RUSTFLAGS undefine action

[starlitxiling]

Problem

I write .cargo/config.toml for my repo:

[target.aarch64-apple-darwin]
rustflags = [
    "-C", "link-arg=-mmacosx-version-min=${DEPLOYMENT_TARGET}",
    "-C", "link-arg=-isysroot",
    "-C", "link-arg=$(xcrun --sdk macosx --show-sdk-path)",
]

when i use cargo build {binary file name} --release,the compiled is failed.But when i use RUSTFLAGS="-v" cargo build {binary file name} --release,the compile is success.
I thought RUSTFLAGS="-v" is used to enable verbose output and does not change the variables during compilation, but why does the above line appear?

Steps

No response

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.85.0
release: 1.85.0
host: aarch64-apple-darwin
libgit2: 1.8.4 (sys:0.19.0 system)
libcurl: 8.7.1 (sys:0.4.74+curl-8.9.0 system ssl:(SecureTransport) LibreSSL/3.3.6)
os: Mac OS 15.2.0 [64-bit]

[weihanglo]

RUSTFLAGS overrides the configuration from build.rustflags. See

• the doc of build.rustflags
• Multiple rustflags configs should be cumulative #5376

And for "-C", "link-arg=$(xcrun --sdk macosx --show-sdk-path)", this won't work because rustflags will be passed to rustc directly. It won't get parsed by any shell program. See also

• Support environment variable expansion in config.toml #10789

[weihanglo]

Going to close this as the behavior is expected, and shell expansion support is discussed in #10789. If there is any reason this issue should keep open separately, let us know. Thank you.