ConfigError: Config (unnamed): Key "plugins": Cannot redefine plugin "depend".

[tbroyer]

When used as follows, the plugin cannot be given the namespace depend:

import { defineConfig } from "eslint/config";
import * as depend from "eslint-plugin-depend";

export default defineConfig([
  {
    files: ["**/*.js"],
    plugins: {
      depend,
    },
    extends: ["depend/flat/recommended"],
  }
]);

It fails with:

Oops! Something went wrong! :(

ESLint: 9.23.0

ConfigError: Config (unnamed): Key "plugins": Cannot redefine plugin "depend".
    at rethrowConfigError (<redacted>/node_modules/@eslint/config-array/dist/cjs/index.cjs:328:8)
    at <redacted>/node_modules/@eslint/config-array/dist/cjs/index.cjs:1174:5
    at Array.reduce (<anonymous>)
    at FlatConfigArray.getConfigWithStatus (<redacted>/node_modules/@eslint/config-array/dist/cjs/index.cjs:1167:43)
    at FlatConfigArray.getConfig (<redacted>/node_modules/@eslint/config-array/dist/cjs/index.cjs:1196:15)
    at entryFilter (<redacted>/node_modules/eslint/lib/eslint/eslint-helpers.js:282:27)
    at async NodeHfs.<anonymous> (file://<redacted>/node_modules/@humanfs/core/src/hfs.js:574:24)
    at async NodeHfs.<anonymous> (file://<redacted>/node_modules/@humanfs/core/src/hfs.js:604:6)
    at async NodeHfs.walk (file://<redacted>/node_modules/@humanfs/core/src/hfs.js:614:3)
    at async globSearch (<redacted>/node_modules/eslint/lib/eslint/eslint-helpers.js:323:20)
    at async Promise.allSettled (index 0)
    at async globMultiSearch (<redacted>/node_modules/eslint/lib/eslint/eslint-helpers.js:414:18)
    at async findFiles (<redacted>/node_modules/eslint/lib/eslint/eslint-helpers.js:585:24)
    at async ESLint.lintFiles (<redacted>/node_modules/eslint/lib/eslint/eslint.js:756:21)
    at async Object.execute (<redacted>/node_modules/eslint/lib/cli.js:603:14)
    at async main (<redacted>/node_modules/eslint/bin/eslint.js:160:19)

This is due to the flat/recommended config using plugins: { depend: plugin } but then the associated plugin is not the same instance as the one from my configuration file (quite obviously, given the import * as depend).

Ideally, I think that the plugin object should be exported as the default export (whether you like it or not), like in the ESLint documentation about writing plugins (according to the docs, it also allows applying it from the command line with --plugin depend, e.g. npx eslint --plugin depend --rule 'depend/ban-dependencies: error'), then the "final" configuration would be:

import { defineConfig } from "eslint/config";
import depend from "eslint-plugin-depend";

export default defineConfig([
  {
    files: ["**/*.js"],
    plugins: {
      depend,
    },
    extends: ["depend/flat/recommended"],
  }
]);

(edit: removed the part about depend.plugin as it's actually not exported so my analysis was incorrect, I assume it was equivalent to depend: undefined in my testing and ESLint is OK with that)

[43081j]

ESLint already imports the plugin using a dynamic import whether you used the cli flags or not. So named exports should be fine (since it normalises default exports and cjs stuff internally to behave as if they were named).

So I think how we export it is fine already.

This seems like a miss by eslint, mistakenly assuming modules will always be the same reference.

Any idea where eslint is doing that internally?

[tbroyer]

Any idea where eslint is doing that internally?

https://github.com/eslint/eslint/blob/6d979ccc183454e616bc82a598db5402e9d63dcf/lib/config/flat-config-schema.js#L387-L399

Blame dates it to the very first implementation (4 years ago, as part of the rewrite and flat config): eslint/eslint@b08170b#diff-93aef33006c32545a3aa83cf3dfedd4959e55327e14abf62744aa845c5d789d8R270-R283

[tbroyer]

ESLint already imports the plugin using a dynamic import whether you used the cli flags or not.

Is that still the case with the flat config though? 🤔

[43081j]

aha you are correct in fact that --plugin has its own code path which relies on default existing

this probably shouldn't be the case anymore inside ESLint, but that is enough to convince me we should have a default export (alongside the named ones so we don't break things).

meanwhile, flat configs work because you import the plugin yourself. and legacy configs internally import the plugin too. so it is only --plugin that doesn't do this

[43081j]

@tbroyer any chance you can try 1.0.0-esm (the next tag in npm)

then if its all good, ill publish 1.0.0

[tbroyer]

Works great, thanks!

Changes made locally for testing

diff --git a/eslint.config.ts b/eslint.config.ts
index 252db72..3cf6946 100644
--- a/eslint.config.ts
+++ b/eslint.config.ts
@@ -1,7 +1,7 @@
 import { defineConfig } from "eslint/config";
 import js from "@eslint/js";
 import globals from "globals";
-import * as moduleReplacements from "eslint-plugin-depend";
+import depend from "eslint-plugin-depend";
 import security from "eslint-plugin-security";
 import tseslint from "typescript-eslint";
 import type { ESLint, Linter } from "eslint";
@@ -26,15 +26,14 @@ export default defineConfig([
     },
     plugins: {
       js,
-      // https://github.com/es-tooling/eslint-plugin-depend/issues/43
-      moduleReplacements,
+      depend,
       security,
       // https://github.com/typescript-eslint/typescript-eslint/issues/10899
       tseslint: tseslint.plugin as ESLint.Plugin,
     },
     extends: [
       "js/recommended",
-      "moduleReplacements/flat/recommended",
+      "depend/flat/recommended",
       "security/recommended",
       // https://github.com/typescript-eslint/typescript-eslint/issues/10934
       tseslint.configs.recommendedTypeChecked as Linter.Config,
diff --git a/package-lock.json b/package-lock.json
index d878515..0e1572a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,7 @@
         "@types/eslint-plugin-security": "^3.0.0",
         "@types/node": "^22.14.0",
         "eslint": "^9.24.0",
-        "eslint-plugin-depend": "^0.12.0",
+        "eslint-plugin-depend": "^1.0.0-esm",
         "eslint-plugin-security": "^3.0.1",
         "npm-run-all2": "^7.0.2",
         "prettier": "^3.5.3",
@@ -977,9 +977,9 @@
       }
     },
     "node_modules/eslint-plugin-depend": {
-      "version": "0.12.0",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-depend/-/eslint-plugin-depend-0.12.0.tgz",
-      "integrity": "sha512-bS5ESnC3eXDJPNv0RKkzRbLO45hRRLR/dleAUdbysXChWz1bAxa4MRh14EtDREn7fZieueqz4L7TfQQbzvdYHA==",
+      "version": "1.0.0-esm",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-depend/-/eslint-plugin-depend-1.0.0-esm.tgz",
+      "integrity": "sha512-0d1sk3OnwG306922RSgVI486vgAihCLxTCB8wwE9qUVpfzQ8og50ykLh0Uq6iyALGERvqY02Gl+vgR9fmmrMEA==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
diff --git a/package.json b/package.json
index f71c001..d351eda 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
     "@types/eslint-plugin-security": "^3.0.0",
     "@types/node": "^22.14.0",
     "eslint": "^9.24.0",
-    "eslint-plugin-depend": "^0.12.0",
+    "eslint-plugin-depend": "^1.0.0-esm",
     "eslint-plugin-security": "^3.0.1",
     "npm-run-all2": "^7.0.2",
     "prettier": "^3.5.3",

[43081j]

awesome, published in 1.0.0