feat(dashboard): show deprecated dependency warnings

docs/usage/key-concepts/dashboard.md

@@ -49,6 +49,24 @@
 
 This section explains some common use cases where having the Dependency Dashboard can help.
 
+### Warnings for deprecated dependencies
+
+If Renovate finds: 
+
+- packages flagged as deprecated on their registry, or
+- packages that have a community-sourced replacement PR available
+
+Then Renovate adds a prominent warning about these packages near the top of the Dependency Dashboard.
+Here is an example of how this can look:
+
+> [!WARNING]
+> The following dependencies are deprecated:
+
+| Datasource | Name                | Replacement?                                                                      |
+| ---------- | ------------------- | --------------------------------------------------------------------------------- |
+| npm        | `airbnb-prop-types` | ![Available](https://img.shields.io/badge/available-green?style=flat-square)      |
+| npm        | `left-pad`          | ![Unavailable](https://img.shields.io/badge/unavailable-orange?style=flat-square) |
+
 ### Visibility into rejected/deferred updates
 
 Renovate's Dependency Dashboard shows an overview of all updates that are still "to do".

lib/workers/repository/dependency-dashboard.spec.ts

@@ -19,6 +19,7 @@ import {
   GitHubMaxPrBodyLen,
   massageMarkdown,
 } from '../../modules/platform/github';
+import { clone } from '../../util/clone';
 import { regEx } from '../../util/regex';
 import type { BranchConfig, BranchUpgradeConfig } from '../types';
 import * as dependencyDashboard from './dependency-dashboard';
@@ -981,6 +982,37 @@ None detected
           // same with dry run
           await dryRun(branches, platform, 0, 1);
         });
+
+        it('shows deprecations', async () => {
+          const branches: BranchConfig[] = [];
+          const packageFilesWithDeprecations = clone(packageFiles);
+          packageFilesWithDeprecations.npm[0].deps[0].deprecationMessage =
+            'some deprecation message';
+          packageFilesWithDeprecations.npm[0].deps[2].updates.push({
+            updateType: 'replacement',
+            newName: 'prop-types-tools',
+            newValue: '2.17.0',
+            branchName: 'renovate/airbnb-prop-types-replacement',
+          });
+          PackageFiles.add('main', packageFilesWithDeprecations);
+          await dependencyDashboard.ensureDependencyDashboard(
+            config,
+            branches,
+            packageFilesWithDeprecations,
+          );
+          expect(platform.ensureIssue).toHaveBeenCalledTimes(1);
+          expect(platform.ensureIssue.mock.calls[0][0].body).toInclude(
+            'The following dependencies are deprecated',
+          );
+          expect(platform.ensureIssue.mock.calls[0][0].body).toInclude(
+            '| npm | `cookie-parser` | ![Unavailable]',
+          );
+          expect(platform.ensureIssue.mock.calls[0][0].body).toInclude(
+            'npm | `express-handlebars` | ![Available]',
+          );
+          // same with dry run
+          await dryRun(branches, platform, 0, 1);
+        });
       });
 
       describe('multi base branch repo', () => {

lib/workers/repository/dependency-dashboard.ts

@@ -224,8 +224,29 @@ export async function ensureDependencyDashboard(
     return;
   }
   logger.debug('Ensuring Dependency Dashboard');
+
+  // Check packageFiles for any deprecations
+  let hasDeprecations = false;
+  const deprecatedPackages: Record<string, Record<string, boolean>> = {};
+  logger.debug({ packageFiles }, 'Checking packageFiles for deprecations');
+  for (const [manager, fileNames] of Object.entries(packageFiles)) {
+    for (const fileName of fileNames) {
+      for (const dep of fileName.deps) {
+        const name = dep.packageName ?? dep.depName;
+        const hasReplacement = !!dep.updates?.find(
+          (updates) => updates.updateType === 'replacement',
+        );
+        if (name && (dep.deprecationMessage ?? hasReplacement)) {
+          hasDeprecations = true;
+          deprecatedPackages[manager] ??= {};
+          deprecatedPackages[manager][name] ??= hasReplacement;
+        }
+      }
+    }
+  }
+
   const hasBranches = is.nonEmptyArray(branches);
-  if (config.dependencyDashboardAutoclose && !hasBranches) {
+  if (config.dependencyDashboardAutoclose && !hasBranches && !hasDeprecations) {
     if (GlobalConfig.get('dryRun')) {
       logger.info(
         { title: config.dependencyDashboardTitle },
@@ -245,6 +266,25 @@ export async function ensureDependencyDashboard(
 
   issueBody = appendRepoProblems(config, issueBody);
 
+  if (hasDeprecations) {
+    issueBody += '> ⚠ **Warning**\n> \n';
+    issueBody += 'The following dependencies are deprecated:\n\n';
+    issueBody += '| Datasource | Name | Replacement PR? |\n';
+    issueBody += '|------------|------|--------------|\n';
+    for (const manager of Object.keys(deprecatedPackages).sort()) {
+      const deps = deprecatedPackages[manager];
+      for (const depName of Object.keys(deps).sort()) {
+        const hasReplacement = deps[depName];
+        issueBody += `| ${manager} | \`${depName}\` | ${
+          hasReplacement
+            ? '![Available](https://img.shields.io/badge/available-green?style=flat-square)'
+            : '![Unavailable](https://img.shields.io/badge/unavailable-orange?style=flat-square)'
+        } |\n`;
+      }
+    }
+    issueBody += '\n';
+  }
+
   const pendingApprovals = branches.filter(
     (branch) => branch.result === 'needs-approval',
   );