cmd/release: don't read pr-body file in post-release step

cmd/release/post-release_pull_request.go

@@ -60,27 +60,14 @@ func (pc *PustPostPullRequest) Run(ctx context.Context, yesToPrompt, dryRun bool
 	majorMinor := semver.MajorMinor(pc.cfg.TargetVer)
 	isMinorRelease := strings.TrimPrefix(pc.cfg.TargetVer, majorMinor) == ".0"
 	if isMinorRelease {
+		// The full changelog of a minor release would exceed the maximum size
+		// of a GitHub release body, so use the same short body as the
+		// "Prepare for release" PR and leave it up to the maintainers to
+		// replace it with the release announcement.
 		const instructionMsg = "<!-- Copy the slack announcement message to here and adapt emojis -->\n\n"
-		if _, err := releaseSummaryFileContent.WriteString(instructionMsg); err != nil {
+		if _, err := releaseSummaryFileContent.WriteString(instructionMsg + prBodyMsg); err != nil {
 			return fmt.Errorf("unable to write instruction message to release summary file: %w", err)
 		}
-
-		// For minor releases, use the -pr-body.txt file
-		prBodyFileName := fmt.Sprintf("%s-pr-body.txt", pc.cfg.TargetVer)
-		prBodyFile := filepath.Join(pc.cfg.RepoDirectory, prBodyFileName)
-		prBodyFileContent, err := os.Open(prBodyFile)
-		if err != nil {
-			if !os.IsNotExist(err) {
-				return fmt.Errorf("error reading %s file: %w", prBodyFileName, err)
-			} else {
-				return fmt.Errorf("%s file not found, it needs to be present to create a release on GitHub for minor releases", prBodyFileName)
-			}
-		}
-		defer prBodyFileContent.Close()
-
-		if _, err := io.Copy(releaseSummaryFileContent, prBodyFileContent); err != nil {
-			return fmt.Errorf("unable to copy the pr-body file content into the release summary file: %w", err)
-		}
 	} else {
 		// Generate release summary
 		changelogFile := filepath.Join(pc.cfg.RepoDirectory, "CHANGELOG.md")

cmd/release/pull_request.go

@@ -16,6 +16,11 @@ import (
 	github2 "github.com/google/go-github/v62/github"
 )
 
+// prBodyMsg is the body used for the "Prepare for release" PR. It is also
+// re-used as the body of the draft GitHub release for minor releases, since
+// the full changelog would exceed the maximum size of a release body.
+const prBodyMsg = "\nSee the included CHANGELOG.md for a full list of changes.\n"
+
 type PushPullRequest struct {
 	cfg *ReleaseConfig
 }
@@ -144,7 +149,7 @@ func (pc *PushPullRequest) generateSummaryFile() (string, string, error) {
 	}
 	defer prBodyFileContent.Close()
 
-	prBodyFileContent.WriteString("\nSee the included CHANGELOG.md for a full list of changes.\n")
+	prBodyFileContent.WriteString(prBodyMsg)
 
 	return prTitle, prBodyFileName, err
 }