fix: Emit MsgsChanged, not IncomingMsg, for messages only having special parts (#8157)

An example of such messages is location-only messages.

Co-authored-by: Hocuri <hocuri@gmx.de>

src/decrypt.rs

@@ -1,6 +1,7 @@
 //! Helper functions for decryption.
 //! The actual decryption is done in the [`crate::pgp`] module.
 
+use std::collections::HashSet;
 use std::io::Cursor;
 
 use anyhow::{Context as _, Result, bail};
@@ -18,8 +19,8 @@ use crate::chat::ChatId;
 use crate::constants::Chattype;
 use crate::contact::ContactId;
 use crate::context::Context;
-use crate::key::load_self_secret_keyring;
 use crate::key::self_fingerprint;
+use crate::key::{Fingerprint, SignedPublicKey, load_self_secret_keyring};
 use crate::token::Namespace;
 
 /// Tries to decrypt the message,
@@ -334,6 +335,36 @@ fn get_autocrypt_mime<'a, 'b>(mail: &'a ParsedMail<'b>) -> Option<&'a ParsedMail
     }
 }
 
+/// Validates signatures of Multipart/Signed message part, as defined in RFC 1847.
+///
+/// Returns the signed part and the set of key
+/// fingerprints for which there is a valid signature.
+///
+/// Returns None if the message is not Multipart/Signed or doesn't contain necessary parts.
+pub(crate) fn validate_detached_signature<'a, 'b>(
+    mail: &'a ParsedMail<'b>,
+    public_keyring_for_validate: &[SignedPublicKey],
+) -> Option<(&'a ParsedMail<'b>, HashSet<Fingerprint>)> {
+    if mail.ctype.mimetype != "multipart/signed" {
+        return None;
+    }
+
+    if let [first_part, second_part] = &mail.subparts[..] {
+        // First part is the content, second part is the signature.
+        let content = first_part.raw_bytes;
+        let ret_valid_signatures = match second_part.get_body_raw() {
+            Ok(signature) => {
+                crate::pgp::pk_validate(content, &signature, public_keyring_for_validate)
+                    .unwrap_or_default()
+            }
+            Err(_) => Default::default(),
+        };
+        Some((first_part, ret_valid_signatures))
+    } else {
+        None
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/location.rs

@@ -871,7 +871,7 @@ mod tests {
     use crate::config::Config;
     use crate::message::MessageState;
     use crate::receive_imf::receive_imf;
-    use crate::test_utils::{TestContext, TestContextManager};
+    use crate::test_utils::{ExpectedEvents, TestContext, TestContextManager};
     use crate::tools::SystemTime;
 
     #[test]
@@ -1103,6 +1103,9 @@ Content-Disposition: attachment; filename="location.kml"
             .await?;
 
         let alice_chat = alice.create_chat(bob).await;
+        // Bob needs the chat accepted so that "normal" messages from Alice trigger `IncomingMsg`.
+        // Location-only messages still must trigger `MsgsChanged`.
+        bob.create_chat(alice).await;
 
         // Alice enables location streaming.
         // Bob receives a message saying that Alice enabled location streaming.
@@ -1117,7 +1120,18 @@ Content-Disposition: attachment; filename="location.kml"
         SystemTime::shift(Duration::from_secs(10));
         delete_expired(alice, time()).await?;
         maybe_send(alice).await?;
+        bob.evtracker.clear_events();
         bob.recv_msg_opt(&alice.pop_sent_msg().await).await;
+        bob.evtracker
+            .get_matching_ex(
+                bob,
+                ExpectedEvents {
+                    expected: |e| matches!(e, EventType::MsgsChanged { .. }),
+                    unexpected: |e| matches!(e, EventType::IncomingMsg { .. }),
+                },
+            )
+            .await
+            .unwrap();
         assert_eq!(get_range(alice, None, None, 0, 0).await?.len(), 1);
         assert_eq!(get_range(bob, None, None, 0, 0).await?.len(), 1);
 

src/mimeparser.rs

@@ -20,7 +20,7 @@ use crate::config::Config;
 use crate::constants;
 use crate::contact::{ContactId, import_public_key};
 use crate::context::Context;
-use crate::decrypt::{self};
+use crate::decrypt::{self, validate_detached_signature};
 use crate::dehtml::dehtml;
 use crate::download::PostMsgMetadata;
 use crate::events::EventType;
@@ -487,6 +487,17 @@ impl MimeMessage {
             HashMap::new()
         };
 
+        let mail = mail.as_ref().map(|mail| {
+            let (content, signatures_detached) = validate_detached_signature(mail, &public_keyring)
+                .unwrap_or((mail, Default::default()));
+            let signatures_detached = signatures_detached
+                .into_iter()
+                .map(|fp| (fp, Vec::new()))
+                .collect::<HashMap<_, _>>();
+            signatures.extend(signatures_detached);
+            content
+        });
+
         if let Some(expected_sender_fingerprint) = expected_sender_fingerprint {
             ensure!(
                 !signatures.is_empty(),
@@ -502,7 +513,7 @@ impl MimeMessage {
             );
         }
 
-        if let (Ok(mail), true) = (&mail, is_encrypted) {
+        if let (Ok(mail), true) = (mail, is_encrypted) {
             if !signatures.is_empty() {
                 // Unsigned "Subject" mustn't be prepended to messages shown as encrypted
                 // (<https://github.com/deltachat/deltachat-core-rust/issues/1790>).
@@ -527,7 +538,7 @@ impl MimeMessage {
                 &mut inner_from,
                 &mut list_post,
                 &mut chat_disposition_notification_to,
-                &mail,
+                mail,
             );
 
             if !signatures.is_empty() {
@@ -571,7 +582,7 @@ impl MimeMessage {
             signatures.clear();
         }
 
-        if let (Ok(mail), true) = (&mail, is_encrypted)
+        if let (Ok(mail), true) = (mail, is_encrypted)
             && let Some(post_msg_rfc724_mid) =
                 mail.headers.get_header_value(HeaderDef::ChatPostMessageId)
         {
@@ -629,7 +640,7 @@ impl MimeMessage {
             from,
             incoming,
             chat_disposition_notification_to,
-            decryption_error: mail.as_ref().err().map(|err| format!("{err:#}")),
+            decryption_error: mail.err().map(|err| format!("{err:#}")),
 
             // only non-empty if it was a valid autocrypt message
             signature,
@@ -655,9 +666,9 @@ impl MimeMessage {
             pre_message,
         };
 
-        match &mail {
+        match mail {
             Ok(mail) => {
-                parser.parse_mime_recursive(context, &mail, false).await?;
+                parser.parse_mime_recursive(context, mail, false).await?;
             }
             Err(err) => {
                 let txt = "[This message cannot be decrypted.\n\n• It might already help to simply reply to this message and ask the sender to send the message again.\n\n• If you just re-installed Delta Chat then it is best if you re-setup Delta Chat now and choose \"Add as second device\" or import a backup.]";

src/receive_imf.rs

@@ -1019,8 +1019,15 @@ UPDATE msgs SET state=? WHERE
         let is_bot = context.get_config_bool(Config::Bot).await?;
         let is_pre_message = matches!(mime_parser.pre_message, PreMessageMode::Pre { .. });
         let skip_bot_notify = is_bot && is_pre_message;
-        let important =
-            mime_parser.incoming && fresh && !is_old_contact_request && !skip_bot_notify;
+        let is_empty = !is_pre_message
+            && mime_parser.parts.first().is_none_or(|p| {
+                p.typ == Viewtype::Text && p.msg.is_empty() && p.param.get(Param::Quote).is_none()
+            });
+        let important = mime_parser.incoming
+            && !is_empty
+            && fresh
+            && !is_old_contact_request
+            && !skip_bot_notify;
 
         for msg_id in &received_msg.msg_ids {
             chat_id.emit_msg_event(context, *msg_id, important);

src/test_utils.rs

@@ -1431,6 +1431,12 @@ pub fn fiona_keypair() -> SignedSecretKey {
 #[derive(Debug)]
 pub struct EventTracker(EventEmitter);
 
+/// See [`super::EventTracker::get_matching_ex`].
+pub struct ExpectedEvents<E: Fn(&EventType) -> bool, U: Fn(&EventType) -> bool> {
+    pub expected: E,
+    pub unexpected: U,
+}
+
 impl Deref for EventTracker {
     type Target = EventEmitter;
 
@@ -1467,21 +1473,39 @@ impl EventTracker {
         .expect("timeout waiting for event match")
     }
 
-    /// Consumes emitted events returning the first matching one if any.
+    /// Consumes all emitted events returning the first matching one if any.
     pub async fn get_matching_opt<F: Fn(&EventType) -> bool>(
         &self,
         ctx: &Context,
         event_matcher: F,
+    ) -> Option<EventType> {
+        self.get_matching_ex(
+            ctx,
+            ExpectedEvents {
+                expected: event_matcher,
+                unexpected: |_| false,
+            },
+        )
+        .await
+    }
+
+    /// Consumes all emitted events returning the first matching one if any. Panics on unexpected
+    /// events.
+    pub async fn get_matching_ex<E: Fn(&EventType) -> bool, U: Fn(&EventType) -> bool>(
+        &self,
+        ctx: &Context,
+        args: ExpectedEvents<E, U>,
     ) -> Option<EventType> {
         ctx.emit_event(EventType::Test);
         let mut found_event = None;
         loop {
             let event = self.recv().await.unwrap();
+            assert!(!(args.unexpected)(&event.typ));
             if let EventType::Test = event.typ {
                 return found_event;
             }
-            if event_matcher(&event.typ) {
-                found_event = Some(event.typ);
+            if (args.expected)(&event.typ) {
+                found_event.get_or_insert(event.typ);
             }
         }
     }