nightly cross build started failing 2025-08-16

[jeremyd2019]

Summary

I have a GitHub Actions workflow that cross-builds a nightly rust toolchain from x86_64-pc-windows-gnu to x86_64-pc-cygwin. On 2025-08-16, this started failing.

Command used

  PKG_CONFIG_SYSROOT_DIR="$(cygpath -w /)" \
  PKG_CONFIG="$(cygpath -w /usr/bin/pkgconf.exe)" \
  LIBGIT2_NO_VENDOR=1 \
  OPENSSL_DIR="$(cygpath -w /usr)" \
  OPENSSL_LIB_DIR="$(cygpath -w /usr/lib)" \
  OPENSSL_STATIC=0 \
  DESTDIR="$(cygpath -w "$PWD/build-Cygwin/dest-rust")" \
  python x.py install --stage 2

Expected behaviour

successful build, as on 2025-08-15 and before

Actual behaviour

Uplifting rustc (stage2 -> stage3)
ERROR: Unable to find the stamp file D:\cygwin\home\runneradmin\rustc-nightly-src\build-Cygwin\x86_64-pc-cygwin\stage3-rustc\x86_64-pc-cygwin\release\.librustc-stamp, did you try to keep a nonexistent build stage?
Build completed unsuccessfully in 1:21:24

Bootstrap configuration (bootstrap.toml)

# see src/bootstrap/defaults/
profile = "dist"

# see src/bootstrap/src/utils/change_tracker.rs
change-id = 138986

[build]
submodules = false
build = "x86_64-pc-windows-gnu"
host = ["x86_64-pc-cygwin"]
target = [
  "x86_64-pc-cygwin",
]
build-dir = "build-Cygwin"
python = "$MSYS2_ROOT/mingw64/bin/python.exe"
locked-deps = true
vendor = true
tools = [
"clippy", "rustdoc", "rustfmt", "rust-analyzer-proc-macro-srv", "analysis",
  "cargo",
]
profiler = true
docs = false

[install]
prefix = "/usr"
sysconfdir = "/etc"

[llvm]
link-shared = true

[rust]
codegen-units-std = 1
channel = "stable"
rpath = false
frame-pointers = true
llvm-bitcode-linker = false
lld = false
llvm-tools = false
codegen-tests = false
deny-warnings = false
backtrace-on-ice = true
control-flow-guard = true
lto = "thin"

[dist]
compression-formats = ["gz"]
compression-profile = "fast"
include-mingw-linker = false

[target.x86_64-pc-windows-gnu]
cc = "$MSYS2_ROOT/mingw64/bin/clang.exe"
cxx = "$MSYS2_ROOT/mingw64/bin/clang++.exe"
ar = "$MSYS2_ROOT/mingw64/bin/llvm-ar.exe"
ranlib = "$MSYS2_ROOT/mingw64/bin/llvm-ranlib.exe"
linker = "$MSYS2_ROOT/mingw64/bin/clang.exe"
llvm-config = "$MSYS2_ROOT/mingw64/bin/llvm-config.exe"
crt-static = true

[target.x86_64-pc-cygwin]
cc = "$WORKSPACE/gcc.exe"
cxx = "$WORKSPACE/g++.exe"
ar = "$WORKSPACE/ar.exe"
ranlib = "$WORKSPACE/ranlib.exe"
linker = "$WORKSPACE/x86_64-pc-cygwin-gcc.exe"
llvm-config = "$WORKSPACE/llvm-config.exe"
profiler = false

Operating system

windows-latest

HEAD

https://static.rust-lang.org/dist/2025-08-16/rustc-nightly-src.tar.xz

Additional context

https://github.com/jeremyd2019/cygwin-rust-bootstrap/actions/runs/17007568309/job/48225722817 - all the scripts and configs are in that repository.

Build Log

too long to paste, see https://github.com/jeremyd2019/cygwin-rust-bootstrap/actions/runs/17007568309/job/48225722817

[Kobzol]

This was most likely caused by #145310, thanks for the report. I'll take a look.

[Kobzol]

Can you please check (starting with tomorrow's nightly) that the issue was indeed fixed? Thanks!