fix(validation): validate installTools (#42838)

* test(validation): validate `installTools` aren't validated

Co-authored-by: Claude Sonnet 4.6 <jamie.tanna+claude-code@mend.io>

* fix(validation): validate `installTools`

As we have a strong type for our `ToolName`s, we should make sure that
we now validate the `installTools`.

We'll start with a warning for now, and at some point promote it to an
error in the future.

Co-authored-by: Claude Sonnet 4.6 <jamie.tanna+claude-code@mend.io>

---------

Co-authored-by: Claude Sonnet 4.6 <jamie.tanna+claude-code@mend.io>

Author: jamietanna

lib/config/validation.spec.ts

@@ -2352,6 +2352,48 @@ describe('config/validation', () => {
       );
     });
 
+    it('validates postUpgradeTasks.installTools tool names', async () => {
+      const config = {
+        postUpgradeTasks: {
+          executionMode: 'update' as const,
+          installTools: {
+            npm: {},
+            node: {},
+          },
+        },
+      };
+      const { warnings, errors } = await configValidation.validateConfig(
+        'global',
+        config,
+      );
+      expect(warnings).toHaveLength(0);
+      expect(errors).toHaveLength(0);
+    });
+
+    it('rejects invalid postUpgradeTasks.installTools tool names', async () => {
+      const config = {
+        postUpgradeTasks: {
+          installTools: {
+            npm: {},
+            unknownTool: {},
+          },
+        },
+      };
+      const { warnings, errors } = await configValidation.validateConfig(
+        'global',
+        // @ts-expect-error: installTools.unknownTool is not a valid tool
+        config,
+      );
+      expect(warnings).toMatchObject([
+        {
+          topic: 'Configuration Error',
+          message:
+            'Invalid `postUpgradeTasks.installTools.unknownTool` configuration: not a valid tool name.',
+        },
+      ]);
+      expect(errors).toHaveLength(0);
+    });
+
     it('catches when * or ** is combined with others patterns in a regexOrGlob option', async () => {
       const config = {
         packageRules: [

lib/config/validation.ts

@@ -13,6 +13,7 @@ import { isCustomManager } from '../modules/manager/custom/index.ts';
 import type { CustomManager } from '../modules/manager/custom/types.ts';
 import { allManagersList, getManagerList } from '../modules/manager/index.ts';
 import type { HostRule } from '../types/index.ts';
+import { isToolName } from '../util/exec/types.ts';
 import { getExpression } from '../util/jsonata.ts';
 import { regEx } from '../util/regex.ts';
 import {
@@ -751,6 +752,15 @@ export async function validateConfig(
                   }
                 }
               }
+            } else if (key === 'installTools') {
+              for (const toolName of Object.keys(val)) {
+                if (!isToolName(toolName)) {
+                  warnings.push({
+                    topic: 'Configuration Error',
+                    message: `Invalid \`${currentPath}.${toolName}\` configuration: not a valid tool name.`,
+                  });
+                }
+              }
             } else {
               const ignoredObjects = options
                 .filter((option) => option.freeChoice)