fix: address minor issues detected by Go linters

internal/reader/atom/atom_03.go

@@ -116,12 +116,12 @@ type Atom03Content struct {
 func (a *Atom03Content) Content() string {
 	content := ""
 
-	switch {
-	case a.Mode == "xml":
+	switch a.Mode {
+	case "xml":
 		content = a.InnerXML
-	case a.Mode == "escaped":
+	case "escaped":
 		content = a.CharData
-	case a.Mode == "base64":
+	case "base64":
 		b, err := base64.StdEncoding.DecodeString(a.CharData)
 		if err == nil {
 			content = string(b)

internal/reader/opml/handler.go

@@ -77,7 +77,9 @@ func (h *Handler) Import(userID int64, data io.Reader) error {
 				Category:    category,
 			}
 
-			h.store.CreateFeed(feed)
+			if err := h.store.CreateFeed(feed); err != nil {
+				return fmt.Errorf(`opml: unable to create this feed: %q`, subscription.FeedURL)
+			}
 		}
 	}
 

internal/reader/rss/adapter.go

@@ -39,7 +39,7 @@ func (r *RSSAdapter) BuildFeed(baseURL string) *model.Feed {
 	}
 
 	// Try to find the feed URL from the Atom links.
-	for _, atomLink := range r.rss.Channel.AtomLinks.Links {
+	for _, atomLink := range r.rss.Channel.Links {
 		atomLinkHref := strings.TrimSpace(atomLink.Href)
 		if atomLinkHref != "" && atomLink.Rel == "self" {
 			if absoluteFeedURL, err := urllib.AbsoluteURL(feed.FeedURL, atomLinkHref); err == nil {
@@ -189,7 +189,7 @@ func findEntryURL(rssItem *RSSItem) string {
 		}
 	}
 
-	for _, atomLink := range rssItem.AtomLinks.Links {
+	for _, atomLink := range rssItem.Links {
 		if atomLink.Href != "" && (strings.EqualFold(atomLink.Rel, "alternate") || atomLink.Rel == "") {
 			return strings.TrimSpace(atomLink.Href)
 		}
@@ -253,8 +253,8 @@ func findEntryAuthor(rssItem *RSSItem) string {
 		author = rssItem.ItunesAuthor
 	case rssItem.DublinCoreCreator != "":
 		author = rssItem.DublinCoreCreator
-	case rssItem.AtomAuthor.PersonName() != "":
-		author = rssItem.AtomAuthor.PersonName()
+	case rssItem.PersonName() != "":
+		author = rssItem.PersonName()
 	case strings.Contains(rssItem.Author.Inner, "<![CDATA["):
 		author = rssItem.Author.Data
 	default:

internal/reader/sanitizer/sanitizer.go

@@ -283,9 +283,10 @@ func isPixelTracker(tagName string, attributes []html.Attribute) bool {
 
 	for _, attribute := range attributes {
 		if attribute.Val == "1" {
-			if attribute.Key == "height" {
+			switch attribute.Key {
+			case "height":
 				hasHeight = true
-			} else if attribute.Key == "width" {
+			case "width":
 				hasWidth = true
 			}
 		}

internal/reader/sanitizer/srcset.go

@@ -49,10 +49,10 @@ func parseImageCandidate(input string) (*ImageCandidate, error) {
 	parts := strings.Split(strings.TrimSpace(input), " ")
 	nbParts := len(parts)
 
-	switch {
-	case nbParts == 1:
+	switch nbParts {
+	case 1:
 		return &ImageCandidate{ImageURL: parts[0]}, nil
-	case nbParts == 2:
+	case 2:
 		if !isValidWidthOrDensityDescriptor(parts[1]) {
 			return nil, fmt.Errorf(`srcset: invalid descriptor`)
 		}