node fixes, updates

4 files changed, 302 insertions, 18 deletions

diff --git a/node_modules/@babel/helpers/scripts/build-helper-metadata.js b/node_modules/@babel/helpers/scripts/build-helper-metadata.js
new file mode 100644
index 00000000..6a54fa0e
--- /dev/null
+++ b/node_modules/@babel/helpers/scripts/build-helper-metadata.js
@@ -0,0 +1,209 @@
+// NOTE: This file must be compatible with old Node.js versions, since it runs
+// during testing.
+
+/**
+ * @typedef {Object} HelperMetadata
+ * @property {string[]} globals
+ * @property {{ [name: string]: string[] }} locals
+ * @property {{ [name: string]: string[] }} dependencies
+ * @property {string[]} exportBindingAssignments
+ * @property {string} exportName
+ */
+
+/**
+ * Given a file AST for a given helper, get a bunch of metadata about it so that Babel can quickly render
+ * the helper is whatever context it is needed in.
+ *
+ * @param {typeof import("@babel/core")} babel
+ *
+ * @returns {HelperMetadata}
+ */
+export function getHelperMetadata(babel, code, helperName) {
+  const globals = new Set();
+  // Maps imported identifier name -> helper name
+  const dependenciesBindings = new Map();
+
+  let exportName;
+  const exportBindingAssignments = [];
+  // helper name -> reference paths
+  const dependencies = new Map();
+  // local variable name -> reference paths
+  const locals = new Map();
+
+  const spansToRemove = [];
+
+  const validateDefaultExport = decl => {
+    if (exportName) {
+      throw new Error(
+        `Helpers can have only one default export (in ${helperName})`
+      );
+    }
+
+    if (!decl.isFunctionDeclaration() || !decl.node.id) {
+      throw new Error(
+        `Helpers can only export named function declarations (in ${helperName})`
+      );
+    }
+  };
+
+  /** @type {import("@babel/traverse").Visitor} */
+  const dependencyVisitor = {
+    Program(path) {
+      for (const child of path.get("body")) {
+        if (child.isImportDeclaration()) {
+          if (
+            child.get("specifiers").length !== 1 ||
+            !child.get("specifiers.0").isImportDefaultSpecifier()
+          ) {
+            throw new Error(
+              `Helpers can only import a default value (in ${helperName})`
+            );
+          }
+          dependenciesBindings.set(
+            child.node.specifiers[0].local.name,
+            child.node.source.value
+          );
+          dependencies.set(child.node.source.value, []);
+          spansToRemove.push([child.node.start, child.node.end]);
+          child.remove();
+        }
+      }
+      for (const child of path.get("body")) {
+        if (child.isExportDefaultDeclaration()) {
+          const decl = child.get("declaration");
+          validateDefaultExport(decl);
+
+          exportName = decl.node.id.name;
+          spansToRemove.push([child.node.start, decl.node.start]);
+          child.replaceWith(decl.node);
+        } else if (
+          child.isExportNamedDeclaration() &&
+          child.node.specifiers.length === 1 &&
+          child.get("specifiers.0.exported").isIdentifier({ name: "default" })
+        ) {
+          const { name } = child.node.specifiers[0].local;
+
+          validateDefaultExport(child.scope.getBinding(name).path);
+
+          exportName = name;
+          spansToRemove.push([child.node.start, child.node.end]);
+          child.remove();
+        } else if (
+          process.env.IS_BABEL_OLD_E2E &&
+          child.isExportNamedDeclaration() &&
+          child.node.specifiers.length === 0
+        ) {
+          spansToRemove.push([child.node.start, child.node.end]);
+          child.remove();
+        } else if (
+          child.isExportAllDeclaration() ||
+          child.isExportNamedDeclaration()
+        ) {
+          throw new Error(`Helpers can only export default (in ${helperName})`);
+        }
+      }
+
+      path.scope.crawl();
+
+      const bindings = path.scope.getAllBindings();
+      Object.keys(bindings).forEach(name => {
+        if (dependencies.has(name)) return;
+
+        const binding = bindings[name];
+
+        const references = [
+          ...binding.path.getBindingIdentifierPaths(true)[name].map(makePath),
+          ...binding.referencePaths.map(makePath),
+        ];
+        for (const violation of binding.constantViolations) {
+          violation.getBindingIdentifierPaths(true)[name].forEach(path => {
+            references.push(makePath(path));
+          });
+        }
+
+        locals.set(name, references);
+      });
+    },
+    ReferencedIdentifier(child) {
+      const name = child.node.name;
+      const binding = child.scope.getBinding(name);
+      if (!binding) {
+        if (dependenciesBindings.has(name)) {
+          dependencies
+            .get(dependenciesBindings.get(name))
+            .push(makePath(child));
+        } else if (name !== "arguments" || child.scope.path.isProgram()) {
+          globals.add(name);
+        }
+      }
+    },
+    AssignmentExpression(child) {
+      const left = child.get("left");
+
+      if (!(exportName in left.getBindingIdentifiers())) return;
+
+      if (!left.isIdentifier()) {
+        throw new Error(
+          `Only simple assignments to exports are allowed in helpers (in ${helperName})`
+        );
+      }
+
+      const binding = child.scope.getBinding(exportName);
+
+      if (binding && binding.scope.path.isProgram()) {
+        exportBindingAssignments.push(makePath(child));
+      }
+    },
+  };
+
+  babel.transformSync(code, {
+    configFile: false,
+    babelrc: false,
+    plugins: [() => ({ visitor: dependencyVisitor })],
+  });
+
+  if (!exportName) throw new Error("Helpers must have a named default export.");
+
+  // Process these in reverse so that mutating the references does not invalidate any later paths in
+  // the list.
+  exportBindingAssignments.reverse();
+
+  spansToRemove.sort(([start1], [start2]) => start2 - start1);
+  for (const [start, end] of spansToRemove) {
+    code = code.slice(0, start) + code.slice(end);
+  }
+
+  return [
+    code,
+    {
+      globals: Array.from(globals),
+      locals: Object.fromEntries(locals),
+      dependencies: Object.fromEntries(dependencies),
+      exportBindingAssignments,
+      exportName,
+    },
+  ];
+}
+
+function makePath(path) {
+  const parts = [];
+
+  for (; path.parentPath; path = path.parentPath) {
+    parts.push(path.key);
+    if (path.inList) parts.push(path.listKey);
+  }
+
+  return parts.reverse().join(".");
+}
+
+export function stringifyMetadata(metadata) {
+  return `\
+    {
+      globals: ${JSON.stringify(metadata.globals)},
+      locals: ${JSON.stringify(metadata.locals)},
+      exportBindingAssignments: ${JSON.stringify(metadata.exportBindingAssignments)},
+      exportName: ${JSON.stringify(metadata.exportName)},
+      dependencies: ${JSON.stringify(metadata.dependencies)},
+    }
+  `;
+}
diff --git a/node_modules/@babel/helpers/scripts/generate-helpers.js b/node_modules/@babel/helpers/scripts/generate-helpers.js
index 45182c95..9eeb95a2 100644
--- a/node_modules/@babel/helpers/scripts/generate-helpers.js
+++ b/node_modules/@babel/helpers/scripts/generate-helpers.js
@@ -3,13 +3,17 @@ import fs from "fs";
 import { join } from "path";
 import { URL, fileURLToPath } from "url";
 import { minify } from "terser";
-import { transformSync } from "@babel/core";
-import presetTypescript from "@babel/preset-typescript";
-import { gzipSync } from "zlib";
+import { babel, presetTypescript } from "$repo-utils/babel-top-level";
 import { IS_BABEL_8 } from "$repo-utils";
+import { gzipSync } from "zlib";
+
+import {
+  getHelperMetadata,
+  stringifyMetadata,
+} from "./build-helper-metadata.js";
 
 const HELPERS_FOLDER = new URL("../src/helpers", import.meta.url);
-const IGNORED_FILES = new Set(["package.json"]);
+const IGNORED_FILES = new Set(["package.json", "tsconfig.json"]);
 
 export default async function generateHelpers() {
   let output = `/*
@@ -18,17 +22,37 @@ export default async function generateHelpers() {
  */
 
 import template from "@babel/template";
+import type * as t from "@babel/types";
+
+interface Helper {
+  minVersion: string;
+  ast: () => t.Program;
+  metadata: HelperMetadata;
+}
+
+export interface HelperMetadata {
+  globals: string[];
+  locals: { [name: string]: string[] };
+  dependencies: { [name: string]: string[] };
+  exportBindingAssignments: string[];
+  exportName: string;
+}
 
-function helper(minVersion: string, source: string) {
+function helper(minVersion: string, source: string, metadata: HelperMetadata): Helper {
   return Object.freeze({
     minVersion,
     ast: () => template.program.ast(source, { preserveComments: true }),
+    metadata,
   })
 }
 
-export default Object.freeze({
+export { helpers as default };
+const helpers: Record<string, Helper> = {
+  __proto__: null,
 `;
 
+  let babel7extraOutput = "";
+
   for (const file of (await fs.promises.readdir(HELPERS_FOLDER)).sort()) {
     if (IGNORED_FILES.has(file)) continue;
     if (file.startsWith(".")) continue; // ignore e.g. vim swap files
@@ -52,14 +76,11 @@ export default Object.freeze({
     }
     const { minVersion } = minVersionMatch.groups;
 
-    if (IS_BABEL_8() && code.includes("@onlyBabel7")) {
-      continue;
-    }
-
+    const onlyBabel7 = code.includes("@onlyBabel7");
     const mangleFns = code.includes("@mangleFns");
     const noMangleFns = [];
 
-    code = transformSync(code, {
+    code = babel.transformSync(code, {
       configFile: false,
       babelrc: false,
       filename: filePath,
@@ -76,7 +97,41 @@ export default Object.freeze({
         /**
          * @type {import("@babel/core").PluginObj}
          */
-        {
+        ({ types: t }) => ({
+          // These pre/post hooks are needed because the TS transform is,
+          // when building in the old Babel e2e test, removing the
+          // `export { OverloadYield as default }` in the OverloadYield helper.
+          // TODO: Remove in Babel 8.
+          pre(file) {
+            if (!process.env.IS_BABEL_OLD_E2E) return;
+            file.metadata.exportName = null;
+            file.path.traverse({
+              ExportSpecifier(path) {
+                if (path.node.exported.name === "default") {
+                  file.metadata.exportName = path.node.local.name;
+                }
+              },
+            });
+          },
+          post(file) {
+            if (!process.env.IS_BABEL_OLD_E2E) return;
+            if (!file.metadata.exportName) return;
+            file.path.traverse({
+              ExportNamedDeclaration(path) {
+                if (
+                  !path.node.declaration &&
+                  path.node.specifiers.length === 0
+                ) {
+                  path.node.specifiers.push(
+                    t.exportSpecifier(
+                      t.identifier(file.metadata.exportName),
+                      t.identifier("default")
+                    )
+                  );
+                }
+              },
+            });
+          },
           visitor: {
             ImportDeclaration(path) {
               const source = path.node.source;
@@ -96,7 +151,7 @@ export default Object.freeze({
               }
             },
           },
-        },
+        }),
       ],
     }).code;
     code = (
@@ -115,15 +170,38 @@ export default Object.freeze({
       })
     ).code;
 
-    output += `\
+    let metadata;
+    // eslint-disable-next-line prefer-const
+    [code, metadata] = getHelperMetadata(babel, code, helperName);
+
+    const helperStr = `\
   // size: ${code.length}, gzip size: ${gzipSync(code).length}
   ${JSON.stringify(helperName)}: helper(
     ${JSON.stringify(minVersion)},
     ${JSON.stringify(code)},
+    ${stringifyMetadata(metadata)}
   ),
 `;
+
+    if (onlyBabel7) {
+      if (!IS_BABEL_8()) babel7extraOutput += helperStr;
+    } else {
+      output += helperStr;
+    }
+  }
+
+  output += "};";
+
+  if (babel7extraOutput) {
+    output += `
+
+if (!process.env.BABEL_8_BREAKING) {
+  Object.assign(helpers, {
+    ${babel7extraOutput}
+  });
+}
+`;
   }
 
-  output += "});";
   return output;
 }
diff --git a/node_modules/@babel/helpers/scripts/generate-regenerator-runtime.js b/node_modules/@babel/helpers/scripts/generate-regenerator-runtime.js
index 34a46d63..73c301ce 100644
--- a/node_modules/@babel/helpers/scripts/generate-regenerator-runtime.js
+++ b/node_modules/@babel/helpers/scripts/generate-regenerator-runtime.js
@@ -1,5 +1,3 @@
-/* eslint-disable import/no-extraneous-dependencies */
-
 import fs from "fs";
 import { createRequire } from "module";
 
diff --git a/node_modules/@babel/helpers/scripts/package.json b/node_modules/@babel/helpers/scripts/package.json
deleted file mode 100644
index 5ffd9800..00000000
--- a/node_modules/@babel/helpers/scripts/package.json
+++ /dev/null
@@ -1 +0,0 @@
-{ "type": "module" }