fix: Save QR code token regardless of whether the group exists (#5954)

Groups promotion to other devices and QR code tokens synchronisation are not synchronised processes,
so there are reasons why a QR code token may arrive earlier than the first group message:
- We are going to upload sync messages via IMAP while group messages are sent by SMTP.
- If sync messages go to the mvbox, they can be fetched earlier than group messages from Inbox.

src/token.rs

@@ -7,7 +7,6 @@
 use anyhow::Result;
 use deltachat_derive::{FromSql, ToSql};
 
-use crate::chat::ChatId;
 use crate::context::Context;
 use crate::tools::{create_id, time};
 
@@ -27,34 +26,22 @@ pub enum Namespace {
 pub async fn save(
     context: &Context,
     namespace: Namespace,
-    foreign_id: Option<ChatId>,
+    foreign_key: Option<&str>,
     token: &str,
 ) -> Result<()> {
-    match foreign_id {
-        Some(foreign_id) => context
-            .sql
-            .execute(
-                "INSERT INTO tokens (namespc, foreign_id, token, timestamp) VALUES (?, ?, ?, ?);",
-                (namespace, foreign_id, token, time()),
-            )
-            .await?,
-        None => {
-            context
-                .sql
-                .execute(
-                    "INSERT INTO tokens (namespc, token, timestamp) VALUES (?, ?, ?);",
-                    (namespace, token, time()),
-                )
-                .await?
-        }
-    };
-
+    context
+        .sql
+        .execute(
+            "INSERT INTO tokens (namespc, foreign_key, token, timestamp) VALUES (?, ?, ?, ?)",
+            (namespace, foreign_key.unwrap_or(""), token, time()),
+        )
+        .await?;
     Ok(())
 }
 
-/// Lookup most recently created token for a namespace/chat combination.
+/// Looks up most recently created token for a namespace / foreign key combination.
 ///
-/// As there may be more than one valid token for a chat-id,
+/// As there may be more than one such valid token,
 /// (eg. when a qr code token is withdrawn, recreated and revived later),
 /// use lookup() for qr-code creation only;
 /// do not use lookup() to check for token validity.
@@ -63,43 +50,28 @@ pub async fn save(
 pub async fn lookup(
     context: &Context,
     namespace: Namespace,
-    chat: Option<ChatId>,
+    foreign_key: Option<&str>,
 ) -> Result<Option<String>> {
-    let token = match chat {
-        Some(chat_id) => {
-            context
-                .sql
-                .query_get_value(
-                    "SELECT token FROM tokens WHERE namespc=? AND foreign_id=? ORDER BY timestamp DESC LIMIT 1;",
-                    (namespace, chat_id),
-                )
-                .await?
-        }
-        // foreign_id is declared as `INTEGER DEFAULT 0` in the schema.
-        None => {
-            context
-                .sql
-                .query_get_value(
-                    "SELECT token FROM tokens WHERE namespc=? AND foreign_id=0 ORDER BY timestamp DESC LIMIT 1;",
-                    (namespace,),
-                )
-                .await?
-        }
-    };
-    Ok(token)
+    context
+        .sql
+        .query_get_value(
+            "SELECT token FROM tokens WHERE namespc=? AND foreign_key=? ORDER BY timestamp DESC LIMIT 1",
+            (namespace, foreign_key.unwrap_or("")),
+        )
+        .await
 }
 
 pub async fn lookup_or_new(
     context: &Context,
     namespace: Namespace,
-    foreign_id: Option<ChatId>,
+    foreign_key: Option<&str>,
 ) -> Result<String> {
-    if let Some(token) = lookup(context, namespace, foreign_id).await? {
+    if let Some(token) = lookup(context, namespace, foreign_key).await? {
         return Ok(token);
     }
 
     let token = create_id();
-    save(context, namespace, foreign_id, &token).await?;
+    save(context, namespace, foreign_key, &token).await?;
     Ok(token)
 }
 
@@ -114,23 +86,22 @@ pub async fn exists(context: &Context, namespace: Namespace, token: &str) -> Res
     Ok(exists)
 }
 
-/// Looks up ChatId by auth token.
+/// Looks up foreign key by auth token.
 ///
 /// Returns None if auth token is not valid.
-/// Returns zero/unset ChatId if the token corresponds to "setup contact" rather than group join.
-pub async fn auth_chat_id(context: &Context, token: &str) -> Result<Option<ChatId>> {
-    let chat_id: Option<ChatId> = context
+/// Returns an empty string if the token corresponds to "setup contact" rather than group join.
+pub async fn auth_foreign_key(context: &Context, token: &str) -> Result<Option<String>> {
+    context
         .sql
         .query_row_optional(
-            "SELECT foreign_id FROM tokens WHERE namespc=? AND token=?",
+            "SELECT foreign_key FROM tokens WHERE namespc=? AND token=?",
             (Namespace::Auth, token),
             |row| {
-                let chat_id: ChatId = row.get(0)?;
-                Ok(chat_id)
+                let foreign_key: String = row.get(0)?;
+                Ok(foreign_key)
             },
         )
-        .await?;
-    Ok(chat_id)
+        .await
 }
 
 pub async fn delete(context: &Context, namespace: Namespace, token: &str) -> Result<()> {