`Option::unwrap()` on a `None` value panic on stable-aarch64-pc-windows-msvc

[jqnatividad]

The same code compiles on other platforms.

https://github.com/dathere/qsv/actions/runs/19927389915/job/57130497725#step:7:2033

   Compiling assert-json-diff v2.0.2
     Running `C:\Users\runneradmin\.rustup\toolchains\stable-aarch64-pc-windows-msvc\bin\rustc.exe --crate-name assert_json_diff --edition=2018 C:\Users\runneradmin\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\assert-json-diff-2.0.2\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --check-cfg cfg(docsrs,test) --check-cfg "cfg(feature, values())" -C metadata=4bf26ffa7290fbf2 -C extra-filename=-30e6d087910fc91a --out-dir C:\a\qsv\qsv\target\debug\deps -L dependency=C:\a\qsv\qsv\target\debug\deps --extern serde=C:\a\qsv\qsv\target\debug\deps\libserde-11c4952445fbfc70.rmeta --extern serde_json=C:\a\qsv\qsv\target\debug\deps\libserde_json-156aa054cb642c11.rmeta --cap-lints allow`

thread 'rustc' (8836) panicked at /rust/deps\ar_archive_writer-0.5.1\src\archive_writer.rs:496:14:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0:     0x7ffce45cbff0 - std::backtrace_rs::backtrace::win64::trace
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\..\..\backtrace\src\backtrace\win64.rs:85
   1:     0x7ffce45cbff0 - std::backtrace_rs::backtrace::trace_unsynchronized
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66
   2:     0x7ffce45cbff0 - std::sys::backtrace::_print_fmt
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\sys\backtrace.rs:66
   3:     0x7ffce45cbff0 - std::sys::backtrace::impl$0::print::impl$0::fmt
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\sys\backtrace.rs:39
   4:     0x7ffce45e0378 - core::fmt::rt::Argument::fmt
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\core\src\fmt\rt.rs:173
   5:     0x7ffce45e0378 - core::fmt::write
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\core\src\fmt\mod.rs:1468
   6:     0x7ffce4598b6c - std::io::default_write_fmt
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\io\mod.rs:639
   7:     0x7ffce4598b6c - std::io::Write::write_fmt<std::sys::stdio::windows::Stderr>
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\io\mod.rs:1954
   8:     0x7ffce45af160 - std::sys::backtrace::BacktraceLock::print
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\sys\backtrace.rs:42
   9:     0x7ffce45b5c1c - std::panicking::default_hook::closure$0
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\panicking.rs:301
  10:     0x7ffce45b5a68 - std::panicking::default_hook
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\panicking.rs:328
  11:     0x7ffcdec13e64 - <&mut serde_json[d617299a821b15f3]::ser::Serializer<&mut alloc[cfd67d73170bd3b5]::vec::Vec<u8>, serde_json[d617299a821b15f3]::ser::PrettyFormatter> as serde[b3103cb712ebc94e]::ser::Serializer>::collect_seq::<&alloc[cfd67d73170bd3b5]::vec::Vec<serde_json[d617299a821b15f3]::value::Value>>
  12:     0x7ffce45b6514 - std::panicking::panic_with_hook
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\panicking.rs:842
  13:     0x7ffce45b6228 - std::panicking::panic_handler::closure$0
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\panicking.rs:700
  14:     0x7ffce45af340 - std::sys::backtrace::__rust_end_short_backtrace<std::panicking::panic_handler::closure_env$0,never$>
                               at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library\std\src\sys\backtrace.rs:174

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.91.1 (ed61e7d7e 2025-11-07) running on aarch64-pc-windows-msvc

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack
error: could not compile `polars-ops` (lib)

Caused by:
  process didn't exit successfully: `C:\Users\runneradmin\.rustup\toolchains\stable-aarch64-pc-windows-msvc\bin\rustc.exe --crate-name polars_ops --edition=2024 C:\Users\runneradmin\.cargo\git\checkouts\polars-54176cdfb679e240\8035d57\crates\polars-ops\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --allow=clippy::collapsible_if --cfg "feature=\"abs\"" --cfg "feature=\"asof_join\"" --cfg "feature=\"base64\"" --cfg "feature=\"binary_encoding\"" --cfg "feature=\"business\"" --cfg "feature=\"chrono\"" --cfg "feature=\"chrono-tz\"" --cfg "feature=\"chunked_ids\"" --cfg "feature=\"cov\"" --cfg "feature=\"cross_join\"" --cfg "feature=\"cum_agg\"" --cfg "feature=\"dtype-array\"" --cfg "feature=\"dtype-categorical\"" --cfg "feature=\"dtype-date\"" --cfg "feature=\"dtype-datetime\"" --cfg "feature=\"dtype-decimal\"" --cfg "feature=\"dtype-duration\"" --cfg "feature=\"dtype-f16\"" --cfg "feature=\"dtype-i128\"" --cfg "feature=\"dtype-i16\"" --cfg "feature=\"dtype-i8\"" --cfg "feature=\"dtype-struct\"" --cfg "feature=\"dtype-time\"" --cfg "feature=\"dtype-u128\"" --cfg "feature=\"dtype-u16\"" --cfg "feature=\"dtype-u8\"" --cfg "feature=\"extract_jsonpath\"" --cfg "feature=\"fused\"" --cfg "feature=\"hex\"" --cfg "feature=\"iejoin\"" --cfg "feature=\"is_in\"" --cfg "feature=\"jsonpath_lib\"" --cfg "feature=\"log\"" --cfg "feature=\"object\"" --cfg "feature=\"peaks\"" --cfg "feature=\"performant\"" --cfg "feature=\"pivot\"" --cfg "feature=\"polars-json\"" --cfg "feature=\"rand\"" --cfg "feature=\"rank\"" --cfg "feature=\"rle\"" --cfg "feature=\"round_series\"" --cfg "feature=\"search_sorted\"" --cfg "feature=\"semi_anti_join\"" --cfg "feature=\"serde\"" --cfg "feature=\"serde_json\"" --cfg "feature=\"string_normalize\"" --cfg "feature=\"string_reverse\"" --cfg "feature=\"strings\"" --cfg "feature=\"timezones\"" --cfg "feature=\"unicode-normalization\"" --cfg "feature=\"unicode-reverse\"" --cfg "feature=\"unique_counts\"" --check-cfg cfg(docsrs,test) --check-cfg "cfg(feature, values(\"abs\", \"aho-corasick\", \"allow_unused\", \"approx_unique\", \"array_any_all\", \"array_count\", \"array_to_struct\", \"asof_join\", \"base64\", \"big_idx\", \"binary_encoding\", \"bitwise\", \"business\", \"chrono\", \"chrono-tz\", \"chunked_ids\", \"cov\", \"cross_join\", \"cum_agg\", \"cutqcut\", \"diff\", \"dsl-schema\", \"dtype-array\", \"dtype-categorical\", \"dtype-date\", \"dtype-datetime\", \"dtype-decimal\", \"dtype-duration\", \"dtype-extension\", \"dtype-f16\", \"dtype-i128\", \"dtype-i16\", \"dtype-i8\", \"dtype-struct\", \"dtype-time\", \"dtype-u128\", \"dtype-u16\", \"dtype-u8\", \"ewma\", \"ewma_by\", \"extract_groups\", \"extract_jsonpath\", \"find_many\", \"fused\", \"gather\", \"hash\", \"hex\", \"hist\", \"iejoin\", \"index_of\", \"interpolate\", \"interpolate_by\", \"is_between\", \"is_close\", \"is_first_distinct\", \"is_in\", \"is_last_distinct\", \"is_unique\", \"jsonpath_lib\", \"list_any_all\", \"list_count\", \"list_drop_nulls\", \"list_filter\", \"list_gather\", \"list_sample\", \"list_sets\", \"list_to_struct\", \"log\", \"merge_sorted\", \"mode\", \"moment\", \"nightly\", \"object\", \"pct_change\", \"peaks\", \"performant\", \"pivot\", \"polars-json\", \"propagate_nans\", \"rand\", \"rand_distr\", \"random\", \"rank\", \"reinterpret\", \"repeat_by\", \"replace\", \"rle\", \"rolling_window\", \"rolling_window_by\", \"round_series\", \"search_sorted\", \"semi_anti_join\", \"serde\", \"serde_json\", \"simd\", \"string_encoding\", \"string_normalize\", \"string_pad\", \"string_reverse\", \"string_to_integer\", \"strings\", \"timezones\", \"to_dummies\", \"top_k\", \"unicode-normalization\", \"unicode-reverse\", \"unique_counts\"))" -C metadata=d19176ad8616a1bd -C extra-filename=-e5cc54971498c135 --out-dir C:\a\qsv\qsv\target\debug\deps -L dependency=C:\a\qsv\qsv\target\debug\deps --extern argminmax=C:\a\qsv\qsv\target\debug\deps\libargminmax-cdafc56eb0f0943e.rmeta --extern base64=C:\a\qsv\qsv\target\debug\deps\libbase64-33d5cb144ca4c058.rmeta --extern bytemuck=C:\a\qsv\qsv\target\debug\deps\libbytemuck-9fc342f5d4e8d48e.rmeta --extern chrono=C:\a\qsv\qsv\target\debug\deps\libchrono-93428fb7cde54bee.rmeta --extern chrono_tz=C:\a\qsv\qsv\target\debug\deps\libchrono_tz-e08cb1062db49cae.rmeta --extern either=C:\a\qsv\qsv\target\debug\deps\libeither-de9ceffdcc89e80d.rmeta --extern hashbrown=C:\a\qsv\qsv\target\debug\deps\libhashbrown-5ae7e8fc9bdc9da8.rmeta --extern hex=C:\a\qsv\qsv\target\debug\deps\libhex-dbee9d2517f13886.rmeta --extern indexmap=C:\a\qsv\qsv\target\debug\deps\libindexmap-7095c987ab845e8d.rmeta --extern jsonpath_lib=C:\a\qsv\qsv\target\debug\deps\libjsonpath_lib-22b103ce9753e904.rlib --extern libm=C:\a\qsv\qsv\target\debug\deps\liblibm-b15c5c33931d2112.rmeta --extern memchr=C:\a\qsv\qsv\target\debug\deps\libmemchr-febf7e1e8febaa1f.rmeta --extern num_traits=C:\a\qsv\qsv\target\debug\deps\libnum_traits-c950a19d84ae4098.rmeta --extern arrow=C:\a\qsv\qsv\target\debug\deps\libpolars_arrow-e7fbf89601e1b9f9.rmeta --extern polars_compute=C:\a\qsv\qsv\target\debug\deps\libpolars_compute-c3985f51053b983d.rmeta --extern polars_core=C:\a\qsv\qsv\target\debug\deps\libpolars_core-2ab26c3eec42ac10.rmeta --extern polars_error=C:\a\qsv\qsv\target\debug\deps\libpolars_error-bc491533024df6ae.rmeta --extern polars_json=C:\a\qsv\qsv\target\debug\deps\libpolars_json-ce475413307aa4b9.rmeta --extern polars_schema=C:\a\qsv\qsv\target\debug\deps\libpolars_schema-642913396038620b.rmeta --extern polars_utils=C:\a\qsv\qsv\target\debug\deps\libpolars_utils-fbc2c8aecad545f3.rmeta --extern rand=C:\a\qsv\qsv\target\debug\deps\librand-01011ed50f1c0abe.rmeta --extern rayon=C:\a\qsv\qsv\target\debug\deps\librayon-634638a905bccac4.rmeta --extern regex=C:\a\qsv\qsv\target\debug\deps\libregex-d759ac90cf9ec05c.rmeta --extern regex_syntax=C:\a\qsv\qsv\target\debug\deps\libregex_syntax-aff8f353c935fe2f.rmeta --extern serde=C:\a\qsv\qsv\target\debug\deps\libserde-11c4952445fbfc70.rmeta --extern serde_json=C:\a\qsv\qsv\target\debug\deps\libserde_json-156aa054cb642c11.rmeta --extern strum_macros=C:\a\qsv\qsv\target\debug\deps\strum_macros-fed1b8bf323b2f6f.dll --extern unicode_normalization=C:\a\qsv\qsv\target\debug\deps\libunicode_normalization-353d5d1d6e9c9833.rmeta --extern unicode_reverse=C:\a\qsv\qsv\target\debug\deps\libunicode_reverse-7f86b0099b59ff0a.rmeta --cap-lints allow -L native=C:\a\qsv\qsv\target\debug\build\lz4-sys-2bb4e695ef03e832\out -L native=C:\a\qsv\qsv\target\debug\build\zstd-sys-5b2acdec4c729e7a\out -L native=C:\a\qsv\qsv\target\debug\build\ring-c336c0cb09753de0\out -L native=C:\a\qsv\qsv\target\debug\build\stacker-ceec06590ceac86b\out -L native=C:\a\qsv\qsv\target\debug\build\psm-c0bfbb85036cf1e3\out -L "native=C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\atlmfc\lib\arm64" -L native=C:\Users\runneradmin\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\windows_aarch64_msvc-0.53.1\lib -L "native=C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\atlmfc\lib\arm64" -L native=C:\Users\runneradmin\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\windows_aarch64_msvc-0.52.6\lib -L "native=C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\atlmfc\lib\arm64" -L "native=C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.44.35207\atlmfc\lib\arm64"` (exit code: 101)
Error: Process completed with exit code 1.

[bjorn3]

Is it possible that the rlib would end up larger than 4GB? The symbol table of ar archives on Windows always uses 32bit pointers. This is unlike other platforms where it uses 64bit pointers when compiling for a 64bit architecture.

[jqnatividad]

I managed to get my project compiling again on Windows ARM after I disabled a feature that brought in the polars dependency.

Will report the issue to polars and report back.

[orlp]

I don't really see how this is actionable for us as Polars, the panic is in the Rust compiler.

[orlp]

@bjorn3

Is it possible that the rlib would end up larger than 4GB?

Yes, it could be.

@jqnatividad Does the problem go away if you build without debug symbols?

[bjorn3]

I don't think this is a bug in either Polars or ar_archive_writer. AFAICT there is a fundamental limitation in the COFF ar archive format variant for files larger than 4GB. You simply cannot have the symbol table reference a file after the 4GB mark. LLVM truncates the pointer, which produces a corrupt archive. ar_archive_writer on the other hand loudly complains about the overflow.

https://github.com/llvm/llvm-project/blob/113f058d73ec9850cdeb476c987971ca02a57350/llvm/lib/Object/ArchiveWriter.cpp#L652-L658

While in the past the gnu ar archive format variant was used on Windows, we had to switch to the coff variant due to this being necessary for arm64ec: rust-lang/rust#123467

Edit: Github didn't show your last commit when I commented this.

[tgross35]

At a minimum, the panic should probably provide a helpful error message.

@dpaoliello do you happen to know if anything has changed with how LLVM does symbol tables for arm64ec, such that we might be able to switch back to the other format?

[dpaoliello]

I honestly don't know: we might be able to use GNU for non-Arm64EC, but I don't know off the top of my head what else that would affect.

[jqnatividad]

@bjorn3

Is it possible that the rlib would end up larger than 4GB?

Yes, it could be.

@jqnatividad Does the problem go away if you build without debug symbols?

I'm happy to report that I was able to compile on Windows ARM when I removed debug symbols.

dathere/qsv@d22a817

https://github.com/dathere/qsv/actions/runs/19972668252

[orlp]

I think that most likely confirms the 4GB issue then. I'm not sure what the way forward is, Polars is definitely one of the larger packages but it certainly won't be unique in hitting this limit...

[tgross35]

I think three things to do here are:

1. Make this failure nicer by returning an io::Error with a useful message, or at least panicking with something other than plain .unwrap()
2. Open an issue in rust-lang/rust about investigating whether we might be able to change formats
3. If there isn't already an LLVM issue for how it generates EC symbol tables (leading to MSVC targets should use COFF as their archive format rust#123467), then open one

I think we definitely need to transfer off of the COFF format (by 2038 at the latest given it has that issue). But if that is going to take a while, the only option is to really twiddle flags to get binary size under the effective limit. Or somehow split the binary, though that sounds pretty painful.