\n in path causing issues on windows

[nobsclement]

Bug Description

When building a brand new project created with maturin new, I see that error: failed to parse PyO3 config: Error { value: "expected key=value pair on line 7", source: None }.

After some investigations, I found out that from_cargo_dep_env() replaces every \\n with \n.

pyo3/pyo3-build-config/src/impl_.rs

Line 369 in cb48557

.map(|buf| InterpreterConfig::from_reader(buf.replace("\\n", "\n").as_bytes()))

Here is what buf.as_str() looks like before that replace is done:

"implementation=CPython\\nversion=3.9\\nshared=true\\nabi3=false\\nlib_name=python39\\nlib_dir=C:\\Users\\nobsclement\\AppData\\Local\\Programs\\Python\\Python39\\libs\\nexecutable=D:\\code\\nobody\\rust\\libs\\test_package\\.venv\\Scripts\\python.exe\\npointer_width=64\\nbuild_flags=\\nsuppress_build_script_link_lines=false\\n"

And after the replace:

"implementation=CPython\nversion=3.9\nshared=true\nabi3=false\nlib_name=python39\nlib_dir=C:\\Users\nobsclement\\AppData\\Local\\Programs\\Python\\Python39\\libs\nexecutable=D:\\code\nobody\\rust\\libs\\test_package\\.venv\\Scripts\\python.exe\npointer_width=64\nbuild_flags=\nsuppress_build_script_link_lines=false\n"

Note that lib_dir and executable now have wrong paths: C:\\Users\nobsclement\\AppData\\Local\\Programs\\Python\\Python39\\libs and D:\\code\nobody\\rust\\libs\\test_package\\.venv\\Scripts\\python.exe.

The bug occurs when the parse_value macro trims the line and interprets the path as two (or more) lines:

pyo3/pyo3-build-config/src/impl_.rs

Line 379 in cb48557

$variable = Some($value.trim().parse().context(format!(

Steps to Reproduce

On windows:

1. Source a venv in a path that contains a folder that starts with a lowercase n
2. Use maturin build

The build crashed when parsing lib_dir, but it should also crash when parsing executable which those steps should reproduce.

Backtrace

error: failed to run custom build command for `pyo3 v0.16.3`

Caused by:
  process didn't exit successfully: `D:\code\nobody\rust\target\debug\build\pyo3-b6ef0b8efd5a0d05\build-script-build` (exit code: 101)
  --- stderr
  thread 'main' panicked at 'failed to parse PyO3 config: Error { value: "expected key=value pair on line 7", source: None }', C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\pyo3-build-config-0.16.3\src\lib.rs:94:10
  stack backtrace:
     0: std::panicking::begin_panic_handler
               at /rustc/7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c\/library\std\src\panicking.rs:584
     1: core::panicking::panic_fmt
               at /rustc/7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c\/library\core\src\panicking.rs:143
     2: core::result::unwrap_failed
               at /rustc/7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c\/library\core\src\result.rs:1749
     3: enum$<core::result::Result<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::errors::Error> >::expect<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::errors::Error>
               at /rustc/7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c\library\core\src\result.rs:1022
     4: pyo3_build_config::get::closure$0
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\pyo3-build-config-0.16.3\src\lib.rs:83
     5: once_cell::sync::impl$6::get_or_init::closure$0<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::get::closure_env$0>
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\lib.rs:974
     6: once_cell::imp::impl$4::initialize::closure$0<pyo3_build_config::impl_::InterpreterConfig,once_cell::sync::impl$6::get_or_init::closure_env$0<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::get::closure_env$0>,enum$<once_cell::sync::impl$6:
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\imp_std.rs:95
     7: once_cell::imp::initialize_inner
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\imp_std.rs:171
     8: once_cell::imp::OnceCell<pyo3_build_config::impl_::InterpreterConfig>::initialize<pyo3_build_config::impl_::InterpreterConfig,once_cell::sync::impl$6::get_or_init::closure_env$0<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::get::closure_e
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\imp_std.rs:93
     9: once_cell::sync::OnceCell<pyo3_build_config::impl_::InterpreterConfig>::get_or_try_init<pyo3_build_config::impl_::InterpreterConfig,once_cell::sync::impl$6::get_or_init::closure_env$0<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::get::clo
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\lib.rs:1014
    10: once_cell::sync::OnceCell<pyo3_build_config::impl_::InterpreterConfig>::get_or_init<pyo3_build_config::impl_::InterpreterConfig,pyo3_build_config::get::closure_env$0>
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\once_cell-1.10.0\src\lib.rs:974
    11: pyo3_build_config::get
               at C:\Users\nobsclement\.cargo\registry\src\github.jparrowsec.cn-1ecc6299db9ec823\pyo3-build-config-0.16.3\src\lib.rs:75
    12: build_script_build::configure_pyo3
               at .\build.rs:43
    13: build_script_build::main
               at .\build.rs:56
    14: core::ops::function::FnOnce::call_once<void (*)(),tuple$<> >
               at /rustc/7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c\library\core\src\ops\function.rs:227
  note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
warning: build failed, waiting for other jobs to finish...

Your operating system and version

Windows 10, Version 2004

Your Python version (python --version)

Python 3.9.10

Your Rust version (rustc --version)

rustc 1.60.0 (7737e0b5c 2022-04-04)

Your PyO3 version

0.16.3

How did you install python? Did you use a virtualenv?

Python was installed using the python.org installer for windows.

I used a venv to build my project.

Additional Info

No response