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fix(vite): classify minified ESM deps chunks as ESM #11622

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Merged
NathanWalker merged 1 commit into from
Nov 9, 2026
+113 −33
Merged

fix(vite): classify minified ESM deps chunks as ESM #11622

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42 changes: 31 additions & 11 deletions packages/vite/hmr/server/deps-bundle.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ import { collectVendorModules } from '../shared/vendor/manifest-collect.js';
import { generatePlatformPolyfills } from '../shared/runtime/platform-polyfills.js';
import { getAngularLinkerFactory, runAngularLinker } from '../frameworks/angular/build/shared-linker.js';
import { getBlockedDeviceNodeModulesReason, isFlavorClientPackageSpecifier, resolveCandidateFilePath } from './websocket-module-specifiers.js';
import { extractDirectExportedNames, JS_IDENTIFIER_RE, parseExportSpecList } from './websocket-core-bridge.js';
import { extractDirectExportedNames, JS_IDENTIFIER_RE, maskJsComments, parseExportSpecList } from './websocket-core-bridge.js';
import { hasExistingDefaultExport } from './ns-core-cjs-shape.js';
import { getCjsNamedExports } from '../helpers/cjs-named-exports.js';
import { loadPersistedBootRecording } from './boot-recording.js';
Expand Down Expand Up @@ -850,7 +850,15 @@ export interface DepsModuleExportInfo {
opaqueCjs?: boolean;
}

const ESM_SYNTAX_RE = /^[ \t]*(?:import[\s{"'*]|export[\s{*])/m;
// ESM markers can sit anywhere on a line — minified chunks emit

@farfromrefug farfromrefug Nov 9, 2026

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those AI comments are far too long. I think it is best to limit any comment to 2/3 lines or the code will become a book to read with a few lines of code ;)
it applies to all comments

// `...;export{mt as g};` after other statements, and a line-anchored check
// misclassifies them as opaque CJS (the served shim then drops every named
// export). The pattern runs against a copy with comments and string/template/
// regex literal interiors blanked (positions preserved), so look-alike text
// inside literals can never match. The lookbehind keeps `$export`-style
// identifiers and `obj.import`/`obj.export` member access from matching.
const ESM_PREFIX = '(?<![.$\\u200c\\u200d\\p{ID_Continue}])';
const ESM_SYNTAX_RE = new RegExp(ESM_PREFIX + String.raw`(?:import[\s{"'*]|export[\s{*])`, 'u');

function resolveLocalReExportTarget(spec: string, importerPath: string, platform: string): string | null {
const base = path.resolve(path.dirname(importerPath), spec);
Expand Down Expand Up @@ -934,22 +942,34 @@ export function collectDepsModuleExportInfo(absPath: string, platform: string, s
} catch {
return { names: null, hasDefault: false };
}
if (!/\.mjs$/i.test(absPath) && !ESM_SYNTAX_RE.test(code)) return collectCjsExportInfo(code);
const names = new Set<string>(extractDirectExportedNames(code));
const maskedCode = maskJsComments(code, true);
if (!/\.mjs$/i.test(absPath) && !ESM_SYNTAX_RE.test(maskedCode)) return collectCjsExportInfo(code);
const names = new Set<string>(extractDirectExportedNames(maskedCode));
let match: RegExpExecArray | null;
const starAsRe = /\bexport\s+\*\s+as\s+([$_\p{ID_Start}][$\p{ID_Continue}]*)\s+from\s+["'][^"']+["']/gu;
while ((match = starAsRe.exec(code)) !== null) {
// Minifiers drop the spaces `export * as ns from "x"` keeps — allow none.
const starAsRe = new RegExp(ESM_PREFIX + String.raw`export\s*\*\s*as\s+([$_\p{ID_Start}][$\p{ID_Continue}]*)\s+from\s*["'][^"']*["']`, 'gu');
while ((match = starAsRe.exec(maskedCode)) !== null) {
names.add(match[1]);
}
const braceRe = /\bexport\s*\{([^}]+)\}/g;
while ((match = braceRe.exec(code)) !== null) {
const braceRe = new RegExp(ESM_PREFIX + String.raw`export\s*\{([^}]+)\}`, 'gu');
while ((match = braceRe.exec(maskedCode)) !== null) {
for (const { exportedName } of parseExportSpecList(match[1])) {
names.add(exportedName);
}
}
const starRe = /^[ \t]*export\s+\*\s+from\s+["']([^"']+)["']/gm;
while ((match = starRe.exec(code)) !== null) {
const spec = match[1];
// `export * from` carries the same mid-line minification hazard — find it
// on the masked copy, then read the specifier literal from the original
// code at the same offset (masked interiors are blanked).
const starRe = new RegExp(ESM_PREFIX + String.raw`export\s*\*\s*from\s*(["'])`, 'gu');
while ((match = starRe.exec(maskedCode)) !== null) {
const quoteIndex = match.index + match[0].length - 1;
const quote = match[1];
let specEnd = quoteIndex + 1;
while (specEnd < code.length && code[specEnd] !== quote) {
specEnd += code[specEnd] === '\\' ? 2 : 1;
}
if (specEnd >= code.length) return { names: null, hasDefault: false };
const spec = code.slice(quoteIndex + 1, specEnd);
const target = spec.startsWith('.') ? resolveLocalReExportTarget(spec, absPath, platform) : resolveBareReExportTarget(spec, absPath, platform);
if (!target) return { names: null, hasDefault: false };
const child = collectDepsModuleExportInfo(target, platform, seen);
Expand Down
104 changes: 82 additions & 22 deletions packages/vite/hmr/server/websocket-core-bridge.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -47,10 +47,12 @@ const REGEX_PRECEDING_KEYWORD_RE = /(?:^|[^$\w])(?:return|typeof|instanceof|in|o
/**
* Blank line and block comments (preserving newlines) so the regex export
* scanners never see a commented-out `export` declaration. String, template
* and regex literals are skipped so their contents are left intact.
* and regex literals are skipped so their contents are left intact — pass
* `literals` to blank their interiors too (keeping quotes/positions) so the
* scanners can also trust keyword matches as real syntax.
*/
export function maskJsComments(code: string): string {
if (!code || (code.indexOf('//') === -1 && code.indexOf('/*') === -1)) {
export function maskJsComments(code: string, literals = false): string {
if (!code || (!literals && code.indexOf('//') === -1 && code.indexOf('/*') === -1)) {
return code;
}
const chars = code.split('');
Expand All @@ -69,6 +71,77 @@ export function maskJsComments(code: string): string {
if ('(,=:[!&|?{};+-*%<>~^'.includes(code[j])) return true;
return REGEX_PRECEDING_KEYWORD_RE.test(code.slice(Math.max(0, j - 10), j + 1));
};
// Skip a regex literal starting at `at`; returns the index just past it.
const skipRegex = (at: number): number => {
let j = at + 1;
let inClass = false;
while (j < n && code[j] !== '\n') {
const r = code[j];
if (r === '\\') {
j += 2;
continue;
}
if (r === '[') inClass = true;
else if (r === ']') inClass = false;
else if (r === '/' && !inClass) break;
j++;
}
return j + 1;
};
// Skip a string/template literal starting at `at`; returns the index just
// past it. Template `${}` expressions may hold nested literals, comments
// and regexes — a naive next-backtick scan closes early and desyncs every
// later literal (`...it's...` inside a template opened a fake string).
const skipQuoted = (at: number): number => {
const quote = code[at];
let j = at + 1;
if (quote !== '`') {
while (j < n && code[j] !== quote) {
j += code[j] === '\\' ? 2 : 1;
}
return j + 1;
}
while (j < n) {
const t = code[j];
if (t === '\\') {
j += 2;
continue;
}
if (t === '`') return j + 1;
if (t === '$' && code[j + 1] === '{') {
j += 2;
let depth = 1;
while (j < n && depth) {
const e = code[j];
const e2 = code[j + 1];
if (e === "'" || e === '"' || e === '`') {
j = skipQuoted(j);
continue;
}
if (e === '/' && e2 === '/') {
const eol = code.indexOf('\n', j);
j = eol === -1 ? n : eol;
continue;
}
if (e === '/' && e2 === '*') {
const close = code.indexOf('*/', j + 2);
j = close === -1 ? n : close + 2;
continue;
}
if (e === '/' && slashStartsRegex(j)) {
j = skipRegex(j);
continue;
}
if (e === '{') depth++;
else if (e === '}') depth--;
j++;
}
continue;
}
j++;
}
return j;
};
let i = 0;
while (i < n) {
const c = code[i];
Expand All @@ -84,26 +157,13 @@ export function maskJsComments(code: string): string {
blank(i, stop);
i = stop;
} else if (c === "'" || c === '"' || c === '`') {
i++;
while (i < n && code[i] !== c) {
i += code[i] === '\\' ? 2 : 1;
}
i++;
const start = i;
i = skipQuoted(i);
if (literals) blank(start + 1, i - 1);
} else if (c === '/' && slashStartsRegex(i)) {
i++;
let inClass = false;
while (i < n && code[i] !== '\n') {
const r = code[i];
if (r === '\\') {
i += 2;
continue;
}
if (r === '[') inClass = true;
else if (r === ']') inClass = false;
else if (r === '/' && !inClass) break;
i++;
}
i++;
const start = i;
i = skipRegex(i);
if (literals) blank(start, i);
} else {
i++;
}
Expand Down
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