@mui/icons-material 9.0.0 can't be hosted on some private NPM registries

[humodz]

This is not an issue with MUI per se, but I think this information might be of interest.

Due to the size of v9's package.json, part of the publish request ends up very large, exceeding the ~1MB limit of some private registries like AWS CodeArtifact and (afaik, might be wrong) Artifactory. As a consequence, it's impossible to host that version on these registries.

Again, I'm aware this is not really MUI's problem, but would the MUI team consider reducing package.json to a reasonable size, like it is in version 7?

Search keywords:

[mj12albert]

@humodz Do you mean the bundle size?
According to https://bundlephobia.com/package/@mui/icons-material@9.0.0

The size didn't change much between versions

[humodz]

No, I mean the actual package.json. It has 50K lines of this:

  "exports": {
    "./package.json": "./package.json",
    ".": {
      "require": "./index.js",
      "import": "./index.mjs",
      "default": "./index.mjs"
    },
    "./Abc": {
      "require": "./Abc.js",
      "import": "./Abc.mjs",
      "default": "./Abc.mjs"
    },
    "./AbcOutlined": {
      "require": "./AbcOutlined.js",
      "import": "./AbcOutlined.mjs",
      "default": "./AbcOutlined.mjs"
    }, 
    // repeats for every file in the package

Meanwhile, v7 looks like this:

  "exports": {
    ".": {
      "require": {
        "types": "./index.d.ts",
        "default": "./index.js"
      },
      "default": {
        "types": "./esm/index.d.ts",
        "default": "./esm/index.js"
      }
    },
    "./*": {
      "require": {
        "types": "./*.d.ts",
        "default": "./*.js"
      },
      "default": {
        "types": "./esm/*.d.ts",
        "default": "./esm/*.js"
      }
    },
    "./esm": null,
    "./utils/*": null
  },

If you try to "npm publish" v9, the request body that npm sends looks like this:

{
  "_id": "@mui/icons-material",
  "name": "@mui/icons-material",
  "description": "Material Design icons distributed as SVG React components.",
  "dist-tags": {
    "latest": "9.0.0"
  },
  "versions": {
    "9.0.0": { /* contents of package.json */ }
  },
  // ... some other stuff
}

The issue is that CodeArtifact has a size limit on that "versions" section, which is lower than the size of package.json

[mj12albert]

@siriwatknp @Janpot WDYT about this issue and these findings by Codex:

Issue #48355 is a real bug, not user error.

The root cause is in the publish path for @mui/icons-material. The source manifest is already compact in packages/mui-icons-material/package.json: it uses ./* plus null exclusions at lines 82-86. But the publish merge step in packages/mui-icons-material/scripts/merge-package-json.mjs replaces that with lib/package.json exports at line 26. That lib manifest is the huge expanded map starting at packages/mui-icons-material/lib/package.json:50. Locally, that file is 1,741,945 bytes with 10,753 export entries. A compact equivalent for the published package is about 1,444 bytes with 5 entries.

This lines up with PR #47670 (https://github.com/mui/material-ui/pull/47670), merged on February 23, 2026, which explicitly said globs were expanded “to have maximum bundler support”. That makes this a packaging regression from the flat-build rollout, not an issue with the icons themselves.

Proposed fix:

1. Keep the current lib/package.json behavior untouched.
2. Change only packages/mui-icons-material/scripts/merge-package-json.mjs so the published build/package.json uses the compact root export patterns instead of copying the expanded lib export table wholesale.
3. Preserve . from lib/package.json, preserve null exclusions from the root manifest, and emit a compact ./* dual-bundle mapping:

{
  "./package.json": "./package.json",
  ".": { "require": "./index.js", "import": "./index.mjs", "default": "./index.mjs" },
  "./*": { "require": "./*.js", "import": "./*.mjs", "default": "./*.mjs" },
  "./index*": null,
  "./utils/*": null
}

4. Add a new package-local test for merge-package-json that asserts concrete icon keys like ./Abc are absent from the published manifest and the wildcard/null entries are present.

[Janpot]

WDYT about this issue

IIRC The wildcard doesn't work correctly in some bundlers and/or our codesandbox demos. cc @brijeshb42 I believe you have more insight about this.

[brijeshb42]

Yeah. It was mainly done to support codesandbox. All our demos won't work without it. The issue is specifically that it won't be able to resolve the index.js/mjs files if I remember correctly.

[Janpot]

For now I'd say this is a too niche issue to go back on the package format, but we can keep it around to collect more feedback.

If this is a hard blocker for you, my recommendation would be to rewrite the package.json before publishing to your own registry. This should be easily scriptable. Just note, the internal directory layout of our packages is an implementation detail, not guaranteed to be semver stable. So make sure you add a few assertions that icons are in the expected location before publishing.