Ed Page 83615cfa78

Setup cargo environment for cargo rustc --print (#15026) ...

It turns out, running `cargo rustc --print cfg -Zunstable-options` (and
the like, https://github.com/rust-lang/cargo/issues/9357) fail with
`.cargo/config.toml` setups like
```toml
[build]
# custom target json that lives in `./targets/my-super-cool-target.json`
target = "my-super-cool-target"

[env]
RUST_TARGET_PATH = { value = "./targets", relative = true }
```
resulting in
```

❯ cargo rustc --print cfg -Zunstable-options
error: Error loading target specification: Could not find specification for target "my-super-cool-target". Run `rustc --print target-list` for a list of built-in targets

error: process didn't exit successfully: `C:\Users\lukas\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\bin\rustc.exe --target my-super-cool-target --print cfg` (exit code: 1)
```

The reason for that is that cargo recognizes the target from the
`.cargo/config` and then implicitly passes that along to the spawned
rustc process, but it does so without passing along the important
environment that is required for the target tuple to make sense.

(can add a test if desired, just tell me where)

2025-01-07 18:39:52 +00:00

..

build-std

test: relax panic output assertion

2024-12-29 13:45:24 -05:00

testsuite

Setup cargo environment for cargo rustc --print (#15026)

2025-01-07 18:39:52 +00:00