# Objective
Fixes#7702.
## Solution
- Added an test that ensures that no error is returned if a system or set is inside two different sets that share the same base set.
- Added an check to only return an error if the two base sets are not equal.
# Objective
The `ScheduleGraph` should be expose so that crates like [bevy_mod_debugdump](https://github.com/jakobhellermann/bevy_mod_debugdump/blob/stageless/docs/README.md) can access useful information.
## Solution
- expose `ScheduleGraph`, `NodeId`, `BaseSetMembership`, `Dag`
- add accessor functions for sets and systems
## Changelog
- expose `ScheduleGraph` for use in third party tools
This does expose our use of `petgraph` as a graph library, so we can only change that as a breaking change.
* Add mutated tracker on resources and ChangedRes query for added or mutated resources.
* ResMut:::new() now takes a reference to a 'mutated' flag in its archetype.
* Change FetchResource so that get() returns an Option. Systems using Resources will only be called if all fetched Resources are Some(). This is done to implement ChangedRes, which is Some iff the Resource has been changed.
* Add OrRes for a logical or in tuples of Resource queries.
* Separate resource query get() in is_some() and get() methods for clarity
* Remove unneeded unsafe
* Change ResMut::new()
