libsql: Fix SyncContext::new() metadata reading

If we fail to read the metadata file, we must return an error. Resetting
the metadata leads to inconsistent state because you have no way to tell
what the database represents.

Author: penberg

libsql/src/sync.rs

@@ -169,14 +169,10 @@ impl SyncContext {
             initial_server_sync: false,
             remote_encryption,
         };
-
-        if let Err(e) = me.read_metadata().await {
-            tracing::error!(
-                "failed to read sync metadata file, resetting back to defaults: {}",
-                e
-            );
+        me.read_metadata().await?;
+        if me.durable_generation == 0 {
+            return Err(SyncError::InvalidLocalState("generation is 0".to_string()).into());
         }
-
         Ok(me)
     }
 

libsql/src/sync/test.rs

@@ -14,6 +14,7 @@ async fn test_sync_context_push_frame() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     let sync_ctx = SyncContext::new(
         server.connector(),
@@ -44,6 +45,7 @@ async fn test_sync_context_with_auth() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     let sync_ctx = SyncContext::new(
         server.connector(),
@@ -69,6 +71,7 @@ async fn test_sync_context_multiple_frames() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     let sync_ctx = SyncContext::new(
         server.connector(),
@@ -98,6 +101,7 @@ async fn test_sync_context_corrupted_metadata() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     // Create initial sync context and push a frame
     let sync_ctx = SyncContext::new(
@@ -129,12 +133,9 @@ async fn test_sync_context_corrupted_metadata() {
         None,
         None,
     )
-    .await
-    .unwrap();
+    .await;
 
-    // Verify that the context was reset to default values
-    assert_eq!(sync_ctx.durable_frame_num(), 0);
-    assert_eq!(sync_ctx.durable_generation(), 0);
+    assert!(sync_ctx.is_err());
 }
 
 #[tokio::test]
@@ -144,6 +145,7 @@ async fn test_sync_restarts_with_lower_max_frame_no() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     // Create initial sync context and push a frame
     let sync_ctx = SyncContext::new(
@@ -211,6 +213,7 @@ async fn test_sync_context_retry_on_error() {
     let server = MockServer::start();
     let temp_dir = tempdir().unwrap();
     let db_path = temp_dir.path().join("test.db");
+    gen_metadata_file(&db_path, 3278479626, 0, 0, 1);
 
     let sync_ctx = SyncContext::new(
         server.connector(),
@@ -475,3 +478,15 @@ impl hyper::client::connect::Connection for MockConnection {
         hyper::client::connect::Connected::new()
     }
 }
+
+fn gen_metadata_file(db_path: &Path, hash: u32, version: u32, durable_frame_num: u32, generation: u32) {
+    let metadata_path = format!("{}-info", db_path.to_str().unwrap());
+    std::fs::write(
+        &metadata_path,
+        format!(
+            "{{\"hash\": {hash}, \"version\": {version}, \"durable_frame_num\": {durable_frame_num}, \"generation\": {generation}}}"
+        )
+        .as_bytes(),
+    )
+    .unwrap();
+}