[ts/checkProjects] validate extends of all ts projects (#145176)

Fixes https://github.com/elastic/kibana/issues/145129

In order to make our TS setup in the repo far more efficient we needed
to make it a little more complicated than it used to be. This includes a
few rules that all tsconfig files need to follow which were currently
assumed to be true, but with this PR will now be validated:

1. No tsconfig.json files are allowed to extend the `tsconfig.json`
file. This file is used to produce types for the root of the repo, and
include the `package.json` file in a project so it can be referenced in
projects directly. Files which violate this rule were updated to point
to the root `tsconfig.base.json` file.
2. Every tsconfig.json file must extend the `tsconfig.base.json` file,
either directly or indirectly.

examples/field_formats_example/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.json",
+  "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./target",
     "skipLibCheck": true

examples/files_example/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.json",
+  "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./target/types"
   },

examples/hello_world/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.json",
+  "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./target/types"
   },

examples/partial_results_example/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.json",
+  "extends": "../../tsconfig.base.json",
   "compilerOptions": {
     "outDir": "./target",
     "skipLibCheck": true

src/dev/typescript/project.ts

@@ -174,4 +174,8 @@ export class Project {
       ? [this.tsConfigPath, ...this.baseProject.getConfigPaths()]
       : [this.tsConfigPath];
   }
+
+  public getProjectsDeep(): Project[] {
+    return this.baseProject ? [this, ...this.baseProject.getProjectsDeep()] : [this];
+  }
 }

src/dev/typescript/run_check_ts_projects_cli.ts

@@ -12,6 +12,7 @@ import { run } from '@kbn/dev-cli-runner';
 import { asyncMapWithLimit } from '@kbn/std';
 import { createFailError } from '@kbn/dev-cli-errors';
 import { getRepoFiles } from '@kbn/get-repo-files';
+import { REPO_ROOT } from '@kbn/utils';
 import globby from 'globby';
 
 import { File } from '../file';
@@ -37,6 +38,25 @@ export async function runCheckTsProjectsCli() {
       const stats = new Stats();
       let failed = false;
 
+      const everyProjectDeep = new Set(PROJECTS.flatMap((p) => p.getProjectsDeep()));
+      for (const proj of everyProjectDeep) {
+        const [, ...baseConfigRels] = proj.getConfigPaths().map((p) => Path.relative(REPO_ROOT, p));
+        const configRel = Path.relative(REPO_ROOT, proj.tsConfigPath);
+
+        if (baseConfigRels[0] === 'tsconfig.json') {
+          failed = true;
+          log.error(
+            `[${configRel}]: This tsconfig extends the root tsconfig.json file and shouldn't. The root tsconfig.json file is not a valid base config, you probably want to point to the tsconfig.base.json file.`
+          );
+        }
+        if (configRel !== 'tsconfig.base.json' && !baseConfigRels.includes('tsconfig.base.json')) {
+          failed = true;
+          log.error(
+            `[${configRel}]: This tsconfig does not extend the tsconfig.base.json file either directly or indirectly. The TS config setup for the repo expects every tsconfig file to extend this base config file.`
+          );
+        }
+      }
+
       const pathsAndProjects = await asyncMapWithLimit(PROJECTS, 5, async (proj) => {
         const paths = await globby(proj.getIncludePatterns(), {
           ignore: proj.getExcludePatterns(),