[BUG] Can't empty collection with DeleteMany()

Version 5.0.3 on .NET CORE 3.1

Describe the bug I’m trying to empty my collection (all data should be removed). When trying to call the DeleteMany() it fails. I get an error (see stacktrace).

Code to Reproduce

using (var database = new LiteDatabase($"FileName=data.db"))
{
    var collection = database.GetCollection<Photo>();
    collection.DeleteMany(_ => true);
}

Expected behavior Collection should be made empty

Screenshots/Stacktrace

LiteDB.LiteException: Expression '@p0' are not supported as predicate expression.
   at LiteDB.Engine.QueryOptimization.<SplitWherePredicateInTerms>g__add|7_0(BsonExpression predicate)
   at LiteDB.Engine.QueryOptimization.SplitWherePredicateInTerms()
   at LiteDB.Engine.QueryOptimization.ProcessQuery()
   at LiteDB.Engine.QueryExecutor.<>c__DisplayClass10_0.<<ExecuteQuery>g__RunQuery|0>d.MoveNext()
   at LiteDB.BsonDataReader..ctor(IEnumerable`1 values, String collection)
   at LiteDB.Engine.QueryExecutor.ExecuteQuery(Boolean executionPlan)
   at LiteDB.Engine.QueryExecutor.ExecuteQuery()
   at LiteDB.Engine.LiteEngine.Query(String collection, Query query)
   at LiteDB.Engine.LiteEngine.<>c__DisplayClass4_0.<<DeleteMany>g__getIds|1>d.MoveNext()
   at LiteDB.Engine.LiteEngine.<>c__DisplayClass3_0.<Delete>b__0(TransactionService transaction)
   at LiteDB.Engine.LiteEngine.AutoTransaction[T](Func`2 fn)
   at LiteDB.Engine.LiteEngine.Delete(String collection, IEnumerable`1 ids)
   at LiteDB.Engine.LiteEngine.<>c__DisplayClass4_0.<DeleteMany>b__0(TransactionService transaction)
   at LiteDB.Engine.LiteEngine.AutoTransaction[T](Func`2 fn)
   at LiteDB.Engine.LiteEngine.DeleteMany(String collection, BsonExpression predicate)
   at LiteDB.LiteCollection`1.DeleteMany(BsonExpression predicate)
   at LiteDB.LiteCollection`1.DeleteMany(Expression`1 predicate)

Additional context I also tried it with the following code without any success:

using (var database = Context.CreateDatabaseContext())
{
   var collection = database.GetCollection<Movie>();
   collection.DeleteMany(Query.All().Select);
}

[JensSchadron]

Hi @mregni,

This has been fixed in commit ed9382cd5a839169bbe636cd0166e45100a7c717, but it isn’t available yet in v5.0.3.

You can use this is a work-around for now though 🙂 collection.DeleteMany("1=1");

Assuming that this answers your question (for now), I’ll close this issue. If you feel like my answer is incomplete, or not completely answering your question, feel free to re-open it.

[JensSchadron]

Hi @mregni, just wanted to inform you that v5.0.4 has been released (which includes the fix for your issue)