Fix insertion race condition

sync-server/src/app_state/database.rs

@@ -370,11 +370,12 @@ impl Database {
         .context("Cannot fetch document version")
     }
 
+    // inserting the document must be the last step of the transaction if there's one
     pub async fn insert_document_version(
         &self,
         vault_id: &VaultId,
         version: &StoredDocumentVersion,
-        transaction: Option<&mut Transaction<'_>>,
+        transaction: Option<Transaction<'_>>,
     ) -> Result<()> {
         let document_id = version.document_id.as_hyphenated();
         let query = sqlx::query!(
@@ -401,14 +402,22 @@ impl Database {
             version.device_id
         );
 
-        if let Some(transaction) = transaction {
+        if let Some(mut transaction) = transaction {
-            query.execute(&mut **transaction).await
+            query
+                .execute(&mut *transaction)
+                .await
+                .context("Cannot insert document version")?;
+
+            transaction
+                .commit()
+                .await
+                .context("Failed to commit transaction")?;
         } else {
             query
                 .execute(&self.get_connection_pool(vault_id).await?)
                 .await
+                .context("Cannot insert document version")?;
         }
-        .context("Cannot insert document version")?;
 
         self.broadcasts
             .send_document_update(

sync-server/src/server/create_document.rs

@@ -1,4 +1,3 @@
-use anyhow::Context as _;
 use axum::{
     Extension, Json,
     extract::{Path, State},
@@ -82,15 +81,9 @@ pub async fn create_document(
 
     state
         .database
-        .insert_document_version(&vault_id, &new_version, Some(&mut transaction))
+        .insert_document_version(&vault_id, &new_version, Some(transaction))
         .await
         .map_err(server_error)?;
 
-    transaction
-        .commit()
-        .await
-        .context("Failed to commit successful transaction")
-        .map_err(server_error)?;
-
     Ok(Json(new_version.into()))
 }

sync-server/src/server/delete_document.rs

@@ -1,4 +1,3 @@
-use anyhow::Context as _;
 use axum::{
     Extension, Json,
     extract::{Path, State},
@@ -71,15 +70,9 @@ pub async fn delete_document(
 
     state
         .database
-        .insert_document_version(&vault_id, &new_version, Some(&mut transaction))
+        .insert_document_version(&vault_id, &new_version, Some(transaction))
         .await
         .map_err(server_error)?;
 
-    transaction
-        .commit()
-        .await
-        .context("Failed to commit successful transaction")
-        .map_err(server_error)?;
-
     Ok(Json(new_version.into()))
 }

sync-server/src/server/update_document.rs

@@ -183,16 +183,10 @@ pub async fn update_document(
 
     state
         .database
-        .insert_document_version(&vault_id, &new_version, Some(&mut transaction))
+        .insert_document_version(&vault_id, &new_version, Some(transaction))
         .await
         .map_err(server_error)?;
 
-    transaction
-        .commit()
-        .await
-        .context("Failed to commit successful transaction")
-        .map_err(server_error)?;
-
     Ok(Json(if is_different_from_request_content {
         DocumentUpdateResponse::MergingUpdate(new_version.into())
     } else {