Downgrade packages that are incompatible with Node v8 (#113)

- Downgrade espree
- Downgrade semver
- Change the parser so that if the user explicitly installs espree v8 and specifies espree for parserOptions.parser, it will be use.

Author: ota-meshi

Diff for: .gitignore

@@ -6,3 +6,4 @@
 /index.*
 /npm-debug.log
 /test.js
+/test/fixtures/espree-v8/node_modules

Diff for: package.json

@@ -16,10 +16,10 @@
     "debug": "^4.1.1",
     "eslint-scope": "^5.1.1",
     "eslint-visitor-keys": "^1.1.0",
-    "espree": "^8.0.0",
+    "espree": "^6.2.1",
     "esquery": "^1.4.0",
     "lodash": "^4.17.21",
-    "semver": "^7.3.5"
+    "semver": "^6.3.0"
   },
   "devDependencies": {
     "@mysticatea/eslint-plugin": "^13.0.0",

Diff for: scripts/update-fixtures-ast.js

@@ -13,6 +13,7 @@ const fs = require("fs")
 const path = require("path")
 const parser = require("../")
 const escope = require("eslint-scope")
+const semver = require("semver")
 
 //------------------------------------------------------------------------------
 // Helpers
@@ -22,7 +23,7 @@ const ROOT = path.join(__dirname, "../test/fixtures/ast")
 const TARGETS = fs.readdirSync(ROOT)
 const PARSER_OPTIONS = {
     comment: true,
-    ecmaVersion: 2022,
+    ecmaVersion: 2020,
     loc: true,
     range: true,
     tokens: true,
@@ -201,6 +202,18 @@ function analyze(ast, parserOptions) {
 //------------------------------------------------------------------------------
 
 for (const name of TARGETS) {
+    const requirementsPath = path.join(ROOT, `${name}/requirements.json`)
+    const requirements = fs.existsSync(requirementsPath)
+        ? JSON.parse(fs.readFileSync(requirementsPath, "utf8"))
+        : {}
+    if (
+        Object.entries(requirements).some(([pkgName, pkgVersion]) => {
+            const pkg = require(`${pkgName}/package.json`)
+            return !semver.satisfies(pkg.version, pkgVersion)
+        })
+    ) {
+        continue
+    }
     const sourcePath = path.join(ROOT, `${name}/source.vue`)
     const optionsPath = path.join(ROOT, `${name}/parser-options.json`)
     const astPath = path.join(ROOT, `${name}/ast.json`)

Diff for: src/common/create-require.ts

@@ -0,0 +1,18 @@
+import Module from "module"
+import path from "path"
+export const createRequire: (filename: string) => (modname: string) => any =
+    // Added in v12.2.0
+    (Module as any).createRequire ||
+    // Added in v10.12.0, but deprecated in v12.2.0.
+    // eslint-disable-next-line @mysticatea/node/no-deprecated-api
+    Module.createRequireFromPath ||
+    // Polyfill - This is not executed on the tests on node@>=10.
+    /* istanbul ignore next */
+    ((modname) => {
+        const mod = new Module(modname)
+
+        mod.filename = modname
+        mod.paths = (Module as any)._nodeModulePaths(path.dirname(modname))
+        ;(mod as any)._compile("module.exports = require;", modname)
+        return mod.exports
+    })

Diff for: src/common/espree.ts

@@ -2,8 +2,10 @@ import type { ESLintExtendedProgram, ESLintProgram } from "../ast"
 import type { ParserOptions } from "../common/parser-options"
 import { getLinterRequire } from "./linter-require"
 // @ts-expect-error -- ignore
-import * as espree from "espree"
+import * as dependencyEspree from "espree"
 import { lte, lt } from "semver"
+import { createRequire } from "./create-require"
+import path from "path"
 
 /**
  * The interface of a result of ESLint custom parser.
@@ -17,66 +19,59 @@ export interface ESLintCustomParser {
     parse(code: string, options: any): ESLintCustomParserResult
     parseForESLint?(code: string, options: any): ESLintCustomParserResult
 }
-type OldEspree = ESLintCustomParser & {
-    latestEcmaVersion?: number
-    version: string
-}
 type Espree = ESLintCustomParser & {
-    latestEcmaVersion: number
+    latestEcmaVersion?: number
     version: string
 }
-let espreeCache: OldEspree | Espree | null = null
+let espreeCache: Espree | null = null
 
 /**
  * Gets the espree that the given ecmaVersion can parse.
  */
 export function getEspreeFromEcmaVersion(
     ecmaVersion: ParserOptions["ecmaVersion"],
-): OldEspree | Espree {
+): Espree {
     const linterEspree = getEspreeFromLinter()
-    if (
-        linterEspree.version != null &&
-        lte(espree.version, linterEspree.version)
-    ) {
-        // linterEspree is newest
-        return linterEspree
-    }
     if (ecmaVersion == null) {
         return linterEspree
     }
     if (ecmaVersion === "latest") {
-        return espree
+        return getNewestEspree()
     }
-    if (normalizeEcmaVersion(ecmaVersion) <= getLinterLatestEcmaVersion()) {
+    if (
+        normalizeEcmaVersion(ecmaVersion) <= getLatestEcmaVersion(linterEspree)
+    ) {
         return linterEspree
     }
-    return espree
+    const userEspree = getEspreeFromUser()
+    if (normalizeEcmaVersion(ecmaVersion) <= getLatestEcmaVersion(userEspree)) {
+        return userEspree
+    }
+    return linterEspree
+}
 
-    function getLinterLatestEcmaVersion() {
-        if (linterEspree.latestEcmaVersion == null) {
-            for (const { v, latest } of [
-                { v: "6.1.0", latest: 2020 },
-                { v: "4.0.0", latest: 2019 },
-            ]) {
-                if (lte(v, linterEspree.version)) {
-                    return latest
-                }
-            }
-            return 2018
-        }
-        return normalizeEcmaVersion(linterEspree.latestEcmaVersion)
+/**
+ * Load `espree` from the user dir.
+ */
+export function getEspreeFromUser(): Espree {
+    try {
+        const cwd = process.cwd()
+        const relativeTo = path.join(cwd, "__placeholder__.js")
+        return createRequire(relativeTo)("espree")
+    } catch {
+        return getEspreeFromLinter()
     }
 }
 
 /**
  * Load `espree` from the loaded ESLint.
  * If the loaded ESLint was not found, just returns `require("espree")`.
  */
-export function getEspreeFromLinter(): Espree | OldEspree {
+export function getEspreeFromLinter(): Espree {
     if (!espreeCache) {
         espreeCache = getLinterRequire()?.("espree")
         if (!espreeCache) {
-            espreeCache = espree
+            espreeCache = dependencyEspree
         }
     }
 
@@ -87,14 +82,19 @@ export function getEspreeFromLinter(): Espree | OldEspree {
  * Load the newest `espree` from the loaded ESLint or dependency.
  */
 function getNewestEspree(): Espree {
+    let newest = dependencyEspree
     const linterEspree = getEspreeFromLinter()
     if (
-        linterEspree.version == null ||
-        lte(linterEspree.version, espree.version)
+        linterEspree.version != null &&
+        lte(newest.version, linterEspree.version)
     ) {
-        return espree
+        newest = linterEspree
     }
-    return linterEspree as Espree
+    const userEspree = getEspreeFromUser()
+    if (userEspree.version != null && lte(newest.version, userEspree.version)) {
+        newest = userEspree
+    }
+    return newest
 }
 
 export function getEcmaVersionIfUseEspree(
@@ -106,7 +106,7 @@ export function getEcmaVersionIfUseEspree(
     }
 
     if (parserOptions.ecmaVersion === "latest") {
-        return normalizeEcmaVersion(getNewestEspree().latestEcmaVersion)
+        return normalizeEcmaVersion(getLatestEcmaVersion(getNewestEspree()))
     }
     if (parserOptions.ecmaVersion == null) {
         const defVer = getDefaultEcmaVersion()
@@ -120,7 +120,7 @@ function getDefaultEcmaVersion(): number {
         return 5
     }
     // Perhaps the version 9 will change the default to "latest".
-    return normalizeEcmaVersion(getNewestEspree().latestEcmaVersion)
+    return normalizeEcmaVersion(getLatestEcmaVersion(getNewestEspree()))
 }
 
 /**
@@ -132,3 +132,18 @@ function normalizeEcmaVersion(version: number) {
     }
     return version
 }
+
+function getLatestEcmaVersion(espree: Espree) {
+    if (espree.latestEcmaVersion == null) {
+        for (const { v, latest } of [
+            { v: "6.1.0", latest: 2020 },
+            { v: "4.0.0", latest: 2019 },
+        ]) {
+            if (lte(v, espree.version)) {
+                return latest
+            }
+        }
+        return 2018
+    }
+    return normalizeEcmaVersion(espree.latestEcmaVersion)
+}

Diff for: src/common/linter-require.ts

@@ -1,22 +1,5 @@
-import Module from "module"
 import path from "path"
-
-const createRequire: (filename: string) => (modname: string) => any =
-    // Added in v12.2.0
-    (Module as any).createRequire ||
-    // Added in v10.12.0, but deprecated in v12.2.0.
-    // eslint-disable-next-line @mysticatea/node/no-deprecated-api
-    Module.createRequireFromPath ||
-    // Polyfill - This is not executed on the tests on node@>=10.
-    /* istanbul ignore next */
-    ((modname) => {
-        const mod = new Module(modname)
-
-        mod.filename = modname
-        mod.paths = (Module as any)._nodeModulePaths(path.dirname(modname))
-        ;(mod as any)._compile("module.exports = require;", modname)
-        return mod.exports
-    })
+import { createRequire } from "./create-require"
 
 function isLinterPath(p: string): boolean {
     return (

Diff for: src/script/index.ts

@@ -44,8 +44,9 @@ import {
 } from "./scope-analyzer"
 import type { ESLintCustomParser } from "../common/espree"
 import {
-    getEspreeFromEcmaVersion,
     getEcmaVersionIfUseEspree,
+    getEspreeFromUser,
+    getEspreeFromEcmaVersion,
 } from "../common/espree"
 import type { ParserOptions } from "../common/parser-options"
 import {
@@ -521,6 +522,14 @@ export interface ExpressionParseResult<T extends Node> {
     variables: Variable[]
 }
 
+function loadParser(parser: string) {
+    if (parser !== "espree") {
+        // eslint-disable-next-line @mysticatea/ts/no-require-imports
+        return require(parser)
+    }
+    return getEspreeFromUser()
+}
+
 /**
  * Parse the given source code.
  *
@@ -534,9 +543,9 @@ export function parseScript(
 ): ESLintExtendedProgram {
     const parser: ESLintCustomParser =
         typeof parserOptions.parser === "string"
-            ? // eslint-disable-next-line @mysticatea/ts/no-require-imports
-              require(parserOptions.parser)
+            ? loadParser(parserOptions.parser)
             : getEspreeFromEcmaVersion(parserOptions.ecmaVersion)
+
     const result: any =
         typeof parser.parseForESLint === "function"
             ? parser.parseForESLint(code, parserOptions)

Diff for: test/ast.js

@@ -26,7 +26,7 @@ const ROOT = path.join(__dirname, "fixtures/ast")
 const TARGETS = fs.readdirSync(ROOT)
 const PARSER_OPTIONS = {
     comment: true,
-    ecmaVersion: 2022,
+    ecmaVersion: 2020,
     loc: true,
     range: true,
     tokens: true,
@@ -100,7 +100,7 @@ function getTree(source, parserOptions) {
         source,
         {
             parser: PARSER,
-            parserOptions: Object.assign({ ecmaVersion: 2022 }, parserOptions),
+            parserOptions: Object.assign({ ecmaVersion: 2020 }, parserOptions),
             rules: { maketree: "error" },
         },
         undefined,