[RUST] ci_cpu docker image build failure.

[ghost]

The ci_cpu docker image fails to build cleanly. The Dockerfile runs ubuntu_install_rust.sh which in turn executes:
cargo +nightly install rustfmt-nightly --version 1.0.1 --force

Which results in the following build error:

ubuntu_install_rust.sh
^[[0m^[[91m Compiling scoped-tls v0.1.2
^[[0m^[[91merror[E0277]: the trait bound std::borrow::Cow<'_, str>: std::convert::From<core::str::EscapeDefault<'_>> is not satisfied^[[0m^[[91m
^[[0m^[[91m --> /opt/rust/registry/src/github.com-1ecc6299db9ec823/rustc-ap-graphviz-306.0.0/lib.rs:551:44^[[0m^[[91m
^[[0m^[[91m |^[[0m^[[91m
^[[0m^[[91m551 | (&*s).escape_default().into()^[[0m^[[91m
^[[0m^[[91m | ^^^^ the trait std::convert::From<core::str::EscapeDefault<'_>> is not implemented for std::borrow::Cow<'_, str>^[[0m^[[91m
^[[0m^[[91m |^[[0m^[[91m
^[[0m^[[91m = help: the following implementations were found:^[[0m^[[91m
^[[0m^[[91m <std::borrow::Cow<'a, [T]> as std::convert::From<&'a [T]>>^[[0m^[[91m
^[[0m^[[91m <std::borrow::Cow<'a, [T]> as std::convert::From<&'a std::vec::Vec>>^[[0m^[[91m
^[[0m^[[91m <std::borrow::Cow<'a, [T]> as std::convert::From<std::vec::Vec>>^[[0m^[[91m
^[[0m^[[91m <std::borrow::Cow<'a, std::ffi::CStr> as std::convert::From<&'a std::ffi::CStr>>^[[0m^[[91m
^[[0m^[[91m and 11 others^[[0m^[[91m
^[[0m^[[91m = note: required because of the requirements on the impl of std::convert::Into<std::borrow::Cow<'_, str>> for core::str::EscapeDefault<'_>^[[0m^[[91m
^[[0m^[[91m
^[[0m^[[91merror: aborting due to previous error^[[0m^[[91m
^[[0m^[[91m
^[[0m^[[91mFor more information about this error, try rustc --explain E0277.^[[0m^[[91m
^[[0m^[[91merror: Could not compile rustc-ap-graphviz.
warning: build failed, waiting for other jobs to finish...
^[[0m^[[91merror: failed to compile rustfmt-nightly v1.0.1, intermediate artifacts can be found at /tmp/cargo-installgw3Wp4

[tqchen]

cc @nhynes can you help to take a look?

[nhynes]

Huh. I don't think anything changed in rust/ lately. Maybe a dependency was a missing lockfile somewhere. Isn't semver great? I'll take a look now.

[tqchen]

I can confirm there is an error locally, was due to a deleted version tag in /opt/rust/sgx , perhaps in upstream

[ghost]

@tqchen can you elaborate a little more detail on the tag you mention above?

[nhynes]

I'm working on this literally right now. I'll post back shortly! Super sorry for the long delay.

[nhynes]

Ehh. This one was an unfortunate case of rust nightly being unstable (go figure). rustfmt 1.0.1 used APIs that changed since the nightly with which it was originally built. Fortunately, the fix is simple. Thanks for reporting this!