feat: add support for controlling whether PRs can be edited by mainta…

…iners

Platforms like GitHub, or Gitlab supports options to control whether
a PR can be modified by maintainers.

See e.g. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork

This commit introduces a way to control this in Renovate. The option
will default to `true`.

docs/usage/configuration-options.md

@@ -2181,6 +2181,18 @@ Defaults to `update`, but can also be set to `branch`.
 This sets the level the postUpgradeTask runs on, if set to `update` the postUpgradeTask will be executed for every dependency on the branch.
 If set to `branch` the postUpgradeTask is executed for the whole branch.
 
+## prAllowMaintainerEdits
+
+This setting controls whether pull requests created by Renovate will allow edits by maintainers.
+
+When Renovate operates in a fork, this allows project maintainers to make manual changes
+to the Renovate PR branch— without needing to create another new PR.
+
+<!-- prettier-ignore -->
+!!! note
+    If Renovate does not operate in a fork, maintainers can make modifications regardless
+    as they have access to upstream branches.
+
 ## prBodyColumns
 
 Use this array to provide a list of column names you wish to include in the PR tables.

lib/config/options/index.ts

@@ -1555,6 +1555,14 @@ const options: RenovateOptions[] = [
     allowedValues: ['strict', 'flexible', 'none'],
     default: 'strict',
   },
+  {
+    name: 'prAllowMaintainerEdits',
+    description:
+      'Whether pull requests created should allow for maintainer edits.',
+    type: 'boolean',
+    supportedPlatforms: ['github', 'gitlab'],
+    default: true,
+  },
   {
     name: 'prCreation',
     description: 'When to create the PR for a branch.',

lib/config/types.ts

@@ -230,6 +230,7 @@ export interface RenovateConfig
   postUpdateOptions?: string[];
   prConcurrentLimit?: number;
   prHourlyLimit?: number;
+  prAllowMaintainerEdits?: boolean;
 
   defaultRegistryUrls?: string[];
   registryUrls?: string[] | null;

lib/modules/platform/types.ts

@@ -103,6 +103,7 @@ export interface CreatePRConfig {
   labels?: string[] | null;
   platformOptions?: PlatformPrOptions;
   draftPR?: boolean;
+  allowMaintainerEdits?: boolean;
 }
 export interface UpdatePrConfig {
   number: number;

lib/workers/repository/config-migration/pr/index.ts

@@ -100,6 +100,7 @@ ${
         sourceBranch: branchName,
         // TODO #7154
         targetBranch: config.defaultBranch!,
+        allowMaintainerEdits: config.prAllowMaintainerEdits,
         prTitle,
         prBody,
         labels,

lib/workers/repository/onboarding/pr/index.ts

@@ -174,6 +174,7 @@ If you need any further assistance then you can also [request help here](${
       const pr = await platform.createPr({
         sourceBranch: config.onboardingBranch!,
         targetBranch: config.defaultBranch!,
+        allowMaintainerEdits: config.prAllowMaintainerEdits,
         prTitle: config.onboardingPrTitle!,
         prBody,
         labels,

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

@@ -353,6 +353,7 @@ export async function ensurePr(
           labels: prepareLabels(config),
           platformOptions: getPlatformPrOptions(config),
           draftPR: config.draftPR,
+          allowMaintainerEdits: config.prAllowMaintainerEdits,
         });
 
         incLimitedValue('PullRequests');