Cargo warning about publish-lockfile feature when compiling

[luojia65]

Hello! When I test an handwritten OS following the toturial Writing an OS in Rust, the test is successful, but there is a warning on configuration when building the bootloader. Here's my console output:

PS D:\RustProjects\spicy_os> cargo xtest
   Compiling spicy_os v0.1.0 (D:\RustProjects\spicy_os)
    Finished dev [unoptimized + debuginfo] target(s) in 0.38s
     Running target\x86_64-spicy_os\debug\deps\spicy_os-990499773c553c1e
Building bootloader
warning: The `publish-lockfile` feature is deprecated and currently has no effect. It may be removed in a future version.
   Compiling bootloader v0.6.0 (C:\Users\luojia65\.cargo\registry\src\mirrors.ustc.edu.cn-61ef6e0cd06fb9b8\bootloader-0.6.0)
    Finished release [optimized + debuginfo] target(s) in 1.88s
Running: `qemu-system-x86_64 -drive format=raw,file=D:\RustProjects\spicy_os\target\x86_64-spicy_os\debug\deps\bootimage-spicy_os-990499773c553c1e.bin -device isa-debug-exit,iobase=0xf4,iosize=0x04 -serial stdio -display none

According to this warning, cargo feature publish-lockfile has currently no effect. It looks like this is related to the piece of code here. Would it be possible to remove this cargo feature configuration, or do another way to fix this warning?

Here's my Rustup and Rustc version:

C:\Users\luojia65>rustup -V
rustup 1.18.3 (435397f48 2019-05-22)

C:\Users\luojia65>rustc -V
rustc 1.35.0 (3c235d560 2019-05-20)

[phil-opp]

Thanks for reporting! The publish-lockfile feature was recently removed in rust-lang/cargo#7026. So yes, removing the cargo feature should fix the warning. However, I think we should wait for a bit (about a week or so) before removing the feature to give people that rely on the publish-lockfile feature time to update their nightlies.