Also, factor out a separate NewDataStoreWithRootTracker() since
the common case is to use the same value for both the ChunkStore
and the RootTracker.
Fixes#134
We've been keeping some special-case code in Datastore to handle the
situation where the Root of the store is nonexistent. There was some
checking for the empty Ref and creating a SetOfCommit out of whole
cloth. This meant that if you asked an empty Datastore (or Dataset)
what its Heads() were, it would give you back a Value that wasn't
backed by a Chunk in its underlying ChunkStore. This caused some
issues with pull code, so we decided to change things such that a
DataStore is primed with an initial empty SetOfCommit upon creation.
This means creating a Dataset in a DataStore now shows up in DataStore
history, which it did not before. Essentially, every Dataset now has
an "initial commit" of an empty SetOfCommit when it's created. I think
that having these show up as part of the DataStore history makes sense,
but the model may evolve over time.
The test for this does the following:
1. The generated code is checked in
2. Running the test regenerates the generated code
3. Then the test.go is compiled and run
This also adds a smoke test for the codegen which just makes sure
that we do not fail when we try to generate code.
Fixes#90
We want to be able to track individual datasets by name, so
that we can create pipelines that share the same datastore
but create unique views of the shared data.
Addresses issue #22
Rafael Weinstein