Add ESLINT constraints to detect inter-group dependencies (#194810)

## Summary

Addresses https://github.com/elastic/kibana-team/issues/1175

As part of the **Sustainable Kibana Architecture** initiative, this PR
sets the foundation to start classifying plugins in isolated groups,
matching our current solutions / project types:

* It adds support for the following fields in the packages' manifests
(kibana.jsonc):
* `group?: 'search' | 'security' | 'observability' | 'platform' |
'common'`
  * `visibility?: 'private' | 'shared'`

* It proposes a folder structure to automatically infer groups:
```javascript
  'src/platform/plugins/shared': {
    group: 'platform',
    visibility: 'shared',
  },
  'src/platform/plugins/internal': {
    group: 'platform',
    visibility: 'private',
  },
  'x-pack/platform/plugins/shared': {
    group: 'platform',
    visibility: 'shared',
  },
  'x-pack/platform/plugins/internal': {
    group: 'platform',
    visibility: 'private',
  },
  'x-pack/solutions/observability/plugins': {
    group: 'observability',
    visibility: 'private',
  },
  'x-pack/solutions/security/plugins': {
    group: 'security',
    visibility: 'private',
  },
  'x-pack/solutions/search/plugins': {
    group: 'search',
    visibility: 'private',
  },
```

* If a plugin is moved to one of the specific locations above, the group
and visibility in the manifest (if specified) must match those inferred
from the path.
* Plugins that are not relocated are considered: `group: 'common',
visibility: 'shared'` by default. As soon as we specify a custom
`group`, the ESLINT rules will check violations against dependencies /
dependants.

The ESLINT rules are pretty simple:
* Plugins can only depend on:
  * Plugins in the same group
  * OR plugins with `'shared'` visibility
* Plugins in `'observability', 'security', 'search'` groups are
mandatorily `'private'`.

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

packages/kbn-repo-source-classifier/src/group.ts

@@ -0,0 +1,63 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import type { ModuleGroup, ModuleVisibility } from '@kbn/repo-info/types';
+
+interface ModuleAttrs {
+  group: ModuleGroup;
+  visibility: ModuleVisibility;
+}
+
+const DEFAULT_MODULE_ATTRS: ModuleAttrs = {
+  group: 'common',
+  visibility: 'shared',
+};
+
+const MODULE_GROUPING_BY_PATH: Record<string, ModuleAttrs> = {
+  'src/platform/plugins/shared': {
+    group: 'platform',
+    visibility: 'shared',
+  },
+  'src/platform/plugins/internal': {
+    group: 'platform',
+    visibility: 'private',
+  },
+  'x-pack/platform/plugins/shared': {
+    group: 'platform',
+    visibility: 'shared',
+  },
+  'x-pack/platform/plugins/internal': {
+    group: 'platform',
+    visibility: 'private',
+  },
+  'x-pack/solutions/observability/plugins': {
+    group: 'observability',
+    visibility: 'private',
+  },
+  'x-pack/solutions/security/plugins': {
+    group: 'security',
+    visibility: 'private',
+  },
+  'x-pack/solutions/search/plugins': {
+    group: 'search',
+    visibility: 'private',
+  },
+};
+
+/**
+ * Determine a plugin's grouping information based on the path where it is defined
+ * @param packageRelativePath the path in the repo where the package is located
+ * @returns The grouping information that corresponds to the given path
+ */
+export function inferGroupAttrsFromPath(packageRelativePath: string): ModuleAttrs {
+  const grouping = Object.entries(MODULE_GROUPING_BY_PATH).find(([chunk]) =>
+    packageRelativePath.startsWith(chunk)
+  )?.[1];
+  return grouping ?? DEFAULT_MODULE_ATTRS;
+}

packages/kbn-repo-source-classifier/src/module_id.ts

@@ -7,16 +7,24 @@
  * License v3.0 only", or the "Server Side Public License, v 1".
  */
 
-import { ModuleType } from './module_type';
-import { PkgInfo } from './pkg_info';
+import type { KibanaPackageManifest } from '@kbn/repo-packages';
+import type { ModuleGroup, ModuleVisibility } from '@kbn/repo-info/types';
+import type { ModuleType } from './module_type';
+import type { PkgInfo } from './pkg_info';
 
 export interface ModuleId {
   /** Type of the module */
   type: ModuleType;
+  /** Specifies the group to which this module belongs */
+  group: ModuleGroup;
+  /** Specifies the module visibility, i.e. whether it can be accessed by everybody or only modules in the same group */
+  visibility: ModuleVisibility;
   /** repo relative path to the module's source file */
   repoRel: string;
   /** info about the package the source file is within, in the case the file is found within a package */
   pkgInfo?: PkgInfo;
+  /** The type of package, as described in the manifest */
+  manifest?: KibanaPackageManifest;
   /** path segments of the dirname of this */
   dirs: string[];
 }

packages/kbn-repo-source-classifier/src/repo_source_classifier.ts

@@ -7,11 +7,14 @@
  * License v3.0 only", or the "Server Side Public License, v 1".
  */
 
-import { ImportResolver } from '@kbn/import-resolver';
-import { ModuleId } from './module_id';
-import { ModuleType } from './module_type';
+import type { ImportResolver } from '@kbn/import-resolver';
+import type { ModuleGroup, ModuleVisibility } from '@kbn/repo-info/types';
+import type { KibanaPackageManifest } from '@kbn/repo-packages/modern/types';
+import type { ModuleId } from './module_id';
+import type { ModuleType } from './module_type';
 import { RANDOM_TEST_FILE_NAMES, TEST_DIR, TEST_TAG } from './config';
 import { RepoPath } from './repo_path';
+import { inferGroupAttrsFromPath } from './group';
 
 const STATIC_EXTS = new Set(
   'json|woff|woff2|ttf|eot|svg|ico|png|jpg|gif|jpeg|html|md|txt|tmpl|xml'
@@ -231,7 +234,43 @@ export class RepoSourceClassifier {
     return 'common package';
   }
 
-  classify(absolute: string) {
+  private getManifest(path: RepoPath): KibanaPackageManifest | undefined {
+    const pkgInfo = path.getPkgInfo();
+    return pkgInfo?.pkgId ? this.resolver.getPkgManifest(pkgInfo!.pkgId) : undefined;
+  }
+  /**
+   * Determine the "group" of a file
+   */
+  private getGroup(path: RepoPath): ModuleGroup {
+    const attrs = inferGroupAttrsFromPath(path.getRepoRel());
+    const manifest = this.getManifest(path);
+
+    if (attrs.group !== 'common') {
+      // this package has been moved to a 'group-specific' folder, the group is determined by its location
+      return attrs.group;
+    } else {
+      // the package is still in its original location, allow Manifest to dictate its group
+      return manifest?.group ?? 'common';
+    }
+  }
+
+  /**
+   * Determine the "visibility" of a file
+   */
+  private getVisibility(path: RepoPath): ModuleVisibility {
+    const attrs = inferGroupAttrsFromPath(path.getRepoRel());
+    const manifest = this.getManifest(path);
+
+    if (attrs.group !== 'common') {
+      // this package has been moved to a 'group-specific' folder, the visibility is determined by its location
+      return attrs.visibility;
+    } else {
+      // the package is still in its original location, allow Manifest to dictate its visibility
+      return manifest?.visibility ?? 'shared';
+    }
+  }
+
+  classify(absolute: string): ModuleId {
     const path = this.getRepoPath(absolute);
     const cached = this.ids.get(path);
 
@@ -241,8 +280,12 @@ export class RepoSourceClassifier {
 
     const id: ModuleId = {
       type: this.getType(path),
+      group: this.getGroup(path),
+      visibility: this.getVisibility(path),
       repoRel: path.getRepoRel(),
       pkgInfo: path.getPkgInfo() ?? undefined,
+      manifest:
+        (path.getPkgInfo() && this.resolver.getPkgManifest(path.getPkgInfo()!.pkgId)) ?? undefined,
       dirs: path.getSegs(),
     };
     this.ids.set(path, id);

packages/kbn-repo-source-classifier/tsconfig.json

@@ -13,6 +13,7 @@
   "kbn_references": [
     "@kbn/import-resolver",
     "@kbn/repo-info",
+    "@kbn/repo-packages",
   ],
   "exclude": [
     "target/**/*",