Editor: Fix handling empty input

hyphae/deprecated.go

@@ -1,7 +1,6 @@
 package hyphae
 
 import (
-	"errors"
 	"os"
 )
 
@@ -11,7 +10,7 @@ import (
 func FetchMycomarkupFile(h Hypha) (string, error) {
 	switch h := h.(type) {
 	case *EmptyHypha:
-		return "", errors.New("empty hyphae have no text")
+		return "", nil
 	case *MediaHypha:
 		if !h.HasTextFile() {
 			return "", nil

shroom/upload.go

@@ -62,17 +62,16 @@ func UploadText(h hyphae.Hypha, data []byte, userMessage string, u *user.User) e
 		return errors.New("invalid hypha name")
 	}
 
+	oldText, err := hyphae.FetchMycomarkupFile(h)
+	if err != nil {
+		hop.Abort()
+		return err
+	}
+
 	// Empty data check
-	if len(bytes.TrimSpace(data)) == 0 { // if nothing but whitespace
-		switch h.(type) {
-		case *hyphae.EmptyHypha, *hyphae.MediaHypha:
-			// Writing no description, it's ok, just like cancel button.
+	if len(bytes.TrimSpace(data)) == 0 && len(oldText) == 0 { // if nothing but whitespace
 		hop.Abort()
 		return nil
-		case *hyphae.TextualHypha:
-			// What do you want passing nothing for a textual hypha?
-			return errors.New("No data passed")
-		}
 	}
 
 	// At this point, we have a savable user-generated Mycomarkup document. Gotta save it.
@@ -90,12 +89,6 @@ func UploadText(h hyphae.Hypha, data []byte, userMessage string, u *user.User) e
 		hyphae.Insert(H)
 		backlinks.UpdateBacklinksAfterEdit(H, "")
 	case *hyphae.MediaHypha:
-		oldText, err := hyphae.FetchMycomarkupFile(h)
-		if err != nil {
-			hop.Abort()
-			return err
-		}
-
 		// TODO: that []byte(...) part should be removed
 		if bytes.Equal(data, []byte(oldText)) {
 			// No changes! Just like cancel button