Multi dimensional arrays are not flattened into 1-D arrays when using
TypeGraph. Update TreeBuilder to account for this.
By not flattening arrays, we are able to produce more descriptive
results.
The disadvantage is that we must now recurse inside arrays
containing only primitives. A better solution to requiring flattening
would be the planned work to not recurse into any static types (not just
primitives). This would also apply to multi-dimensional arrays of
primtivies.
When we were previously removing allocators, we were only able to work
with containers whose allocators appeared as their last template
parameter.
Now we can replace allocators in the middle of a parameter list.
This fixes tests for folly::sorted_vector_set.
This is necessary when replacing the allocator of a map type, for
example.
`std::map<int, int>` will need an allocator which allocates elements of
type `std::pair<const int, int>>`
std::basic_string takes three template parameters:
1. CharT
2. Traits
3. Allocator
The Traits parameter was causing issues, as it requires a type which
exposes certain things, e.g. `Traits::value_type`.
We have a few options to resolve this:
1. Remove this parameter, as we do for allocators
Cons: removing a template parameter doesn't work if other
parameters appear after it
2. Stub this parameter, as we do for hashers/comparators
Cons: we need to hardcode an implementation that satisfies the
`Traits::value_type` requirements
3. Leave the parameter as-is
Cons: will not work if a non-standard Traits is used
By using the real implementation of this Traits parameter
(normally `std::char_traits<CharT>`), we get one that we know will
work as long as it is defined in a stdlib header.
Option 3 is what we use in this patch. Instead of adding more
configuration options to the container TOML file format (e.g.
`params_to_keep = [1]`), we add `std::char_traits` as a dummy
container type. Now, whenever `std::char_traits` appears, it will be
left as-is, i.e. not removed, replaced or reverse-engineered.
This is the same approach previously used for Thrift's isset_bitset.
It was previously easy to miss modules and I haven't been able to notice
any difference in behaviour when setting the VLOG level globally
(despite what the old comment says).
Previously we had an `R"(` string in `OITraceCode.cpp` which allowed us
to include the file as a string. Instead, keep `OITraceCode.cpp` a fully
formed C++ file and utilise the build system to turn it into a string.
This will be used for more header files that are needed both as valid
headers and as strings for JIT compilation in the Typed TreeBuilder
work.
