python3-sys build error on

[Peter-Noble]

Hey, we're trying to build rust-cpython on windows and running into the following error:

C:\Users\johnr\Documents\CrowdMaster\rust\channel_world>cargo build Compiling utf8-ranges v0.1.3 Compiling winapi-build v0.1.1 Compiling winapi v0.2.8 Compiling cpython v0.1.0 (https://github.com/dgrunwald/rust-cpython.git#5395cd41) Compiling regex-syntax v0.3.9 Compiling memchr v0.1.11 Compiling kernel32-sys v0.2.2 Compiling aho-corasick v0.5.3 Compiling thread-id v2.0.0 Compiling thread_local v0.2.7 Compiling regex v0.1.80 Compiling python3-sys v0.1.3 (https://github.com/dgrunwald/rust-cpython.git#5395cd41) error: failed to run custom build command for python3-sys v0.1.3 (https://github.com/dgrunwald/rust-cpython.git#5395cd41)`
process didn't exit successfully: C:\Users\johnr\Documents\CrowdMaster\rust\target\debug\build\python3-sys-26c0bb845f0b7d10\b uild-script-build (exit code: 101)
--- stderr
thread 'main' panicked at 'called Result::unwrap() on an Err value: "failed to run python interpreter \"python3\" \"-c\" \"import sys; import sysconfig; print(sys.version_info[0:2]); print(sysconfig.get_config_var(\\\'LIBDIR\\\')); print(sysconfig .get_config_var(\\\'Py_ENABLE_SHARED\\\')); print(sysconfig.get_config_var(\\\'LDVERSION\\\') or \\\'%s%s\\\' % (sysconfig.get _config_var(\\\'py_version_short\\\'), sysconfig.get_config_var(\\\'DEBUG_EXT\\\') or \\\'\\\')); print(sys.exec_prefix);\":
The system cannot find the file specified. (os error 2)"', src\libcore\result.rs:860
note: Run with RUST_BACKTRACE=1 for a backtrace.`

Cargo.toml looks like this:
`[package]
name = "channel_world"
version = "0.1.0"
authors = ["Peter-Noble peter@noblesque.org.uk"]

[lib]
name = "channel_world"
crate-type = ["cdylib"]

[dependencies.cpython]
version = "0.1.0"
default-features = false
features = ["python3-sys"]
git = "https://github.com/dgrunwald/rust-cpython.git"`

The same project builds correctly on Linux. Any help would be greatly appreciated.

[ssokolow]

"failed to run python interpreter \"python3\" \"-c\" \"import sys; import sysconfig; print(sys.version_info[0:2]); print(sysconfig.get_config_var(\\\'LIBDIR\\\')); print(sysconfig .get_config_var(\\\'Py_ENABLE_SHARED\\\')); print(sysconfig.get_config_var(\\\'LDVERSION\\\') or \\\'%s%s\\\' % (sysconfig.get _config_var(\\\'py_version_short\\\'), sysconfig.get_config_var(\\\'DEBUG_EXT\\\') or \\\'\\\')); print(sys.exec_prefix);\":
The system cannot find the file specified. (os error 2)"

My first suspicion is that there's no python3.exe in the PATH on your machine.

What happens if you type python3 in a cmd.exe window?

[Peter-Noble]

python3 works on cmd. It wasn't adding python3 to the path from the python installer (possibly because the executable is called python.exe rather than python3.exe?) so we had to add a file called python3.cmd to a directory in PATH which contains:
<path to python 3 executable> %*

[ssokolow]

That's probably the source of your problem.

It's probably using Rust's Command::spawn, and, on Windows, that uses the CreateProcess API. The only thing it'll look for when given python3 is python3.exe.

(As I understand it, the behaviour you see in cmd.exe is provided by a higher-level API called ShellExecuteEx.)

Try making a copy of python.exe and naming it python3.exe to see if that works around the problem.

[Peter-Noble]

Hey, sorry for the delay replying. Duplicating python.exe and renaming worked perfectly. Thanks for your help!

[zorbanaut]

python3.exe is not provided by python installer.
For me, prepending C:\Python36 to PATH has helped.

[theoctober19th]

I'm on macOS 13.2.1 (arm64) and just aliasing python to python3 worked for me.