forward,recall: fix charsets in part attachment

Fix charset to UTF-8 in part attachments. The forward and recall
commands fetch message parts with the go-message package which decodes
to UTF-8. Hence, we should set the charset of the part attachment to
utf-8 and not just copying over the one from the original message.

Reported-by: Bence Ferdinandy <bence@ferdinandy.com>
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

commands/msg/forward.go

@@ -198,12 +198,13 @@ func (forward) Execute(aerc *widgets.Aerc, args []string) error {
 					}
 					store.FetchBodyPart(msg.Uid, p, func(reader io.Reader) {
 						mime := fmt.Sprintf("%s/%s", bs.MIMEType, bs.MIMESubType)
-						name, ok := bs.Params["name"]
+						params := lib.SetUtf8Charset(bs.Params)
+						name, ok := params["name"]
 						if !ok {
 							name = fmt.Sprintf("%s_%s_%d", bs.MIMEType, bs.MIMESubType, rand.Uint64())
 						}
 						mu.Lock()
-						composer.AddPartAttachment(name, mime, bs.Params, reader)
+						composer.AddPartAttachment(name, mime, params, reader)
 						mu.Unlock()
 					})
 				}

commands/msg/recall.go

@@ -204,12 +204,13 @@ func (Recall) Execute(aerc *widgets.Aerc, args []string) error {
 					}
 					msg.FetchBodyPart(p, func(reader io.Reader) {
 						mime := fmt.Sprintf("%s/%s", bs.MIMEType, bs.MIMESubType)
-						name, ok := bs.Params["name"]
+						params := lib.SetUtf8Charset(bs.Params)
+						name, ok := params["name"]
 						if !ok {
 							name = fmt.Sprintf("%s_%s_%d", bs.MIMEType, bs.MIMESubType, rand.Uint64())
 						}
 						mu.Lock()
-						composer.AddPartAttachment(name, mime, bs.Params, reader)
+						composer.AddPartAttachment(name, mime, params, reader)
 						mu.Unlock()
 					})
 				}