Starlark alloc alignment assertions fail following rustc 1.72 TypeId changes

[cormacrelf]

Latest builds are red, bisecting reveals 21381685c as the source. Weirdly only macos seems to be affected.

See rust-lang/rust#109953, which I am pretty sure this is related to. The alloc is now aligned to 16 bytes with no code changes. Compare the changelog https://releases.rs/docs/1.72.0/

I should mention this seems to happen when you run any command that evaluates starlark.

Backtrace showing the assertion failure

nightly-2023-06-27 thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
stack backtrace:
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::IsAnyOfTwo<starlark::values::typing::type_compiled::matchers::IsNone, starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
thread 'buck2-rt' panicked at 'Unexpected alignment in Starlark arena. Type starlark::values::layout::avalue::AValueImpl<starlark::values::layout::avalue::Simple, starlark::values::typing::type_compiled::compiled::TypeCompiledImplAsStarlarkValue<starlark::values::typing::type_compiled::matchers::StarlarkTypeIdMatcher>> has alignment 16, expected <= 8', starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
   0: rust_begin_unwind
             at /rustc/36fb58e433c782e27dd41034284e157cf86d587f/library/std/src/panicking.rs:593:5
   1: core::panicking::panic_fmt
             at /rustc/36fb58e433c782e27dd41034284e157cf86d587f/library/core/src/panicking.rs:67:14
   2: starlark::values::layout::heap::arena::Arena<A>::alloc_uninit
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/layout/heap/arena.rs:174:9
   3: starlark::values::layout::heap::arena::Arena<A>::alloc
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/layout/heap/arena.rs:249:26
   4: starlark::values::layout::heap::heap_type::Heap::alloc_raw
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/layout/heap/heap_type.rs:592:33
   5: starlark::values::layout::heap::heap_type::Heap::alloc_simple
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/layout/heap/heap_type.rs:761:9
   6: starlark::values::typing::type_compiled::compiled::TypeCompiled<starlark::values::layout::value::Value>::alloc
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/typing/type_compiled/compiled.rs:378:22
   7: <starlark::values::typing::type_compiled::factory::TypeCompiledFactory as starlark::values::typing::type_compiled::alloc::TypeMatcherAlloc>::alloc
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/typing/type_compiled/factory.rs:47:9
   8: starlark::values::typing::type_compiled::compiled::TypeCompiled<starlark::values::layout::value::Value>::from_ty
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/typing/type_compiled/compiled.rs:435:9
   9: starlark::values::typing::type_compiled::compiled::TypeCompiled<starlark::values::layout::value::Value>::new
             at /Users/me/src/buck2/starlark-rust/starlark/src/values/typing/type_compiled/compiled.rs:455:16
  10: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::alloc_value_for_type
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:102:18
  11: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::eval_path_as_type
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:151:9
  12: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::eval_expr_as_type
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:159:50
  13: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::populate_types_in_type_expr
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:245:26
  14: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::populate_types_in_stmt::{{closure}}
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:254:55
  15: starlark_syntax::syntax::uniplate::<impl starlark_syntax::syntax::ast::StmtP<P>>::visit_type_expr_err_mut
             at /Users/me/src/buck2/starlark-rust/starlark_syntax/src/syntax/uniplate.rs:287:25
  16: starlark::eval::compiler::types::<impl starlark::eval::compiler::Compiler>::populate_types_in_stmt
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/types.rs:254:9
  17: starlark::eval::compiler::module::<impl starlark::eval::compiler::Compiler>::eval_top_level_stmt
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/module.rs:150:13
  18: starlark::eval::compiler::module::<impl starlark::eval::compiler::Compiler>::eval_module
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/compiler/module.rs:219:21
  19: starlark::eval::<impl starlark::eval::runtime::evaluator::Evaluator>::eval_module
             at /Users/me/src/buck2/starlark-rust/starlark/src/eval/mod.rs:136:19
  20: buck2_interpreter_for_build::interpreter::interpreter_for_cell::InterpreterForCell::eval
             at /Users/me/src/buck2/app/buck2_interpreter_for_build/src/interpreter/interpreter_for_cell.rs:469:19
  21: buck2_interpreter_for_build::interpreter::interpreter_for_cell::InterpreterForCell::eval_module
             at /Users/me/src/buck2/app/buck2_interpreter_for_build/src/interpreter/interpreter_for_cell.rs:510:9
  22: buck2_interpreter_for_build::interpreter::dice_calculation_delegate::DiceCalculationDelegate::eval_module_uncached::{{closure}}::{{closure}}
             at /Users/me/src/buck2/app/buck2_interpreter_for_build/src/interpreter/dice_calculation_delegate.rs:271:34
  23: buck2_interpreter::dice::starlark_provider::with_starlark_eval_provider::{{closure}}
             at /Users/me/src/buck2/app/buck2_interpreter/src/dice/starlark_provider.rs:96:13
  24: buck2_interpreter_for_build::interpreter::dice_calculation_delegate::DiceCalculationDelegate::eval_module_uncached::{{closure}}
             at /Users/me/src/buck2/app/buck2_interpreter_for_build/src/interpreter/dice_calculation_delegate.rs:292:10
  25: buck2_interpreter_for_build::interpreter::dice_calculation_delegate::DiceCalculationDelegate::eval_module::{{closure}}::<impl dice::api::key::Key for buck2_interpreter_for_build::interpreter::dice_calculation_delegate::keys::EvalImportKey>::compute::{{closure}}
             at /Users/me/src/buck2/app/buck2_interpreter_for_build/src/interpreter/dice_calculation_delegate.rs:175:22
  26: dice::legacy::<impl dice::legacy::incremental::evaluator::Evaluator for dice::legacy::key::StoragePropertiesForKey<K>>::eval::{{closure}}
             at /Users/me/src/buck2/dice/dice/src/legacy/mod.rs:280:14
  27: dice::legacy::incremental::IncrementalEngine<K>::compute::{{closure}}::{{closure}}
             at /Users/me/src/buck2/dice/dice/src/legacy/incremental/mod.rs:579:14
  28: dice::legacy::incremental::IncrementalEngine<K>::compute::{{closure}}
             at /Users/me/src/buck2/dice/dice/src/legacy/incremental/mod.rs:542:5
  29: dice::legacy::incremental::IncrementalEngine<K>::new_dice_task::{{closure}}
             at /Users/me/src/buck2/dice/dice/src/legacy/incremental/mod.rs:488:26
  30: more_futures::cancellable_future::CancellableFutureProj<F>::poll_inner
             at /Users/me/src/buck2/shed/more_futures/src/cancellable_future.rs:257:13
  31: <more_futures::cancellable_future::CancellableFuture<F> as core::future::future::Future>::poll
             at /Users/me/src/buck2/shed/more_futures/src/cancellable_future.rs:300:20
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
Build ID: 8ee76dad-1ad3-440b-8327-fbd8d471fc36
Jobs completed: 143. Time elapsed: 0.3s.
Command failed: Buck daemon event bus encountered an error, the root cause (if available) is displayed above this message.

Caused by:
    0: status: Unknown, message: "h2 protocol error: error reading a body from connection: stream closed because of a broken pipe", details: [], metadata: MetadataMap { headers: {} }
    1: error reading a body from connection: stream closed because of a broken pipe
    2: stream closed because of a broken pipe

[ndmitchell]

Thanks for the report! We'll take a look. Kind of surprised our internal CI didn't bleat loudly at this,

[stepancheg]

Edit: nevermind, I can reproduce it.

[stepancheg]

Kind of surprised our internal CI didn't bleat loudly at this

u128 is has alignment 8 on x86_64, but 16 on Apple Silicon.

[stepancheg]

Internal: should be fixed in D49019964.