Tons of unexpected_cfgs failures in portable-simd and backtrace doctests

@Urgau

Running std doctests in Miri results in tons of errors since today's nightly:

  0.000010   ---- library/core/src/../../portable-simd/crates/core_simd/src/vector.rs - core_simd::vector::Simd<T,N>::store_select (line 640) stdout ----
  0.000008   error: unexpected `cfg` condition value: `as_crate`
  0.000010    --> library/core/src/../../portable-simd/crates/core_simd/src/vector.rs:642:7
  0.000008     |
  0.000011   5 | #[cfg(feature = "as_crate")] use core_simd::simd;
  0.000010     |       ^^^^^^^^^^^^^^^^^^^^
  0.000011     |
  0.000013     = note: expected values for `feature` are: `debug_refcell`, `panic_immediate_abort`
  0.000007     = help: consider adding `as_crate` as a feature in `Cargo.toml`
  0.000011     = note: see <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg> for more information about checking conditional configuration
  0.000007   note: the lint level is defined here
  0.000010    --> library/core/src/../../portable-simd/crates/core_simd/src/vector.rs:638:9
  0.000008     |
  0.000010   1 | #![deny(warnings)]
  0.000008     |         ^^^^^^^^
  0.000010     = note: `#[deny(unexpected_cfgs)]` implied by `#[deny(warnings)]`
  0.000010   
  0.000010   error: unexpected `cfg` condition value: `as_crate`
  0.000008    --> library/core/src/../../portable-simd/crates/core_simd/src/vector.rs:643:11
  0.000010     |
  0.000008   6 | #[cfg(not(feature = "as_crate"))] use core::simd;
  0.000010     |           ^^^^^^^^^^^^^^^^^^^^
  0.000008     |
  0.000010     = note: expected values for `feature` are: `debug_refcell`, `panic_immediate_abort`
  0.000008     = help: consider adding `as_crate` as a feature in `Cargo.toml`
  0.000011     = note: see <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg> for more information about checking conditional configuration
  0.000009   
  0.000010   error: aborting due to 2 previous errors
  0.000008   
  0.000010   Couldn't compile the test.

Interestingly, the in-tree test suite is working, so there's likely some special bootstrap magic somewhere that out-of-tree tests do not benefit from?

cc @Urgau

These files are from portable-simd, which means they are sometimes their own crate and sometimes a module imported into core. There is indeed no as_crate feature in core, so no idea how these tests are passing in our CI.

Do we inject a -A unexpected_cfgs somewhere for doctests, or something like that?

There's also one in std, from the backtrace module, which similarly is also sometimes a crate and sometimes a module:

  0.000008   ---- library/std/src/../../backtrace/src/lib.rs - backtrace_rs (line 20) stdout ----
  0.000007   error: unexpected `cfg` condition value: `std`
  0.000007    --> library/std/src/../../backtrace/src/lib.rs:23:7
  0.000008     |
  0.000007   5 | #[cfg(feature = "std")] {
  0.000008     |       ^^^^^^^^^^^^^^^
  0.000007     |
  0.000008     = note: expected values for `feature` are: `addr2line`, `backtrace`, `compiler-builtins-c`, `compiler-builtins-mangled-names`, `compiler-builtins-mem`, `compiler-builtins-no-asm`, `compiler-builtins-weak-intrinsics`, `llvm-libunwind`, `miniz_oxide`, `object`, `panic-unwind`, `panic_immediate_abort`, `panic_unwind`, `profiler`, `profiler_builtins`, `std_detect_dlsym_getauxval`, `std_detect_env_override`, `std_detect_file_io`, `system-llvm-libunwind`
  0.000008     = help: consider adding `std` as a feature in `Cargo.toml`
  0.000007     = note: see <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg> for more information about checking conditional configuration
  0.000007   note: the lint level is defined here
  0.000007    --> library/std/src/../../backtrace/src/lib.rs:19:9
  0.000007     |
  0.000007   1 | #![deny(warnings)]
  0.000007     |         ^^^^^^^^
  0.000007     = note: `#[deny(unexpected_cfgs)]` implied by `#[deny(warnings)]`
  0.000008   
  0.000007   error: aborting due to 1 previous error
  0.000007   
  0.000007   Couldn't compile the test.

Huh.

It's quite possible that this is caused by the CI mess. One of the insta-merged PRs was a miri sync.

It's possible but seems unlikely to me. I guess we'll have to see.

Interestingly, the in-tree test suite is working, so there's likely some special bootstrap magic somewhere that out-of-tree tests do not benefit from?

Yes, there is,

rust/src/bootstrap/src/core/builder.rs

Lines 1545 to 1555 in 69ffc0d

    
           // Enable compile-time checking of `cfg` names, values and Cargo `features`. 
        
           // 
        
           // Note: `std`, `alloc` and `core` imports some dependencies by #[path] (like 
        
           // backtrace, core_simd, std_float, ...), those dependencies have their own 
        
           // features but cargo isn't involved in the #[path] process and so cannot pass the 
        
           // complete list of features, so for that reason we don't enable checking of 
        
           // features for std crates. 
        
           cargo.arg("-Zcheck-cfg"); 
        
           if mode == Mode::Std { 
        
               rustflags.arg("--check-cfg=cfg(feature,values(any()))"); 
        
           }

I would suggest doing the same and adding as part of the build --check-cfg=cfg(feature,values(any())), possibly in RUSTFLAGS or somewhere else.

That seems to help, thanks. :)

Another thing we could do now that check-cfg is stable, is adding this exception directly in the build.rs of core, alloc and std with the Cargo instruction cargo::rustc-check-cfg.

If you end up doing that, please ping me so I can revert rust-lang/miri-test-libstd#66.

@RalfJung

@RalfJung I don't think allowing all values for the feature cfg is going to be enough. There are many other custom cfgs used in core/alloc/std,

rust/src/bootstrap/src/lib.rs

Lines 87 to 97 in 69ffc0d

    
           (Some(Mode::Std), "stdarch_intel_sde", None), 
        
           (Some(Mode::Std), "no_fp_fmt_parse", None), 
        
           (Some(Mode::Std), "no_global_oom_handling", None), 
        
           (Some(Mode::Std), "no_rc", None), 
        
           (Some(Mode::Std), "no_sync", None), 
        
           (Some(Mode::Std), "netbsd10", None), 
        
           (Some(Mode::Std), "backtrace_in_libstd", None), 
        
           /* Extra values not defined in the built-in targets yet, but used in std */ 
        
           (Some(Mode::Std), "target_env", Some(&["libnx", "p2"])), 
        
           (Some(Mode::Std), "target_os", Some(&["visionos"])), 
        
           (Some(Mode::Std), "target_arch", Some(&["arm64ec", "spirv", "nvptx", "xtensa"])),

In fact I can see them in the latest CI run under the "Setup environment". If you want to completely silence them, allowing the lint (-Aunexpected_cfgs in RUSTFLAGS) is probably (in the short term) the best course of action.

This was enough though to make the tests pass again... 🤷

Oh, they are shown as warning, not hard errors.

Sure, I can also allow the lint entirely.

Actually, those warnings come from the sysroot build, not the local test build. So this will need a patch in https://github.com/RalfJung/rustc-build-sysroot/ . Also, -Aunexpected_cfgs does not help for the doctests, for some reason.

(FWIW, debugging rustc invocations became a lot harder when they all grew to more than twice their size due to all these --check-cfg flags. If there's any way to hide these flags e.g. in argument files or so, that would be great...)

@RalfJung

If you end up doing that, please ping me so I can revert rust-lang/miri-test-libstd#66.

@RalfJung We did add the corresponding --check-cfg args to std, alloc and core in #125296

(FWIW, debugging rustc invocations became a lot harder when they all grew to more than twice their size due to all these --check-cfg flags. If there's any way to hide these flags e.g. in argument files or so, that would be great...)

We are tracking this in rust-lang/cargo#13941

We did add the corresponding --check-cfg args to std, alloc and core in #125296

Awesome, that seems to be enough for miri-test-libstd as well. :)

Navigation Menu

Repository navigation

Tons of `unexpected_cfgs` failures in portable-simd and backtrace doctests #124740

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

	// Enable compile-time checking of `cfg` names, values and Cargo `features`.
	//
	// Note: `std`, `alloc` and `core` imports some dependencies by #[path] (like
	// backtrace, core_simd, std_float, ...), those dependencies have their own
	// features but cargo isn't involved in the #[path] process and so cannot pass the
	// complete list of features, so for that reason we don't enable checking of
	// features for std crates.
	cargo.arg("-Zcheck-cfg");
	if mode == Mode::Std {
	rustflags.arg("--check-cfg=cfg(feature,values(any()))");
	}

	(Some(Mode::Std), "stdarch_intel_sde", None),
	(Some(Mode::Std), "no_fp_fmt_parse", None),
	(Some(Mode::Std), "no_global_oom_handling", None),
	(Some(Mode::Std), "no_rc", None),
	(Some(Mode::Std), "no_sync", None),
	(Some(Mode::Std), "netbsd10", None),
	(Some(Mode::Std), "backtrace_in_libstd", None),
	/* Extra values not defined in the built-in targets yet, but used in std */
	(Some(Mode::Std), "target_env", Some(&["libnx", "p2"])),
	(Some(Mode::Std), "target_os", Some(&["visionos"])),
	(Some(Mode::Std), "target_arch", Some(&["arm64ec", "spirv", "nvptx", "xtensa"])),

Tons of unexpected_cfgs failures in portable-simd and backtrace doctests #124740

Description

Activity

RalfJung commented on May 5, 2024

RalfJung commented on May 5, 2024

workingjubilee commented on May 5, 2024

Kobzol commented on May 5, 2024

RalfJung commented on May 5, 2024

Urgau commented on May 5, 2024

RalfJung commented on May 5, 2024

Urgau commented on May 5, 2024

RalfJung commented on May 5, 2024

Urgau commented on May 5, 2024

RalfJung commented on May 5, 2024

RalfJung commented on May 5, 2024

RalfJung commented on May 5, 2024

Urgau commented on May 22, 2024

RalfJung commented on May 23, 2024

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Tons of `unexpected_cfgs` failures in portable-simd and backtrace doctests #124740