sequence.getOffset was problematic and didn't have a clear meaning. In addition it was causing a bunch of +1 code at call sites. This patch replaces it with cumulativeNumLeaves which has a clearer meaning.
This changes so that all commit struct types have a meta field
(which might be an empty struct).
Increment the serialization version since the old data does not
necessarily have the meta field.
Fixes ##2112
We now compute the commit type based on the type of the value and
the type of the parents.
For the first commit we get:
```
struct Commit {
parents: Set<Ref<Cycle<0>>>,
value: T,
}
```
As long as we continue to commit values with type T that type stays
the same.
When we later commits a value of type U we get:
```
struct Commit {
parents: Set<Ref<struct Commit {
parents: Set<Ref<Cycle<0>>>,
value: T | U
}>>,
value: U,
}
```
The new type gets combined as a union type for the value of the inner
commit struct.
Fixes#1495
* Revert "Revert "Share node_modules for samples/js" (#1967)"
This reverts commit 7bb1623e99.
* Add parent directory to the PATH
* Change run-all-js-tests to run samples/js before samples/js/**
* Fix a temporary comment
Previously when we had an ordered (set/map) prolly tree containing
non-ordered values (blobs/refs/etc), we'd put the ref of the largest
value in each meta node, complete with its full type info and height.
This is wasteful, all we really need is the hash of the largest item for
searching the tree. In lieu of encoding just the hash - which isn't a
value - this patch creates a fake Ref<Boolean> with height 0.
In Go: there are already similar tests for numbers, but testing structs
hits the non-scalar value prolly tree code.
In JS: the set and map tests hadn't even been ported from Go, so I
ported most of their functionality.
There were a few issues here:
1. The version header was not always passed to fetch
2. HTTP headers are case insensitive and Node an Fetch uses lower case.
3. The old code used a Map instead of an object as map. Node and Fetch
uses an object as map. Now we just pass along the response headers.
Fixes#1881Closes#1880 (which this is partially based in)
ChunkStores provide a Version() method so that anyone directly
using a ChunkStore (e.g. BatchStoreAdaptor) can retrieve and
check the version of the underlying store.
remoteDatabaseServer checks the version of the ChunkStore it's
backed by at startup, and then provides that version as an HTTP
header to all clients. In Go, httpBatchStore checks this header
anytime it gets a response from the server and bails if there's
version skew.
In Go, the responsibility for checking whether the running code and
the data being accessed lies with the BatchStore layer. In JS, there
is code in fetch.js that checks the header mentioned above.
Towards #1561
Fix sequence chunker bug triggered by repeatedly removing last element
The bug is we sometimes create a prollytree with a root meta sequence
node with only a single item. This is never the canonical representation
of prollytrees.
I reworked the sequence chunker to take a different approach to corner
cases. Instead of being smart and avoiding this case (which clearly
didn't work properly), it's more liberal with creating unnecessary
nodes, then it fixes them up in the finalisation step.
Erik Arvidsson