Merge 'vdbe: Disallow checkpointing in transaction' from Jussi Saurio

Closes #2358

Reviewed-by: Preston Thorpe (@PThorpe92)

Closes #2365

core/error.rs

@@ -55,6 +55,8 @@ pub enum LimboError {
     IntegerOverflow,
     #[error("Schema is locked for write")]
     SchemaLocked,
+    #[error("Runtime error: database table is locked")]
+    TableLocked,
     #[error("Error: Resource is read-only")]
     ReadOnly,
     #[error("Database is busy")]

core/vdbe/execute.rs

@@ -334,6 +334,13 @@ pub fn op_checkpoint(
     else {
         unreachable!("unexpected Insn {:?}", insn)
     };
+    if !program.connection.auto_commit.get() {
+        // TODO: sqlite returns "Runtime error: database table is locked (6)" when a table is in use
+        // when a checkpoint is attempted. We don't have table locks, so return TableLocked for any
+        // attempt to checkpoint in an interactive transaction. This does not end the transaction,
+        // however.
+        return Err(LimboError::TableLocked);
+    }
     let result = program.connection.checkpoint(*checkpoint_mode);
     match result {
         Ok(CheckpointResult {

core/vdbe/mod.rs

@@ -757,7 +757,10 @@ pub fn handle_program_error(
     err: &LimboError,
 ) -> Result<()> {
     match err {
+        // Transaction errors, e.g. trying to start a nested transaction, do not cause a rollback.
         LimboError::TxError(_) => {}
+        // Table locked errors, e.g. trying to checkpoint in an interactive transaction, do not cause a rollback.
+        LimboError::TableLocked => {}
         _ => {
             let state = connection.transaction_state.get();
             if let TransactionState::Write { schema_did_change } = state {