Crashed precompile damages default system image

[DeanLym]

I ran into this problem when a precompiling process crashed, the default system image will be damaged. There is no sys.dll.backup file available. It seems to me that the backup default system image is generated in the last step. In this case if the precompiling crashed, there will be no default system image.

[KristofferC]

Hm, that's not intended. The intention is to create the sysimage in a temporary location:

PackageCompiler.jl/src/PackageCompiler.jl

Lines 392 to 393 in 69f556a

	tmp = mktempdir()
	sysimage_path = joinpath(tmp, string("sys.", Libdl.dlext))

and only in the end move it to the correct location:

PackageCompiler.jl/src/PackageCompiler.jl

Lines 441 to 445 in 69f556a

	if !isfile(backup_default_sysimg_path())
	@debug "making a backup of default sysimg"
	cp(default_sysimg_path(), backup_default_sysimg_path())
	end
	move_default_sysimage_if_windows()

The replacement of the old sysimage should only be done after the backup is created. Not sure what is going wrong.

[KristofferC]

replace_default is not recommended and will probably get removed (#546). Since issues with it are known, I'll close this.