rename Core.BottomType => Core.TypeofBottom

[StefanKarpinski]

No description provided.

[tkelman]

wasn't exported, but would break JLD - https://github.com/JuliaIO/JLD.jl/blob/aced8cbe4c89712b48434e73d62ac96b582bf409/src/JLD.jl#L1039

add a non-exported deprecation?

[StefanKarpinski]

add a non-exported deprecation?

What about just fixing the one case where it's used, i.e. JLD.

[tkelman]

Possibly used in private or non-github code, and it's not like a deprecation is hard to add?

In order to still be able to benchmark against intermediate commits JLD will also have to account for both names at different versions.

[StefanKarpinski]

Adding a deprecation for an unexported, undocumented name that was added in this release and is used by only one package uses is silly.

[ararslan]

Out of curiosity, what's the motivation for the change?

[yuyichao]

This doesn't look right

julia> Core.BottomType == Type{Union{}}
false

julia> Core.BottomType === Type{Union{}}
false

[JeffBezanson]

#21023 fixes that (the == call at least).

[StefanKarpinski]

Yes, it's currently not true. Jeff and Jameson are having an ongoing debate about whether this should be true or not. Consider it aspirational.

[StefanKarpinski]

The motivation is that BottomType sounds like Union{} whereas this is the type of that, so calling it TypeofBottom seems considerably less confusing.

[ararslan]

macOS failure looks entirely unrelated

[StefanKarpinski]

@JeffBezanson: what do you think? Should I drop the docstring commit and then merge this?

[JeffBezanson]

I think this is ok. I would remove Type{Union{}} from the docstring but keep the rest, and also rename jl_bottomtype_type to jl_typeofbottom_type in src/.

[tkelman]

It's "silly" to add a single line to avoid hard-breaking a widely used package during feature freeze?

[tkelman]

either the old name should be deprecated or a fix to JLD (that keeps the ability for the package to work at versions that used the old name) should be staged, or this will be disruptive, break benchmarking and quite a few other packages

[StefanKarpinski]

PR created for JLD. Deprecating a binding in Core is not so simple, but you're welcome to take a crack at it.

that works. wonder why it wasn't written as typeof to begin with

[StefanKarpinski]

wonder why it wasn't written as typeof to begin with

Maybe because it wasn't entirely clear that Core.BottomType == typeof(Union{}) in the first place? Whoever wrote this may have wanted Type{Union{}} to work, but those are currently different.

[tkelman]

Jeff wrote it - JuliaIO/JLD.jl@1fa3929
though I think it was while the type system rewrite was still getting finished up, to get benchmarking working for it.

[StefanKarpinski]

In that case it's because he's probably used to referring to the type that way :)

[ararslan]

@nanosoldier runbenchmarks(ALL, vs=":master")

[nanosoldier]

Your benchmark job has completed - possible performance regressions were detected. A full report can be found here. cc @jrevels

[ararslan]

Cool, looks like Nanosoldier is ready, and the AV appears unrelated. Good to merge, I think.