closePR: rename to closePRAsMerged with a celebratory message

Rename `closePR()` to `closePRAsMerged()` and the local variable
`closePR` to `upstreamMergeCommit` to clarify that closing a PR
in this context is a positive event: the patch series was merged
upstream.

Update the comment posted on the PR to congratulate the contributor
and explain why the GitHub PR shows as "Closed" rather than "Merged"
(because the merge happened in the upstream repo, not on GitHub).

Author: HaraldNordgren

lib/ci-helper.ts

@@ -647,7 +647,7 @@ export class CIHelper {
             }
         }
 
-        let closePR: string | undefined;
+        let upstreamMergeCommit: string | undefined;
         const prLabelsToAdd: string[] = [];
         for (const branch of this.config.repo.trackingBranches) {
             const mergeCommit = await this.identifyMergeCommit(branch, tipCommitInGitGit);
@@ -656,7 +656,7 @@ export class CIHelper {
             }
 
             if (this.config.repo.closingBranches.includes(branch)) {
-                closePR = mergeCommit;
+                upstreamMergeCommit = mergeCommit;
             }
 
             if (!prMeta.mergedIntoUpstream) {
@@ -683,7 +683,7 @@ export class CIHelper {
         }
 
         let optionsUpdated = false;
-        if (closePR) {
+        if (upstreamMergeCommit) {
             if (options.openPRs) {
                 delete options.openPRs[pullRequestURL];
                 optionsUpdated = true;
@@ -697,7 +697,7 @@ export class CIHelper {
                 optionsUpdated = true;
             }
 
-            await this.github.closePR(prKey, closePR);
+            await this.github.closePRAsMerged(prKey, upstreamMergeCommit);
         }
 
         if (notesUpdated) {

lib/github-glue.ts

@@ -289,7 +289,7 @@ export class GitHubGlue {
         return result.data.map((res: { id: number }) => `${res.id}`);
     }
 
-    public async closePR(pullRequest: pullRequestKeyInfo, viaMergeCommit: string): Promise<number> {
+    public async closePRAsMerged(pullRequest: pullRequestKeyInfo, mergeCommit: string): Promise<number> {
         const prKey = getPullRequestKey(pullRequest);
 
         await this.ensureAuthenticated(prKey.owner);
@@ -298,8 +298,16 @@ export class GitHubGlue {
             ...prKey,
         });
 
+        const body =
+            "Congratulations! 🎉 Your patch series was merged" +
+            ` into upstream via ${mergeCommit}.\n\n` +
+            "Note: this pull request will show as" +
+            ' "Closed" rather than "Merged" because the' +
+            " merge happened in the upstream repository," +
+            " not on GitHub. This is expected —" +
+            " your contribution has been accepted!";
         const result = await this.client.rest.issues.createComment({
-            body: `Closed via ${viaMergeCommit}.`,
+            body,
             issue_number: prKey.pull_number,
             owner: prKey.owner,
             repo: prKey.repo,

tests/github-glue.test.ts

@@ -99,7 +99,7 @@ test("pull requests", async () => {
             });
 
             if (pullRequestURL.length) {
-                await github.closePR(pullRequestURL, "Not merged");
+                await github.closePRAsMerged(pullRequestURL, "Not merged");
             }
 
             try {
@@ -212,7 +212,7 @@ test("pull requests", async () => {
 
         await github.addPRLabels(prData.html_url, ["bug"]);
 
-        const cNumber = await github.closePR(prData.html_url, "Not merged");
+        const cNumber = await github.closePRAsMerged(prData.html_url, "Not merged");
         expect(cNumber).toBeGreaterThan(id);
 
         // delete local and remote branches