Failed to build aarch64-apple-tvos target

[arttet]

I tried to build aarch64-apple-tvos, x86_64-apple-tvos, aarch64-apple-tvos-sim targets.
Unfortunately, I got

the following errors:

  error: methods `as_raw_stat`, `st_birthtime`, `st_birthtime_nsec`, `st_flags`, `st_gen`, and `st_lspare` are never used
    --> library/std/src/os/ios/fs.rs:29:8
     |
  15 | pub trait MetadataExt {
     |           ----------- methods in this trait
  ...
  29 |     fn as_raw_stat(&self) -> &raw::stat;
     |        ^^^^^^^^^^^
  ...
  60 |     fn st_birthtime(&self) -> i64;
     |        ^^^^^^^^^^^^
  61 |     #[stable(feature = "metadata_ext2", since = "1.8.0")]
  62 |     fn st_birthtime_nsec(&self) -> i64;
     |        ^^^^^^^^^^^^^^^^^
  ...
  68 |     fn st_flags(&self) -> u32;
     |        ^^^^^^^^
  69 |     #[stable(feature = "metadata_ext2", since = "1.8.0")]
  70 |     fn st_gen(&self) -> u32;
     |        ^^^^^^
  71 |     #[stable(feature = "metadata_ext2", since = "1.8.0")]
  72 |     fn st_lspare(&self) -> u32;
     |        ^^^^^^^^^
     |
     = note: `-D dead-code` implied by `-D warnings`
     = help: to override `-D warnings` add `#[allow(dead_code)]`
  
  error: method `set_created` is never used
     --> library/std/src/os/ios/fs.rs:151:8
      |
  148 | pub trait FileTimesExt: Sealed {
      |           ------------ method in this trait
  ...
  151 |     fn set_created(self, t: SystemTime) -> Self;
      |        ^^^^^^^^^^^
  
  
  Did not run successfully: exit status: 1

How to reproduce

./configure \
		--enable-option-checking \
		--tools=cargo,clippy,rustdoc,rustfmt,rust-analyzer,analysis,src \
		--target=aarch64-apple-tvos,x86_64-apple-tvos,aarch64-apple-tvos-sim \
		--set llvm.download-ci-llvm=true \
		--set build.verbose=1 \
		--set rust.channel=dev \
		--dist-compression-formats=xz \
		--prefix=install

According to the docs, the target maintainer is @thomcc

[saethlin]

I think you can just add --set rust.deny-warnings=false. Those look like warnings that are treated as errors in the default config.

The code still needs maintenance, but maybe that unblocks you.

[Rajveer100]

@saethlin
Can you describe a bit about this?

[saethlin]

tvos is a tier 3 target, which means that it may not have any CI. In this case, it looks like it doesn't. The support tiers are documented and explained here: https://doc.rust-lang.org/nightly/rustc/platform-support.html

The default build configuration used by x.py, the bootstrap entrypoint, is to build the compiler and library with -Dwarnings. We have an option to turn this off, i.e. to treat warnings as warnings. The person who reported this issue is not actually encountering a bug, they are just tripping over an unfortunate default. Building the library and compiler with x.py is primarily intended for developers of the compiler and standard library, not for end users. We deny warnings in CI, so the default dev setup matches CI.

If you want to use the tvos targets, they build perfectly fine using -Zbuild-std, which should be the normal way to use a Tier 3 target: cargo +nightly build -Zbuild-std --target=aarch64-apple-tvos will locally build the standard library for the aarch64 tvOS target. The distributed rustc is a cross-compiler that supports all our targets, you never need to rebuild the compiler in order to use any of the built-in targets, meaning the contents of rustc +nightly --print target-list.

Is there something more specific you want to know?

[Rajveer100]

What's your suggestion in terms of fixing this issue?

[saethlin]

add --set rust.deny-warnings=false

As I said above.

Alternatively, you could contribute the rest of the tvos std implementation.

[Rajveer100]

Can you describe a bit about this?

@saethlin
I was actually asking in terms of opening a PR for this, what's the way to go about this?

[saethlin]

Oh, are you asking because I labeled this easy 🤦

Actually making these functions used is not easy, and probably amounts to "finish the TvOS support". What I was thinking of then was that OP needs to add the flag I mentioned above, and that wherever they got that command needs to be adjusted.

[Rajveer100]

Well, no worries although I would still be happy to contribute if you think it's approachable despite it not being a good-first-issue.

[saethlin]

It's approachable, but would be best done with some advice from the target maintainer, @thomcc: It looks like a bunch of filesystem metadata functions are unused in the tvos target. Is there missing implementation? Whats' the general strategy for finishing the implementation up?