add ability to update PR by adding a label (#102)

This feature allows a maintainer to update a PR's branch by adding the `giteabot/update-branch` label. It is being removed after the update.

Co-authored-by: silverwind <[email protected]>

README.md

@@ -62,6 +62,11 @@ The script will also lock issues and pull requests that have been closed for 3
 months. If the issue was commented on in the last two weeks, a comment will be
 posted suggesting opening a new issue to continue the discussion.
 
+### Maintainer commands
+
+The script can execute some actions like updating a PR's branch if requested by
+a maintainer through a `giteabot/*` label.
+
 ## Usage
 
 Set the following environment variables:

src/labels.ts

@@ -12,7 +12,8 @@ import { debounce } from "https://deno.land/[email protected]/async/mod.ts";
 // manage backports or any other label that causes the bot to act on
 // detection, such as reviewed/* or backport/*
 export const isRelevantLabel = (label: string): boolean => {
-  return label.startsWith("reviewed/") || label.startsWith("backport/");
+  return label.startsWith("reviewed/") || label.startsWith("backport/") ||
+    label.startsWith("giteabot/");
 };
 
 const maintain = async () => {

src/mergeQueue.ts

@@ -1,10 +1,5 @@
-import {
-  addComment,
-  fetchPendingMerge,
-  needsUpdate,
-  removeLabel,
-  updatePr,
-} from "./github.ts";
+import { fetchPendingMerge, removeLabel } from "./github.ts";
+import * as prActions from "./prActions.ts";
 import { debounce } from "https://deno.land/[email protected]/async/mod.ts";
 
 const updateBranch = async () => {
@@ -13,31 +8,12 @@ const updateBranch = async () => {
 
   // update all PRs pending merge (only if they need an update)
   for (const pr of pendingMerge.items) {
-    if (!await needsUpdate(pr.number)) continue;
-    const response = await updatePr(pr.number);
-    if (response.ok) {
-      console.info(`Synced PR #${pr.number} in merge queue`);
-      continue;
-    }
+    const err = await prActions.updateBranch(pr);
 
-    const body = await response.json();
-    if (body.message !== "merge conflict between base and head") {
-      console.error(`Failed to sync PR #${pr.number} in merge queue`);
-      console.error(JSON.stringify(body));
-      continue;
+    if (err?.message == "merge conflicts in PR") {
+      // if there is a merge conflict, we'll remove the reviewed/wait-merge label
+      await removeLabel(pr.number, "reviewed/wait-merge");
     }
-
-    console.info(
-      `Merge conflict detected in PR #${pr.number} in merge queue`,
-    );
-    // if there is a merge conflict, we'll add a comment to fix the conflicts and remove the reviewed/wait-merge label
-    await Promise.all([
-      addComment(
-        pr.number,
-        `@${pr.user.login} please fix the merge conflicts. :tea:`,
-      ),
-      removeLabel(pr.number, "reviewed/wait-merge"),
-    ]);
   }
 };
 

src/prActions.ts

@@ -0,0 +1,45 @@
+import { addComment, needsUpdate, removeLabel, updatePr } from "./github.ts";
+import { debounce } from "https://deno.land/[email protected]/async/mod.ts";
+
+const execute = async (
+  label: string,
+  pr: { number: number; user: { login: string } },
+) => {
+  if (label === "giteabot/update-branch") {
+    await updateBranch(pr);
+    await removeLabel(pr.number, "giteabot/update-branch");
+  }
+};
+
+export const updateBranch = async (
+  pr: { number: number; user: { login: string } },
+) => {
+  if (await needsUpdate(pr.number)) {
+    const response = await updatePr(pr.number);
+    if (response.ok) {
+      console.info(`Synced PR #${pr.number}`);
+      return;
+    }
+
+    const body = await response.json();
+    if (body.message !== "merge conflict between base and head") {
+      console.error(
+        `Failed to sync PR #${pr.number}`,
+      );
+      console.error(JSON.stringify(body));
+    }
+
+    console.info(
+      `Merge conflict detected in PR #${pr.number}`,
+    );
+    // if there is a merge conflict, we'll add a comment to fix the conflicts
+    await addComment(
+      pr.number,
+      `@${pr.user.login} please fix the merge conflicts. :tea:`,
+    );
+    return Error("merge conflicts in PR");
+  }
+};
+
+// make sure we don't trigger too often
+export const run = debounce(execute, 8000);

src/webhook.ts

@@ -8,6 +8,7 @@ import * as milestones from "./milestones.ts";
 import * as lgtm from "./lgtm.ts";
 import * as comments from "./comments.ts";
 import * as lock from "./lock.ts";
+import * as prActions from "./prActions.ts";
 
 const secret = Deno.env.get("BACKPORTER_GITHUB_SECRET");
 
@@ -45,6 +46,7 @@ webhook.on(
     if (labels.isRelevantLabel(payload.label.name)) {
       labels.run();
       mergeQueue.run();
+      prActions.run(payload.label.name, payload.pull_request);
     }
   },
 );