Rust building and testing fails while bootstrapping it in poky

[Yashinde145]

Getting error while building & testing rust 1.72 via the src/bootstrap/bootstrap.py file in poky (cmd- bitbake rust and then python3 src/bootstrap/bootstrap.py test test_suites_names --target x86_64-poky-linux-gnu)in poky environment. Until rust 1.70 I was able to build & test the rust sources successfully.
But after updating to rust 1.72, there's an assertion failure causing the problem. The rust build fails as follows-

Note that not all variants of mir-opt tests are going to be blessed, as no mapping between a 
32bit and a 64bit target was found for x86_64-poky-linux-gnu.
You can add that mapping by changing MIR_OPT_BLESS_TARGET_MAPPING in src/bootstrap/test.rs
thread 'main' panicked at 'assertion failed: `(left == right)`
  left: `x86_64-unknown-linux-gnu`,
 right: `x86_64-poky-linux-gnu`: Cannot obtain compiler for non-native build triple at stage 0', compile.rs:1474:13

The code at compile.rs:1474

1470     fn run(self, builder: &Builder<'_>) -> Compiler {
1471         let target_compiler = self.target_compiler;
1472 
1473         if target_compiler.stage == 0 {
1474             assert_eq!(
1475                 builder.config.build, target_compiler.host,
1476                 "Cannot obtain compiler for non-native build triple at stage 0"
1477             );
1478             // The stage 0 compiler for the build triple is always pre-built.
1479             return target_compiler;
1480         }

Build terminates as follows-

test [mir-opt] tests/mir-opt/reference_prop.rs ... ok
test [mir-opt] tests/mir-opt/inline/polymorphic_recursion.rs ... ok
test result: ok. 249 passed; 0 failed; 13 ignored; 0 measured; 0 filtered out; finished in 1.39s

error: the option `Z` is only accepted on the nightly compiler
note: selecting a toolchain with `+toolchain` arguments require a rustup proxy; see <https://rust-lang.github.io/rustup/concepts/index.html>
help: consider switching to a nightly toolchain: `rustup default nightly`
note: for more information about Rust's stability policy, see <https://doc.rust-lang.org/book/appendix-07-nightly-rust.html#unstable-features>
thread 'main' panicked at 'failed to gather the target spec for i686-unknown-linux-gnu', synthetic_targets.rs:66:9
Build completed unsuccessfully in 0:05:27

Version it worked on

It most recently worked on Rust 1.70 and earlier versions

Version with regression

Rust 1.72

Backtrace

Backtrace

stack backtrace:                                                                                                                                                                                                
   0: rust_begin_unwind                                                                                                                                                                                         
             at /rustc/8ede3aae28fe6e4d52b38157d7bfe0d3bceef225/library/std/src/panicking.rs:593:5                                                                                                              
   1: core::panicking::panic_fmt                                                                                                                                                                                
             at /rustc/8ede3aae28fe6e4d52b38157d7bfe0d3bceef225/library/core/src/panicking.rs:67:14                                                                                                             
   2: core::panicking::assert_failed_inner                                                                                                                                                                      
   3: core::panicking::assert_failed                                                                                                                                                                            
             at /rustc/8ede3aae28fe6e4d52b38157d7bfe0d3bceef225/library/core/src/panicking.rs:228:5                                                                                                             
   4: <bootstrap::compile::Assemble as bootstrap::builder::Step>::run                                                                                                                                           
             at ./src/bootstrap/compile.rs:1474:13                                                                                                                                                              
   5: bootstrap::builder::Builder::ensure                                                                                                                                                                       
             at ./src/bootstrap/builder.rs:2055:23                                                                                                                                                              
   6: bootstrap::builder::Builder::compiler                                                                                                                                                                     
             at ./src/bootstrap/builder.rs:943:9                                                                                                                                                                
   7: <bootstrap::test::Compiletest as bootstrap::builder::Step>::run                                                                                                                                           
             at ./src/bootstrap/test.rs:1462:24                                                                                                                                                                 
   8: bootstrap::builder::Builder::ensure                                                                                                                                                                       
             at ./src/bootstrap/builder.rs:2055:23                                                                                                                                                              
   9: <bootstrap::test::UiFullDeps as bootstrap::builder::Step>::run                                                                                                                                            
             at ./src/bootstrap/test.rs:1260:17                                                                                                                                                                 
  10: bootstrap::builder::Builder::ensure                                                                                                                                                                       
             at ./src/bootstrap/builder.rs:2055:23                                                                                                                                                              
  11: <bootstrap::test::UiFullDeps as bootstrap::builder::Step>::make_run                                                                                                                                       
             at ./src/bootstrap/test.rs:1256:17                                                                                                                                                                 
  12: bootstrap::builder::StepDescription::maybe_run                                                                                                                                                            
             at ./src/bootstrap/builder.rs:278:13                                                                                                                                                               
  13: bootstrap::builder::StepDescription::run                                                                                                                                                                  
             at ./src/bootstrap/builder.rs:315:21                                                                                                                                                               
  14: bootstrap::builder::Builder::run_step_descriptions                                                                                                                                                        
             at ./src/bootstrap/builder.rs:935:9                                                                                                                                                                
  15: bootstrap::builder::Builder::execute_cli                                                                                                                                                                  
             at ./src/bootstrap/builder.rs:916:9                                                                                                                                                                
  16: bootstrap::Build::build                                                                                                                                                                                   
             at ./src/bootstrap/lib.rs:697:17                                                                                                                                                                   
  17: bootstrap::main                                                                                                                                                                                           
             at ./src/bootstrap/bin/main.rs:74:5                                                                                                                                                                
  18: core::ops::function::FnOnce::call_once                                                                                                                                                                    
             at /rustc/8ede3aae28fe6e4d52b38157d7bfe0d3bceef225/library/core/src/ops/function.rs:250:5                                                                                                          
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.                                                                                                                         
Build completed unsuccessfully in 0:00:20


<!--
@rustbot modify labels: +regression-from-stable-to-{stable} -regression-untriaged 

[Noratrieb]

I believe MIR_OPT_BLESS_TARGET_MAPPING is unrelated to the issue you're seeing, but I'm not sure.

[Yashinde145]

Yeah, I guess the assertion failure is main cause.
Why the two strings are different though? Until rust 1.70, I didn't faced this assertion failure(diff in builder.config.build i.e left: x86_64-unknown-linux-gnu, and target_compiler.host i.e right: x86_64-poky-linux-gnu). When did git blame for these lines, found that this code was present (from 5 years i.e 2018)even in the earlier rust versions.

[apiraino]

Adding useful labels for triaging

@rustbot label -I-prioritize +T-bootstrap -needs-triage

[onur-ozkan]

I couldn't reproduce this problem from the e39976f HEAD.

The assertation passes as expected(on `./x test bootstrap --target=..), I also printed them out.

The diff:

Sorry for sharing the the outputs in the image format; the attempt was done inside of QEMU(Debian 11).

[Yashinde145]

Thanks for checking @onur-ozkan,
But, my build shows following-
Note- The targets are printed 3 times and the assertion fails in the 3rd call

Compiling clap v4.2.4
   Compiling clap_complete v4.2.2
    Finished dev [unoptimized] target(s) in 20.26s

builder.config.build = x86_64-unknown-linux-gnu
target_compiler.host = x86_64-unknown-linux-gnu
builder.config.build = x86_64-unknown-linux-gnu
target_compiler.host = x86_64-unknown-linux-gnu
builder.config.build = x86_64-unknown-linux-gnu
target_compiler.host = x86_64-poky-linux-gnu

Moreover, if I bypass the assertion check and then build, why do the compiler asks to switch to nightly channel instead of continuing to stable? I am wondering how does it gets the Z option during the build since I did not not provide any such options.

test [mir-opt] tests/mir-opt/reference_prop.rs ... ok
test [mir-opt] tests/mir-opt/inline/polymorphic_recursion.rs ... ok
test result: ok. 249 passed; 0 failed; 13 ignored; 0 measured; 0 filtered out; finished in 1.39s

error: the option `Z` is only accepted on the nightly compiler
note: selecting a toolchain with `+toolchain` arguments require a rustup proxy; see <https://rust-lang.github.io/rustup/concepts/index.html>
help: consider switching to a nightly toolchain: `rustup default nightly`
note: for more information about Rust's stability policy, see <https://doc.rust-lang.org/book/appendix-07-nightly-rust.html#unstable-features>
thread 'main' panicked at 'failed to gather the target spec for i686-unknown-linux-gnu', synthetic_targets.rs:66:9
Build completed unsuccessfully in 0:05:27

Let me know if I am missing something

[onur-ozkan]

Do you have a custom config.toml?

[Yashinde145]

The config.toml generated during the rust build is as follows-

build_dir is the directory where I am building rust (using cmd bitbake rust in yocto poky sources)

[target.x86_64-poky-linux-gnu]                                                                                                                                                                                  
llvm-config = "build_dir/recipe-sysroot/usr/lib/llvm-rust/bin/llvm-config"                                                                         
cxx = "build_dir/wrapper/target-rust-cxx"                                                                                                          
cc = "build_dir/wrapper/target-rust-cc"                                                                                                            
linker = "build_dir/wrapper/target-rust-ccld"                                                                                                      
                                                                                                                                                                                                                
[target.x86_64-unknown-linux-gnu]                                                                                                                                                                               
llvm-config = "build_dir/recipe-sysroot-native/usr/lib/llvm-rust/bin/llvm-config"                                                                  
cxx = "build_dir/wrapper/build-rust-cxx"                                                                                                           
cc = "build_dir/wrapper/build-rust-cc"                                                                                                             
linker = "build_dir/wrapper/build-rust-ccld"                                                                                                       
                                                                                                                                                                                                                
[llvm]                                                                                                                                                                                                          
static-libstdcpp = false                                                                                                                                                                                        
                                                                                                                                                                                                                
[rust]                                                                                                                                                                                                          
rpath = true                                                                                                                                                                                                    
channel = "stable"                                                                                                                                                                                              
optimize = true                                                                                                                                                                                                 
verbose-tests = true                                                                                                                                                                                            
                                                                                                                                                                                                                
[build]                                                                                                                                                                                                         
submodules = false                                                                                                                                                                                              
docs = false                                                                                                                                                                                                    
rustc = "build_dir/rust-snapshot/bin/rustc"                                                                                                        
profiler = true                                                                                                                                                                                                 
cargo = "build_dir/rust-snapshot/bin/cargo"                                                                                                        
vendor = true                                                                                                                                                                                                   
target = ["x86_64-poky-linux-gnu"]                                                                                                                                                                              
host = ["x86_64-poky-linux-gnu"]                                                                                                                                                                                
build = "x86_64-unknown-linux-gnu"                                                                                                                                                                              
                                                                                                                                                                                                                
[install]                                                                                                                                                                                                       
prefix = "build_dir/image/usr"                                                                                                                     
bindir = "build_dir/image/usr/bin"                                                                                                                 
libdir = "build_dir/image/usr/lib"                                                                                                                 
datadir = "build_dir/image/usr/share"                                                                                                              
mandir = "build_dir/image/usr/share/man"

[onur-ozkan]

iirc bitbake rust will give you the stable 1.68 compiler. If so, please remove build.cargo and build.rust from your configuration, and use the beta compiler which will be downloaded from CI automatically during the bootstrapping.