DataType's mutable field removal: put in NEWS.md or unintentional?

[daviehh]

Up to the current 1.6.1 version, DataTypes have a mutable field

julia> Int.mutable
false

which seems to have gone in the 1.7 master branch:

julia> Int.mutable
ERROR: type DataType has no field mutable
Stacktrace:
 [1] getproperty(x::Type, f::Symbol)
   @ Base ./Base.jl:28
 [2] top-level scope
   @ REPL[1]:1

This has caused, e.g. BSON.jl to fail due to https://github.com/JuliaIO/BSON.jl/blob/ecae1169be8fb20a88ed2d23417e8585e4a2a7fe/src/write.jl#L46

Is this change intentional (in which case this should probably put into NEWS.md/provide a current way to check if certain type is mutable via ismutabletype)?

julia versioninfo():

Julia Version 1.7.0-DEV.1222
Commit 4a8572fc6d (2021-06-01 18:02 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin20.5.0)
  CPU: Intel(R) Core(TM) i5-8259U CPU @ 2.30GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.0 (ORCJIT, skylake)
Environment:
  JULIA_MATHLINK = /Applications/Mathematica.app/Contents/Frameworks/mathlink.framework
  JULIA_MATHKERNEL = /Applications/Mathematica.app/Contents/MacOS/MathKernel

[KristofferC]

Is this change intentional (in which case this should probably put into NEWS.md/provide a current way to check if certain type is mutable)?

Changes to internals are typically not given a NEWS entry. People that use them are sort of expected to be able to look up what happened to it and how to fix their code.

[vtjnash]

I guess "people" in this case is Jeff 😂 JuliaIO/BSON.jl#63

[imciner2]

In 1.5+ there is a function ismutable that should give you the information you want about type mutability, so you could replace T.mutable with ismutable(T) in 1.5+.

[JeffBezanson]

ismutabletype

[daviehh]

Thanks for the info!