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/**
* @fileoverview A helper that translates context.report() calls from the rule API into generic problem objects
* @author Teddy Katz
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const assert = require("assert");
const ruleFixer = require("./rule-fixer");
const interpolate = require("./interpolate");
//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------
/**
* An error message description
* @typedef {Object} MessageDescriptor
* @property {ASTNode} [node] The reported node
* @property {Location} loc The location of the problem.
* @property {string} message The problem message.
* @property {Object} [data] Optional data to use to fill in placeholders in the
* message.
* @property {Function} [fix] The function to call that creates a fix command.
* @property {Array<{desc?: string, messageId?: string, fix: Function}>} suggest Suggestion descriptions and functions to create a the associated fixes.
*/
/**
* Information about the report
* @typedef {Object} ReportInfo
* @property {string} ruleId The rule ID
* @property {(0|1|2)} severity Severity of the error
* @property {(string|undefined)} message The message
* @property {(string|undefined)} [messageId] The message ID
* @property {number} line The line number
* @property {number} column The column number
* @property {(number|undefined)} [endLine] The ending line number
* @property {(number|undefined)} [endColumn] The ending column number
* @property {(string|null)} nodeType Type of node
* @property {string} source Source text
* @property {({text: string, range: (number[]|null)}|null)} [fix] The fix object
* @property {Array<{text: string, range: (number[]|null)}|null>} [suggestions] Suggestion info
*/
//------------------------------------------------------------------------------
// Module Definition
//------------------------------------------------------------------------------
/**
* Translates a multi-argument context.report() call into a single object argument call
* @param {...*} args A list of arguments passed to `context.report`
* @returns {MessageDescriptor} A normalized object containing report information
*/
function normalizeMultiArgReportCall(...args) {
// If there is one argument, it is considered to be a new-style call already.
if (args.length === 1) {
// Shallow clone the object to avoid surprises if reusing the descriptor
return Object.assign({}, args[0]);
}
// If the second argument is a string, the arguments are interpreted as [node, message, data, fix].
if (typeof args[1] === "string") {
return {
node: args[0],
message: args[1],
data: args[2],
fix: args[3]
};
}
// Otherwise, the arguments are interpreted as [node, loc, message, data, fix].
return {
node: args[0],
loc: args[1],
message: args[2],
data: args[3],
fix: args[4]
};
}
/**
* Asserts that either a loc or a node was provided, and the node is valid if it was provided.
* @param {MessageDescriptor} descriptor A descriptor to validate
* @returns {void}
* @throws AssertionError if neither a node nor a loc was provided, or if the node is not an object
*/
function assertValidNodeInfo(descriptor) {
if (descriptor.node) {
assert(typeof descriptor.node === "object", "Node must be an object");
} else {
assert(descriptor.loc, "Node must be provided when reporting error if location is not provided");
}
}
/**
* Normalizes a MessageDescriptor to always have a `loc` with `start` and `end` properties
* @param {MessageDescriptor} descriptor A descriptor for the report from a rule.
* @returns {{start: Location, end: (Location|null)}} An updated location that infers the `start` and `end` properties
* from the `node` of the original descriptor, or infers the `start` from the `loc` of the original descriptor.
*/
function normalizeReportLoc(descriptor) {
if (descriptor.loc) {
if (descriptor.loc.start) {
return descriptor.loc;
}
return { start: descriptor.loc, end: null };
}
return descriptor.node.loc;
}
/**
* Check that a fix has a valid range.
* @param {Fix|null} fix The fix to validate.
* @returns {void}
*/
function assertValidFix(fix) {
if (fix) {
assert(fix.range && typeof fix.range[0] === "number" && typeof fix.range[1] === "number", `Fix has invalid range: ${JSON.stringify(fix, null, 2)}`);
}
}
/**
* Compares items in a fixes array by range.
* @param {Fix} a The first message.
* @param {Fix} b The second message.
* @returns {int} -1 if a comes before b, 1 if a comes after b, 0 if equal.
* @private
*/
function compareFixesByRange(a, b) {
return a.range[0] - b.range[0] || a.range[1] - b.range[1];
}
/**
* Merges the given fixes array into one.
* @param {Fix[]} fixes The fixes to merge.
* @param {SourceCode} sourceCode The source code object to get the text between fixes.
* @returns {{text: string, range: number[]}} The merged fixes
*/
function mergeFixes(fixes, sourceCode) {
for (const fix of fixes) {
assertValidFix(fix);
}
if (fixes.length === 0) {
return null;
}
if (fixes.length === 1) {
return fixes[0];
}
fixes.sort(compareFixesByRange);
const originalText = sourceCode.text;
const start = fixes[0].range[0];
const end = fixes[fixes.length - 1].range[1];
let text = "";
let lastPos = Number.MIN_SAFE_INTEGER;
for (const fix of fixes) {
assert(fix.range[0] >= lastPos, "Fix objects must not be overlapped in a report.");
if (fix.range[0] >= 0) {
text += originalText.slice(Math.max(0, start, lastPos), fix.range[0]);
}
text += fix.text;
lastPos = fix.range[1];
}
text += originalText.slice(Math.max(0, start, lastPos), end);
return { range: [start, end], text };
}
/**
* Gets one fix object from the given descriptor.
* If the descriptor retrieves multiple fixes, this merges those to one.
* @param {MessageDescriptor} descriptor The report descriptor.
* @param {SourceCode} sourceCode The source code object to get text between fixes.
* @returns {({text: string, range: number[]}|null)} The fix for the descriptor
*/
function normalizeFixes(descriptor, sourceCode) {
if (typeof descriptor.fix !== "function") {
return null;
}
// @type {null | Fix | Fix[] | IterableIterator<Fix>}
const fix = descriptor.fix(ruleFixer);
// Merge to one.
if (fix && Symbol.iterator in fix) {
return mergeFixes(Array.from(fix), sourceCode);
}
assertValidFix(fix);
return fix;
}
/**
* Gets an array of suggestion objects from the given descriptor.
* @param {MessageDescriptor} descriptor The report descriptor.
* @param {SourceCode} sourceCode The source code object to get text between fixes.
* @param {Object} messages Object of meta messages for the rule.
* @returns {Array<SuggestionResult>} The suggestions for the descriptor
*/
function mapSuggestions(descriptor, sourceCode, messages) {
if (!descriptor.suggest || !Array.isArray(descriptor.suggest)) {
return [];
}
return descriptor.suggest
.map(suggestInfo => {
const computedDesc = suggestInfo.desc || messages[suggestInfo.messageId];
return {
...suggestInfo,
desc: interpolate(computedDesc, suggestInfo.data),
fix: normalizeFixes(suggestInfo, sourceCode)
};
})
// Remove suggestions that didn't provide a fix
.filter(({ fix }) => fix);
}
/**
* Creates information about the report from a descriptor
* @param {Object} options Information about the problem
* @param {string} options.ruleId Rule ID
* @param {(0|1|2)} options.severity Rule severity
* @param {(ASTNode|null)} options.node Node
* @param {string} options.message Error message
* @param {string} [options.messageId] The error message ID.
* @param {{start: SourceLocation, end: (SourceLocation|null)}} options.loc Start and end location
* @param {{text: string, range: (number[]|null)}} options.fix The fix object
* @param {Array<{text: string, range: (number[]|null)}>} options.suggestions The array of suggestions objects
* @returns {function(...args): ReportInfo} Function that returns information about the report
*/
function createProblem(options) {
const problem = {
ruleId: options.ruleId,
severity: options.severity,
message: options.message,
line: options.loc.start.line,
column: options.loc.start.column + 1,
nodeType: options.node && options.node.type || null
};
/*
* If this isn’t in the conditional, some of the tests fail
* because `messageId` is present in the problem object
*/
if (options.messageId) {
problem.messageId = options.messageId;
}
if (options.loc.end) {
problem.endLine = options.loc.end.line;
problem.endColumn = options.loc.end.column + 1;
}
if (options.fix) {
problem.fix = options.fix;
}
if (options.suggestions && options.suggestions.length > 0) {
problem.suggestions = options.suggestions;
}
return problem;
}
/**
* Validates that suggestions are properly defined. Throws if an error is detected.
* @param {Array<{ desc?: string, messageId?: string }>} suggest The incoming suggest data.
* @param {Object} messages Object of meta messages for the rule.
* @returns {void}
*/
function validateSuggestions(suggest, messages) {
if (suggest && Array.isArray(suggest)) {
suggest.forEach(suggestion => {
if (suggestion.messageId) {
const { messageId } = suggestion;
if (!messages) {
throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}', but no messages were present in the rule metadata.`);
}
if (!messages[messageId]) {
throw new TypeError(`context.report() called with a suggest option with a messageId '${messageId}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
}
if (suggestion.desc) {
throw new TypeError("context.report() called with a suggest option that defines both a 'messageId' and an 'desc'. Please only pass one.");
}
} else if (!suggestion.desc) {
throw new TypeError("context.report() called with a suggest option that doesn't have either a `desc` or `messageId`");
}
if (typeof suggestion.fix !== "function") {
throw new TypeError(`context.report() called with a suggest option without a fix function. See: ${suggestion}`);
}
});
}
}
/**
* Returns a function that converts the arguments of a `context.report` call from a rule into a reported
* problem for the Node.js API.
* @param {{ruleId: string, severity: number, sourceCode: SourceCode, messageIds: Object, disableFixes: boolean}} metadata Metadata for the reported problem
* @param {SourceCode} sourceCode The `SourceCode` instance for the text being linted
* @returns {function(...args): ReportInfo} Function that returns information about the report
*/
module.exports = function createReportTranslator(metadata) {
/*
* `createReportTranslator` gets called once per enabled rule per file. It needs to be very performant.
* The report translator itself (i.e. the function that `createReportTranslator` returns) gets
* called every time a rule reports a problem, which happens much less frequently (usually, the vast
* majority of rules don't report any problems for a given file).
*/
return (...args) => {
const descriptor = normalizeMultiArgReportCall(...args);
const messages = metadata.messageIds;
assertValidNodeInfo(descriptor);
let computedMessage;
if (descriptor.messageId) {
if (!messages) {
throw new TypeError("context.report() called with a messageId, but no messages were present in the rule metadata.");
}
const id = descriptor.messageId;
if (descriptor.message) {
throw new TypeError("context.report() called with a message and a messageId. Please only pass one.");
}
if (!messages || !Object.prototype.hasOwnProperty.call(messages, id)) {
throw new TypeError(`context.report() called with a messageId of '${id}' which is not present in the 'messages' config: ${JSON.stringify(messages, null, 2)}`);
}
computedMessage = messages[id];
} else if (descriptor.message) {
computedMessage = descriptor.message;
} else {
throw new TypeError("Missing `message` property in report() call; add a message that describes the linting problem.");
}
validateSuggestions(descriptor.suggest, messages);
return createProblem({
ruleId: metadata.ruleId,
severity: metadata.severity,
node: descriptor.node,
message: interpolate(computedMessage, descriptor.data),
messageId: descriptor.messageId,
loc: normalizeReportLoc(descriptor),
fix: metadata.disableFixes ? null : normalizeFixes(descriptor, metadata.sourceCode),
suggestions: metadata.disableFixes ? [] : mapSuggestions(descriptor, metadata.sourceCode, messages)
});
};
};