Prevent panics when remote datastore transactions fail to start

lib/src/dbs/executor.rs

@@ -79,8 +79,7 @@ impl<'a> Executor<'a> {
 
 	async fn cancel(&mut self, local: bool) {
 		if local {
-			match self.txn.as_ref() {
+			if let Some(txn) = self.txn.as_ref() {
-				Some(txn) => {
 				let txn = txn.clone();
 				let mut txn = txn.lock().await;
 				if txn.cancel().await.is_err() {
@@ -88,8 +87,6 @@ impl<'a> Executor<'a> {
 				}
 				self.txn = None;
 			}
-				None => unreachable!(),
-			}
 		}
 	}
 
@@ -212,6 +209,12 @@ impl<'a> Executor<'a> {
 				Statement::Set(stm) => {
 					// Create a transaction
 					let loc = self.begin(stm.writeable()).await;
+					// Check the transaction
+					match self.err {
+						// We failed to create a transaction
+						true => Err(Error::TxFailure),
+						// The transaction began successfully
+						false => {
 							// Process the statement
 							match stm.compute(&ctx, &opt, &self.txn(), None).await {
 								Ok(val) => {
@@ -227,6 +230,8 @@ impl<'a> Executor<'a> {
 							// Return nothing
 							Ok(Value::None)
 						}
+					}
+				}
 				// Process all other normal statements
 				_ => match self.err {
 					// This transaction has failed
@@ -235,6 +240,12 @@ impl<'a> Executor<'a> {
 					false => {
 						// Create a transaction
 						let loc = self.begin(stm.writeable()).await;
+						// Check the transaction
+						match self.err {
+							// We failed to create a transaction
+							true => Err(Error::TxFailure),
+							// The transaction began successfully
+							false => {
 								// Process the statement
 								let res = match stm.timeout() {
 									// There is a timeout clause
@@ -264,6 +275,8 @@ impl<'a> Executor<'a> {
 								// Return the result
 								res
 							}
+						}
+					}
 				},
 			};
 			// Get the statement end time

lib/src/err/mod.rs

@@ -21,6 +21,10 @@ pub enum Error {
 	#[error("There was a problem with a datastore transaction: {0}")]
 	Tx(String),
 
+	/// There was an error when starting a new datastore transaction
+	#[error("There was an error when starting a new datastore transaction")]
+	TxFailure,
+
 	/// The transaction was already cancelled or committed
 	#[error("Couldn't update a finished transaction")]
 	TxFinished,