Only reset status to "" if a text/plain part without signature is received

Otherwise sending a message without plaintext part
resets the signature. It is particularly dangerous
in multidevice case, because it's easy to accidentally
reset the signature on your other device with a non-text message.

CHANGELOG.md

@@ -31,6 +31,7 @@
 - Show a warning if quota list is empty #4261
 - Update "accounts.toml" atomically
 - Don't let blocking be bypassed using groups #4316 
+- Do not reset status on other devices when sending signed reaction messages #3692
 
 ## [1.112.7] - 2023-04-17
 

src/mimeparser.rs

@@ -90,6 +90,9 @@ pub(crate) struct MimeMessage {
     pub(crate) delivery_report: Option<DeliveryReport>,
 
     /// Standard USENET signature, if any.
+    ///
+    /// `None` means no text part was received, empty string means a text part without a footer is
+    /// received.
     pub(crate) footer: Option<String>,
 
     // if this flag is set, the parts/text/etc. are just close to the original mime-message;
@@ -1059,6 +1062,7 @@ impl MimeMessage {
                             }
                         };
 
+                        let is_plaintext = mime_type == mime::TEXT_PLAIN;
                         let mut dehtml_failed = false;
 
                         let SimplifiedText {
@@ -1139,7 +1143,9 @@ impl MimeMessage {
                             self.is_forwarded = true;
                         }
 
-                        self.footer = footer;
+                        if self.footer.is_none() && is_plaintext {
+                            self.footer = Some(footer.unwrap_or_default());
+                        }
                     }
                     _ => {}
                 }

src/receive_imf.rs

@@ -309,28 +309,25 @@ pub(crate) async fn receive_imf_inner(
         }
     }
 
-    // Always update the status, even if there is no footer, to allow removing the status.
-    //
-    // Ignore MDNs though, as they never contain the signature even if user has set it.
     // Ignore footers from mailinglists as they are often created or modified by the mailinglist software.
-    if mime_parser.mdn_reports.is_empty()
-        && !mime_parser.is_mailinglist_message()
-        && is_partial_download.is_none()
-        && from_id != ContactId::UNDEFINED
-        && context
-            .update_contacts_timestamp(from_id, Param::StatusTimestamp, sent_timestamp)
-            .await?
-    {
-        if let Err(err) = contact::set_status(
-            context,
-            from_id,
-            mime_parser.footer.clone().unwrap_or_default(),
-            mime_parser.was_encrypted(),
-            mime_parser.has_chat_version(),
-        )
-        .await
+    if let Some(footer) = &mime_parser.footer {
+        if !mime_parser.is_mailinglist_message()
+            && from_id != ContactId::UNDEFINED
+            && context
+                .update_contacts_timestamp(from_id, Param::StatusTimestamp, sent_timestamp)
+                .await?
         {
-            warn!(context, "Cannot update contact status: {err:#}.");
+            if let Err(err) = contact::set_status(
+                context,
+                from_id,
+                footer.to_string(),
+                mime_parser.was_encrypted(),
+                mime_parser.has_chat_version(),
+            )
+            .await
+            {
+                warn!(context, "Cannot update contact status: {err:#}.");
+            }
         }
     }