add a config option to disallow the cache clean command (#6610)

## What's the problem this PR addresses?

At [Datadog](https://github.com/datadog) we are using `yarn` inside a
huge monorepository using the PnP linker and Zero-Installs with all the
dependencies versioned through git.

The issue we have is that people frequently have the tendency to think
that this kind of environment works like others, and that cleaning the
cache is the way to go whenever they encounter an install issue (like
deleting `node_modules`).

This is obviously not the case and we have to tell them to restore their
packages from the git remote when that happens, which is a bit
cumbersome.

_see also: https://github.com/yarnpkg/berry/discussions/6518_

## How did you fix it?

This PR adds a non-breaking option inside the `.yarnrc` file to disallow
running `yarn clean cache`.

cc @arcanis 

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.yarn/versions/c6c3dd7a.yml

@@ -0,0 +1,34 @@
+releases:
+  "@yarnpkg/cli": minor
+  "@yarnpkg/core": minor
+  "@yarnpkg/plugin-essentials": minor
+
+declined:
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-exec"
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-git"
+  - "@yarnpkg/plugin-github"
+  - "@yarnpkg/plugin-http"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-link"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnp"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/extensions"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"

packages/acceptance-tests/pkg-tests-specs/sources/commands/cache/clean.test.js

@@ -37,5 +37,16 @@ describe(`Commands`, () => {
       expect(xfs.existsSync(`${path}/.yarn/cache`)).toEqual(false);
       expect(xfs.existsSync(`${path}/.yarn/global/cache`)).toEqual(false);
     }));
+
+    test(`it should follow the enableCacheClean configuration`, makeTemporaryEnv({
+      dependencies: {
+        [`no-deps`]: `1.0.0`,
+      },
+    }, {
+      enableCacheClean: false,
+    }, async ({path, run, source}) => {
+      await run(`install`);
+      await expect(run(`cache`, `clean`)).rejects.toThrowError();
+    }));
   });
 });

packages/plugin-essentials/sources/commands/cache/clean.ts

@@ -1,7 +1,7 @@
 import {BaseCommand}                               from '@yarnpkg/cli';
 import {Configuration, Cache, StreamReport, Hooks} from '@yarnpkg/core';
 import {xfs}                                       from '@yarnpkg/fslib';
-import {Command, Option, Usage}                    from 'clipanion';
+import {Command, Option, Usage, UsageError}        from 'clipanion';
 
 // eslint-disable-next-line arca/no-default-export
 export default class CacheCleanCommand extends BaseCommand {
@@ -34,6 +34,10 @@ export default class CacheCleanCommand extends BaseCommand {
 
   async execute() {
     const configuration = await Configuration.find(this.context.cwd, this.context.plugins);
+
+    if (!configuration.get(`enableCacheClean`))
+      throw new UsageError(`Cache cleaning is currently disabled. To enable it, set \`enableCacheClean: true\` in your configuration file. Note: Cache cleaning is typically not required and should be avoided when using Zero-Installs.`);
+
     const cache = await Cache.find(configuration);
 
     const report = await StreamReport.start({

packages/yarnpkg-core/sources/Configuration.ts

@@ -567,6 +567,11 @@ export const coreDefinitions: {[coreSettingName: string]: SettingsDefinition} =
     type: SettingsType.BOOLEAN,
     default: false,
   },
+  enableCacheClean: {
+    description: `If false, disallows the \`cache clean\` command`,
+    type: SettingsType.BOOLEAN,
+    default: true,
+  },
   checksumBehavior: {
     description: `Enumeration defining what to do when a checksum doesn't match expectations`,
     type: SettingsType.STRING,