Unify error messages

feed.go

@@ -2,7 +2,6 @@ package atom
 
 import (
 	"encoding/xml"
-	"errors"
 	"fmt"
 	"time"
 )
@@ -121,10 +120,10 @@ func (f *Feed) AddEntry(e *Entry) {
 // error.
 func (f *Feed) Check() error {
 	if f.ID == nil {
-		return errors.New("no id element of feed")
+		return fmt.Errorf("no id element of feed %v", f)
 	} else {
 		if err := f.ID.Check(); err != nil {
-			return fmt.Errorf("id element of feed: %v", err)
+			return fmt.Errorf("id element of feed %v: %v", f, err)
 		}
 	}
 
@@ -134,93 +133,93 @@ func (f *Feed) Check() error {
 	if f.Authors == nil {
 		for _, e := range f.Entries {
 			if err := e.checkAuthors(false); err != nil {
-				return fmt.Errorf("no authors set in feed %v: %v", f.ID.URI, err)
+				return fmt.Errorf("no authors set in feed %v: %v", f, err)
 			}
 		}
 	} else {
 		for i, a := range f.Authors {
 			if err := a.Check(); err != nil {
-				return fmt.Errorf("author element %v of feed %v: %v", i, f.ID.URI, err)
+				return fmt.Errorf("author element %v of feed %v: %v", i, f, err)
 			}
 		}
 	}
 
 	for i, c := range f.Categories {
 		if err := c.Check(); err != nil {
-			return fmt.Errorf("category element %v of feed %v: %v", i, f.ID.URI, err)
+			return fmt.Errorf("category element %v of feed %v: %v", i, f, err)
 		}
 	}
 
 	for i, c := range f.Contributors {
 		if err := c.Check(); err != nil {
-			return fmt.Errorf("contributor element %v of feed %v: %v", i, f.ID.URI, err)
+			return fmt.Errorf("contributor element %v of feed %v: %v", i, f, err)
 		}
 	}
 
 	if f.Generator != nil {
 		if err := f.Generator.Check(); err != nil {
-			return fmt.Errorf("generator element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("generator element of feed %v: %v", f, err)
 		}
 	}
 
 	if f.Icon != nil {
 		if err := f.Icon.Check(); err != nil {
-			return fmt.Errorf("icon element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("icon element of feed %v: %v", f, err)
 		}
 	}
 
 	for i, l := range f.Links {
 		if err := l.Check(); err != nil {
-			return fmt.Errorf("link element %v of feed %v: %v", i, f.ID.URI, err)
+			return fmt.Errorf("link element %v of feed %v: %v", i, f, err)
 		}
 	}
 	if hasAlternateDuplicateLinks(f.Links) {
-		return fmt.Errorf("links with with a rel attribute value of \"alternate\" and duplicate type and hreflang attribute values found in feed %v", f.ID.URI)
+		return fmt.Errorf("links with a rel attribute value of \"alternate\" and duplicate type and hreflang attribute values found in feed %v", f)
 	}
 
 	if f.Logo != nil {
 		if err := f.Logo.Check(); err != nil {
-			return fmt.Errorf("logo element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("logo element of feed %v: %v", f, err)
 		}
 	}
 
 	if f.Rights != nil {
 		if err := f.Rights.Check(); err != nil {
-			return fmt.Errorf("rights element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("rights element of feed %v: %v", f, err)
 		}
 	}
 
 	if f.Subtitle != nil {
 		if err := f.Subtitle.Check(); err != nil {
-			return fmt.Errorf("subtitle element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("subtitle element of feed %v: %v", f, err)
 		}
 	}
 
 	if f.Title == nil {
-		return fmt.Errorf("no title element of feed %v", f.ID.URI)
+		return fmt.Errorf("no title element of feed %v", f)
 	} else {
 		if err := f.Title.Check(); err != nil {
-			return fmt.Errorf("title element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("title element of feed %v: %v", f, err)
 		}
 	}
 
 	if f.Updated == nil {
-		return fmt.Errorf("no updated element of feed %v", f.ID)
+		return fmt.Errorf("no updated element of feed %v", f)
 	} else {
 		if err := f.Updated.Check(); err != nil {
-			return fmt.Errorf("updated element of feed %v: %v", f.ID.URI, err)
+			return fmt.Errorf("updated element of feed %v: %v", f, err)
 		}
 	}
 
 	for i, x := range f.Extensions {
 		if err := x.Check(); err != nil {
-			return fmt.Errorf("extension element %v of feed %v: %v", i, f.ID.URI, err)
+			return fmt.Errorf("extension element %v of feed %v: %v", i, f, err)
 		}
 	}
 
 	for i, n := range f.Entries {
 		if err := n.Check(); err != nil {
-			return fmt.Errorf("entry element %v of feed %v: %v", i, f.ID.URI, err)
+			return fmt.Errorf("entry element %v of feed %v: %v", i, f, err)
 		}
 	}