Provisioning: Fix push to PR branch (#103262)

* Fix push to PR branch

* Fix original screenshot generation

pkg/registry/apis/provisioning/jobs/pullrequest/preview.go

@@ -39,13 +39,14 @@ Grafana spotted some changes in your dashboard.
 {{- else if .PreviewScreenshotURL}}
 ### Preview of {{.Filename}}
 ![Preview]({{.PreviewScreenshotURL}})
-{{- end}}
-{{- if and .OriginalURL .PreviewURL}}
-See the [original]({{.OriginalURL}}) and [preview]({{.PreviewURL}}) of {{.Filename}}
+{{ end}}
+
+{{ if and .OriginalURL .PreviewURL}}
+See the [original]({{.OriginalURL}}) and [preview]({{.PreviewURL}}) of {{.Filename}}.
 {{- else if .OriginalURL}}
-See the [original]({{.OriginalURL}}) of {{.Filename}}
+See the [original]({{.OriginalURL}}) of {{.Filename}}.
 {{- else if .PreviewURL}}
-See the [preview]({{.PreviewURL}}) of {{.Filename}}
+See the [preview]({{.PreviewURL}}) of {{.Filename}}.
 {{- end}}`
 
 // PreviewRenderer is an interface for rendering a preview of a file
@@ -160,15 +161,21 @@ func (p *Previewer) Preview(
 			return resourcePreview{}, fmt.Errorf("render dashboard preview: %w", err)
 		}
 		preview.PreviewScreenshotURL = screenshotURL
-		logger.Info("dashboard preview generated", "screenshotURL", screenshotURL)
+		logger.Info("dashboard preview screenshot generated", "screenshotURL", screenshotURL)
 	}
 
 	if preview.OriginalURL != "" {
-		screenshotURL, err := p.renderer.RenderDashboardPreview(ctx, namespace, repoName, f.PreviousPath, base)
+		originalPath := f.PreviousPath
+		if originalPath == "" {
+			originalPath = f.Path
+		}
+
+		screenshotURL, err := p.renderer.RenderDashboardPreview(ctx, namespace, repoName, originalPath, base)
 		if err != nil {
 			return resourcePreview{}, fmt.Errorf("render dashboard preview: %w", err)
 		}
 		preview.OriginalScreenshotURL = screenshotURL
+		logger.Info("original dashboard screenshot generated", "screenshotURL", screenshotURL)
 	}
 
 	return preview, nil

pkg/registry/apis/provisioning/jobs/pullrequest/worker.go

@@ -119,7 +119,13 @@ func (c *PullRequestWorker) Process(ctx context.Context,
 		}
 	}
 
-	preview, err := c.previewer.Preview(ctx, f, job.Namespace, repo.Config().Name, cfg.GitHub.Branch, ref, options.URL, cfg.GitHub.GenerateDashboardPreviews)
+	// Preview should be the branch name if provided, otherwise use the commit hash
+	previewRef := options.Ref
+	if previewRef == "" {
+		previewRef = ref
+	}
+
+	preview, err := c.previewer.Preview(ctx, f, job.Namespace, repo.Config().Name, cfg.GitHub.Branch, previewRef, options.URL, cfg.GitHub.GenerateDashboardPreviews)
 	if err != nil {
 		return fmt.Errorf("generate preview: %w", err)
 	}