Correctly clear database cache after import (#4067)

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Start SQL transactions with IMMEDIATE behaviour rather than default DEFERRED one. #4063
 - Fix a problem with Gmail where (auto-)deleted messages would get archived instead of deleted.
   Move them to the Trash folder for Gmail which auto-deletes trashed messages in 30 days #3972
+- Clear config cache after backup import. This bug sometimes resulted in the import to seemingly work at first. #4067
 
 ### API-Changes
 

src/imex.rs

@@ -427,8 +427,6 @@ async fn import_backup(
         context.get_dbfile().display()
     );
 
-    context.sql.config_cache.write().await.clear();
-
     let mut archive = Archive::new(backup_file);
 
     let mut entries = archive.entries()?;
@@ -785,7 +783,10 @@ where
 
 #[cfg(test)]
 mod tests {
+    use std::time::Duration;
+
     use ::pgp::armor::BlockType;
+    use tokio::task;
 
     use super::*;
     use crate::pgp::{split_armored_data, HEADER_AUTOCRYPT, HEADER_SETUPCODE};
@@ -933,6 +934,46 @@ mod tests {
         Ok(())
     }
 
+    /// This is a regression test for
+    /// https://github.com/deltachat/deltachat-android/issues/2263
+    /// where the config cache wasn't reset properly after a backup.
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_import_backup_reset_config_cache() -> Result<()> {
+        let backup_dir = tempfile::tempdir()?;
+        let context1 = TestContext::new_alice().await;
+        let context2 = TestContext::new().await;
+        assert!(!context2.is_configured().await?);
+
+        // export from context1
+        imex(&context1, ImexMode::ExportBackup, backup_dir.path(), None).await?;
+
+        // import to context2
+        let backup = has_backup(&context2, backup_dir.path()).await?;
+        let context2_cloned = context2.clone();
+        let handle = task::spawn(async move {
+            imex(
+                &context2_cloned,
+                ImexMode::ImportBackup,
+                backup.as_ref(),
+                None,
+            )
+            .await
+            .unwrap();
+        });
+
+        while !handle.is_finished() {
+            // The database is still unconfigured;
+            // fill the config cache with the old value.
+            context2.is_configured().await.ok();
+            tokio::time::sleep(Duration::from_micros(1)).await;
+        }
+
+        // Assert that the config cache has the new value now.
+        assert!(context2.is_configured().await?);
+
+        Ok(())
+    }
+
     #[test]
     fn test_normalize_setup_code() {
         let norm = normalize_setup_code("123422343234423452346234723482349234");

src/sql.rs

@@ -129,43 +129,49 @@ impl Sql {
             .to_str()
             .with_context(|| format!("path {path:?} is not valid unicode"))?
             .to_string();
-        self.call(move |conn| {
+        let res = self
-            // Check that backup passphrase is correct before resetting our database.
+            .call(move |conn| {
-            conn.execute(
+                // Check that backup passphrase is correct before resetting our database.
-                "ATTACH DATABASE ? AS backup KEY ?",
+                conn.execute(
-                paramsv![path_str, passphrase],
+                    "ATTACH DATABASE ? AS backup KEY ?",
-            )
+                    paramsv![path_str, passphrase],
-            .context("failed to attach backup database")?;
+                )
-            if let Err(err) = conn
+                .context("failed to attach backup database")?;
-                .query_row("SELECT count(*) FROM sqlite_master", [], |_row| Ok(()))
+                if let Err(err) = conn
-                .context("backup passphrase is not correct")
+                    .query_row("SELECT count(*) FROM sqlite_master", [], |_row| Ok(()))
-            {
+                    .context("backup passphrase is not correct")
+                {
+                    conn.execute("DETACH DATABASE backup", [])
+                        .context("failed to detach backup database")?;
+                    return Err(err);
+                }
+
+                // Reset the database without reopening it. We don't want to reopen the database because we
+                // don't have main database passphrase at this point.
+                // See <https://sqlite.org/c3ref/c_dbconfig_enable_fkey.html> for documentation.
+                // Without resetting import may fail due to existing tables.
+                conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, true)
+                    .context("failed to set SQLITE_DBCONFIG_RESET_DATABASE")?;
+                conn.execute("VACUUM", [])
+                    .context("failed to vacuum the database")?;
+                conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, false)
+                    .context("failed to unset SQLITE_DBCONFIG_RESET_DATABASE")?;
+                let res = conn
+                    .query_row("SELECT sqlcipher_export('main', 'backup')", [], |_row| {
+                        Ok(())
+                    })
+                    .context("failed to import from attached backup database");
                 conn.execute("DETACH DATABASE backup", [])
                     .context("failed to detach backup database")?;
-                return Err(err);
+                res?;
-            }
+                Ok(())
+            })
+            .await;
 
-            // Reset the database without reopening it. We don't want to reopen the database because we
+        // The config cache is wrong now that we have a different database
-            // don't have main database passphrase at this point.
+        self.config_cache.write().await.clear();
-            // See <https://sqlite.org/c3ref/c_dbconfig_enable_fkey.html> for documentation.
+
-            // Without resetting import may fail due to existing tables.
+        res
-            conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, true)
-                .context("failed to set SQLITE_DBCONFIG_RESET_DATABASE")?;
-            conn.execute("VACUUM", [])
-                .context("failed to vacuum the database")?;
-            conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, false)
-                .context("failed to unset SQLITE_DBCONFIG_RESET_DATABASE")?;
-            let res = conn
-                .query_row("SELECT sqlcipher_export('main', 'backup')", [], |_row| {
-                    Ok(())
-                })
-                .context("failed to import from attached backup database");
-            conn.execute("DETACH DATABASE backup", [])
-                .context("failed to detach backup database")?;
-            res?;
-            Ok(())
-        })
-        .await
     }
 
     /// Creates a new connection pool.