly and auto-fix.
*/
return UNKNOWN_CAUSE;
}
const causeProperties = errorOptions.properties.filter(
prop => astUtils.getStaticPropertyName(prop) === "cause",
);
const causeProperty = causeProperties.at(-1);
return causeProperty
? {
value: causeProperty.value,
multipleDefinitions: causeProperties.length > 1,
}
: null;
}
// Error options exist, but too complicated to be analyzed/fixed
return UNKNOWN_CAUSE;
}
return null;
}
/**
* Finds and returns the `CatchClause` node, that the `node` is part of.
* @param {ASTNode} node The AST node to be evaluated.
* @returns {ASTNode | null } The closest parent `CatchClause` node, `null` if the `node` is not in a catch block.
*/
function findParentCatch(node) {
let currentNode = node;
while (currentNode && currentNode.type !== "CatchClause") {
if (
[
"FunctionDeclaration",
"FunctionExpression",
"ArrowFunctionExpression",
"StaticBlock",
].includes(currentNode.type)
) {
/*
* Make sure the ThrowStatement is not made inside a function definition or a static block inside a high level catch.
* In such cases, the caught error is not directly related to the Throw.
*
* For example,
* try {
* } catch (error) {
* foo = {
* bar() {
* throw new Error();
* }
* };
* }
*/
return null;
}
currentNode = currentNode.parent;
}
return currentNode;
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../types').Rule.RuleModule} */
module.exports = {
meta: {
type: "suggestion",
defaultOptions: [
{
requireCatchParameter: false,
},
],
docs: {
description:
"Disallow losing originally caught error when re-throwing custom errors",
recommended: false,
url: "https://eslint.org/docs/latest/rules/preserve-caught-error", // URL to the documentation page for this rule
},
/*
* TODO: We should allow passing `customErrorTypes` option once something like `typescript-eslint`'s
* `TypeOrValueSpecifier` is implemented in core Eslint.
* See:
* 1. https://typescript-eslint.io/packages/type-utils/type-or-value-specifier/
* 2. https://github.com/eslint/eslint/pull/19913#discussion_r2192608593
* 3. https://github.com/eslint/eslint/discussions/16540
*/
schema: [
{
type: "object",
properties: {
requireCatchParameter: {
type: "boolean",
description:
"Requires the catch blocks to always have the caught error parameter so it is not discarded.",
},
},
additionalProperties: false,
},
],
messages: {
missingCause:
"There is no `cause` attached to the symptom error being thrown.",
incorrectCause:
"The symptom error is being thrown with an incorrect `cause`.",
includeCause:
"Include the original caught error as the `cause` of the symptom error.",
missingCatchErrorParam:
"The caught error is not accessible because the catch clause lacks the error parameter. Start referencing the caught error using the catch parameter.",
partiallyLostError:
"Re-throws cannot preserve the caught error as a part of it is being lost due to destructuring.",
caughtErrorShadowed:
"The caught error is being attached as `cause`, but is shadowed by a closer scoped redeclaration.",
},
hasSuggestions: true,
},
create(context) {
const sourceCode = context.sourceCode;
const [{ requireCatchParameter }] = context.options;
//----------------------------------------------------------------------
// Helpers
//----------------------------------------------------------------------
/**
* Checks if a `ThrowStatement` is constructing and throwing a new `Error` object.
*
* Covers all the error types on `globalThis` that support `cause` property:
* https://github.com/microsoft/TypeScript/blob/main/src/lib/es2022.error.d.ts
* @param {ASTNode} throwStatement The `ThrowStatement` that needs to be checked.
* @returns {boolean} `true` if a new "Error" is being thrown, else `false`.
*/
function isThrowingNewError(throwStatement) {
return (
(throwStatement.argument.type === "NewExpression" ||
throwStatement.argument.type === "CallExpression") &&
throwStatement.argument.callee.type === "Identifier" &&
BUILT_IN_ERROR_TYPES.has(throwStatement.argument.callee.name) &&
/*
* Make sure the thrown Error is instance is one of the built-in global error types.
* Custom imports could shadow this, which would lead to false positives.
* e.g. import { Error } from "./my-custom-error.js";
* throw Error("Failed to perform error prone operations");
*/
sourceCode.isGlobalReference(throwStatement.argument.callee)
);
}
/**
* Inserts `cause:
` into an inline options object expression.
* @param {RuleFixer} fixer The fixer object.
* @param {ASTNode} optionsNode The options object node.
* @param {string} caughtErrorName The name of the caught error (e.g., "err").
* @returns {Fix} The fix object.
*/
function insertCauseIntoOptions(fixer, optionsNode, caughtErrorName) {
const properties = optionsNode.properties;
if (properties.length === 0) {
// Insert inside empty braces: `{}` → `{ cause: err }`
return fixer.insertTextAfter(
sourceCode.getFirstToken(optionsNode),
`cause: ${caughtErrorName}`,
);
}
const lastProp = properties.at(-1);
return fixer.insertTextAfter(
lastProp,
`, cause: ${caughtErrorName}`,
);
}
//----------------------------------------------------------------------
// Public
//----------------------------------------------------------------------
return {
ThrowStatement(node) {
// Check if the throw is inside a catch block
const parentCatch = findParentCatch(node);
const throwStatement = node;
// Check if a new error is being thrown in a catch block
if (parentCatch && isThrowingNewError(throwStatement)) {
if (
parentCatch.param &&
parentCatch.param.type !== "Identifier"
) {
/*
* When a part of the caught error is being lost at the parameter level, commonly due to destructuring.
* e.g. catch({ message, ...rest })
*/
context.report({
messageId: "partiallyLostError",
node: parentCatch,
});
return;
}
const caughtError =
parentCatch.param?.type === "Identifier"
? parentCatch.param
: null;
// Check if there are throw statements and caught error is being ignored
if (!caughtError) {
if (requireCatchParameter) {
context.report({
node: throwStatement,
messageId: "missingCatchErrorParam",
});
return;
}
return;
}
// Check if there is a cause attached to the new error
const errorCauseInfo = getErrorCause(throwStatement);
if (errorCauseInfo === UNKNOWN_CAUSE) {
// Error options exist, but too complicated to be analyzed/fixed
return;
}
if (errorCauseInfo === null) {
// If there is no `cause` attached to the error being thrown.
context.report({
messageId: "missingCause",
node: throwStatement,
suggest: [
{
messageId: "includeCause",
fix(fixer) {
const throwExpression =
throwStatement.argument;
const args = throwExpression.arguments;
const errorType =
throwExpression.callee.name;
// AggregateError: errors, message, options
if (errorType === "AggregateError") {
const errorsArg = args[0];
const messageArg = args[1];
const optionsArg = args[2];
if (!errorsArg) {
// Case: `throw new AggregateError()` → insert all arguments
const lastToken =
sourceCode.getLastToken(
throwExpression,
);
const lastCalleeToken =
sourceCode.getLastToken(
throwExpression.callee,
);
const parenToken =
sourceCode.getFirstTokenBetween(
lastCalleeToken,
lastToken,
astUtils.isOpeningParenToken,
);
if (parenToken) {
return fixer.insertTextAfter(
parenToken,
`[], "", { cause: ${caughtError.name} }`,
);
}
return fixer.insertTextAfter(
throwExpression.callee,
`([], "", { cause: ${caughtError.name} })`,
);
}
if (!messageArg) {
// Case: `throw new AggregateError([])` → insert message and options
return fixer.insertTextAfter(
errorsArg,
`, "", { cause: ${caughtError.name} }`,
);
}
if (!optionsArg) {
// Case: `throw new AggregateError([], "")` → insert error options only
return fixer.insertTextAfter(
messageArg,
`, { cause: ${caughtError.name} }`,
);
}
if (
optionsArg.type ===
"ObjectExpression"
) {
return insertCauseIntoOptions(
fixer,
optionsArg,
caughtError.name,
);
}
// Complex dynamic options — skip
return null;
}
// Normal Error types
const messageArg = args[0];
const optionsArg = args[1];
if (!messageArg) {
// Case: `throw new Error()` → insert both message and options
const lastToken =
sourceCode.getLastToken(
throwExpression,
);
const lastCalleeToken =
sourceCode.getLastToken(
throwExpression.callee,
);
const parenToken =
sourceCode.getFirstTokenBetween(
lastCalleeToken,
lastToken,
astUtils.isOpeningParenToken,
);
if (parenToken) {
return fixer.insertTextAfter(
parenToken,
`"", { cause: ${caughtError.name} }`,
);
}
return fixer.insertTextAfter(
throwExpression.callee,
`("", { cause: ${caughtError.name} })`,
);
}
if (!optionsArg) {
// Case: `throw new Error("Some message")` → insert only options
return fixer.insertTextAfter(
messageArg,
`, { cause: ${caughtError.name} }`,
);
}
if (
optionsArg.type ===
"ObjectExpression"
) {
return insertCauseIntoOptions(
fixer,
optionsArg,
caughtError.name,
);
}
return null; // Identifier or spread — do not fix
},
},
],
});
// We don't need to check further
return;
}
const { value: thrownErrorCause } = errorCauseInfo;
// If there is an attached cause, verify that it matches the caught error
if (
!(
thrownErrorCause.type === "Identifier" &&
thrownErrorCause.name === caughtError.name
)
) {
const suggest = errorCauseInfo.multipleDefinitions
? null // If there are multiple `cause` definitions, a suggestion could be confusing.
: [
{
messageId: "includeCause",
fix(fixer) {
/*
* In case `cause` is attached using object property shorthand or as a method or accessor.
* e.g. throw Error("fail", { cause });
* throw Error("fail", { cause() { doSomething(); } });
* throw Error("fail", { get cause() { return error; } });
*/
if (
thrownErrorCause.parent
.method ||
thrownErrorCause.parent
.shorthand ||
thrownErrorCause.parent.kind !==
"init"
) {
return fixer.replaceText(
thrownErrorCause.parent,
`cause: ${caughtError.name}`,
);
}
return fixer.replaceText(
thrownErrorCause,
caughtError.name,
);
},
},
];
context.report({
messageId: "incorrectCause",
node: thrownErrorCause,
suggest,
});
return;
}
/*
* If the attached cause matches the identifier name of the caught error,
* make sure it is not being shadowed by a closer scoped redeclaration.
*
* e.g. try {
* doSomething();
* } catch (error) {
* if (whatever) {
* const error = anotherError;
* throw new Error("Something went wrong");
* }
* }
*/
let scope = sourceCode.getScope(throwStatement);
do {
const variable = scope.set.get(caughtError.name);
if (variable) {
break;
}
scope = scope.upper;
} while (scope);
if (scope?.block !== parentCatch) {
// Caught error is being shadowed
context.report({
messageId: "caughtErrorShadowed",
node: throwStatement,
});
}
}
},
};
},
};