try keep old behaviror for 🍎

stdlib/Mmap/src/Mmap.jl

@@ -210,8 +210,10 @@ function mmap(io::IO,
  file_desc = gethandle(io)
  szfile = convert(Csize_t, len + offset)
  requestedSizeLarger = false
- if !(io isa Mmap.Anonymous || Sys.isapple())
- requestedSizeLarger = szfile > filesize(io)
+ if !(io isa Mmap.Anonymous)
+ @static if !Sys.isapple()
+ requestedSizeLarger = szfile > filesize(io)
+ end
  end
  # platform-specific mmapping
  @static if Sys.isunix()
@@ -227,6 +229,9 @@ function mmap(io::IO,
  throw(ArgumentError("unable to increase file size to $szfile due to read-only permissions"))
  end
  end
+ @static if Sys.isapple()
+ iswrite && grow && grow!(io, offset, len)
+ end
  # mmap the file
  ptr = ccall(:jl_mmap, Ptr{Cvoid}, (Ptr{Cvoid}, Csize_t, Cint, Cint, RawFD, Int64),
  C_NULL, mmaplen, prot, flags, file_desc, offset_page)