fix(platform): trim labels

docs/usage/configuration-options.md

@@ -79,6 +79,11 @@ With the above config:
 - ESLint dependencies will have the label `linting`
 - All other dependencies will have the label `dependencies`
 
+<!-- prettier-ignore -->
+!!! note
+    Keep your labels within the maximum character limit for your Git hosting platform.
+    Renovate usually truncates labels to 50 characters, except for GitLab, which has a 255 character limit.
+
 ## additionalBranchPrefix
 
 By default, the value for this config option is an empty string.
@@ -2200,6 +2205,11 @@ Behavior details:
 The `labels` array is non-mergeable, meaning if multiple `packageRules` match then Renovate uses the last value for `labels`.
 If you want to add/combine labels, use the `addLabels` config option, which is mergeable.
 
+<!-- prettier-ignore -->
+!!! note
+    Keep your labels within the maximum character limit for your Git hosting platform.
+    Renovate usually truncates labels to 50 characters, except for GitLab, which has a 255 character limit.
+
 ## lockFileMaintenance
 
 You can use `lockFileMaintenance` to refresh lock files to keep them up-to-date.

lib/modules/platform/gitlab/index.ts

@@ -92,6 +92,7 @@ const defaults = {
 };
 
 export const id = 'gitlab';
+export const labelCharLimit = 255;
 
 const DRAFT_PREFIX = 'Draft: ';
 const DRAFT_PREFIX_DEPRECATED = 'WIP: ';

lib/modules/platform/types.ts

@@ -280,6 +280,7 @@ export interface Platform {
   expandGroupMembers?(reviewersOrAssignees: string[]): Promise<string[]>;
 
   maxBodyLength(): number;
+  labelCharLimit?: number;
 }
 
 export interface PlatformScm {

lib/workers/repository/update/pr/labels.spec.ts

@@ -1,3 +1,4 @@
+import { platform } from '../../../../../test/util';
 import {
   areLabelsModified,
   getChangedLabels,
@@ -6,6 +7,10 @@ import {
 } from './labels';
 
 describe('workers/repository/update/pr/labels', () => {
+  beforeEach(() => {
+    platform.labelCharLimit = 50;
+  });
+
   describe('prepareLabels(config)', () => {
     it('returns empty array if no labels are configured', () => {
       const result = prepareLabels({});
@@ -82,6 +87,42 @@ describe('workers/repository/update/pr/labels', () => {
       expect(result).toBeArrayOfSize(0);
       expect(result).toEqual([]);
     });
+
+    describe('trim labels that go over the max char limit', () => {
+      const labels = [
+        'All',
+        'The quick brown fox jumped over the lazy sleeping dog', // len: 51
+        // len: 256
+        'Torem ipsum dolor sit amet, consectetur adipiscing elit. Sed fringilla erat eu lectus gravida varius. Maecenas suscipit risus nec erat mollis tempus. Vestibulum cursus urna et faucibus tempor. Nam eleifend libero in enim sodales, eu placerat enim dice rep!',
+      ];
+
+      it('github', () => {
+        platform.labelCharLimit = undefined as never; // coverage
+        expect(prepareLabels({ labels })).toEqual([
+          'All',
+          'The quick brown fox jumped over the lazy sleeping', // len: 50
+          'Torem ipsum dolor sit amet, consectetur adipiscing', // len: 50
+        ]);
+      });
+
+      it('gitlab', () => {
+        platform.labelCharLimit = 255;
+        expect(prepareLabels({ labels })).toEqual([
+          'All',
+          'The quick brown fox jumped over the lazy sleeping dog', // len: 51
+          // len: 255
+          'Torem ipsum dolor sit amet, consectetur adipiscing elit. Sed fringilla erat eu lectus gravida varius. Maecenas suscipit risus nec erat mollis tempus. Vestibulum cursus urna et faucibus tempor. Nam eleifend libero in enim sodales, eu placerat enim dice rep',
+        ]);
+      });
+
+      it('gitea', () => {
+        expect(prepareLabels({ labels })).toEqual([
+          'All',
+          'The quick brown fox jumped over the lazy sleeping', // len: 50
+          'Torem ipsum dolor sit amet, consectetur adipiscing', // len: 50
+        ]);
+      });
+    });
   });
 
   describe('getChangedLabels', () => {

lib/workers/repository/update/pr/labels.ts

@@ -2,15 +2,29 @@ import is from '@sindresorhus/is';
 import { dequal } from 'dequal';
 import type { RenovateConfig } from '../../../../config/types';
 import { logger } from '../../../../logger';
+import { platform } from '../../../../modules/platform';
 import * as template from '../../../../util/template';
 
+/**
+ * Filter labels that go over the maximum char limit, based on platform limits.
+ */
+function trimLabel(label: string, limit: number): string {
+  if (label.length > limit) {
+    return label.trim().slice(0, limit).trim();
+  }
+
+  return label.trim();
+}
+
 export function prepareLabels(config: RenovateConfig): string[] {
+  const labelCharLimit = platform.labelCharLimit ?? 50;
   const labels = config.labels ?? [];
   const addLabels = config.addLabels ?? [];
   return [...new Set([...labels, ...addLabels])]
     .filter(is.nonEmptyStringAndNotWhitespace)
     .map((label) => template.compile(label, config))
     .filter(is.nonEmptyStringAndNotWhitespace)
+    .map((label) => trimLabel(label, labelCharLimit))
     .sort();
 }