delete sections if duplicate bug occurs

Author: frankh

cmd/updater/main.go

@@ -67,14 +67,34 @@ func main() {
 		log.Fatalf("Failed to get file info: %v", err)
 	}
 
+	// there is a bug where occasionally replacing the entire canvas doesn't work and we end up with multiple
+	// images in the canvas. This is a workaround to delete all existing sections and replace the entire canvas.
+	sections, err := api.LookupCanvasSections(slack.LookupCanvasSectionsParams{
+		CanvasID: canvasId,
+	})
+	if err != nil {
+		log.Fatalf("Failed to get canvas sections: %v", err)
+	}
+
+	var changes []slack.CanvasChange
+
+	if len(sections) > 1 {
+		log.Printf("Detected multiple sections in canvas, deleting all sections")
+		for _, section := range sections {
+			changes = append(changes, slack.CanvasChange{
+				Operation: "delete",
+				SectionID: section.ID,
+			})
+		}
+	}
+
 	// edit canvas
 	err = api.EditCanvas(slack.EditCanvasParams{
 		CanvasID: canvasId,
-		Changes: []slack.CanvasChange{
-			{
-				Operation: "replace",
-				SectionID: canvasSectionId,  // ok if this is empty string, will replace the entire canvas
-				DocumentContent: slack.DocumentContent{
+		Changes: append(changes, slack.CanvasChange{
+			Operation: "replace",
+			SectionID: canvasSectionId,  // ok if this is empty string, will replace the entire canvas
+			DocumentContent: slack.DocumentContent{
 					Type: "markdown",
 					Markdown: fmt.Sprintf(`
 ### Overview
@@ -83,9 +103,8 @@ func main() {
 
 ---
 `, fileSummary.ID, fileInfo.Permalink),
-				},
 			},
-		},
+		}),
 	})
 	if err != nil {
 		log.Fatalf("Failed to edit canvas: %v", err)