chore: Cleanup cargo config queries

crates/project-model/src/cargo_config_file.rs

@@ -0,0 +1,34 @@
+//! Read `.cargo/config.toml` as a JSON object
+use rustc_hash::FxHashMap;
+use toolchain::Tool;
+
+use crate::{ManifestPath, Sysroot, utf8_stdout};
+
+pub(crate) type CargoConfigFile = serde_json::Map<String, serde_json::Value>;
+
+pub(crate) fn read(
+    manifest: &ManifestPath,
+    extra_env: &FxHashMap<String, Option<String>>,
+    sysroot: &Sysroot,
+) -> Option<CargoConfigFile> {
+    let mut cargo_config = sysroot.tool(Tool::Cargo, manifest.parent(), extra_env);
+    cargo_config
+        .args(["-Z", "unstable-options", "config", "get", "--format", "json"])
+        .env("RUSTC_BOOTSTRAP", "1");
+    if manifest.is_rust_manifest() {
+        cargo_config.arg("-Zscript");
+    }
+
+    tracing::debug!("Discovering cargo config by {:?}", cargo_config);
+    let json: serde_json::Map<String, serde_json::Value> = utf8_stdout(&mut cargo_config)
+        .inspect(|json| {
+            tracing::debug!("Discovered cargo config: {:?}", json);
+        })
+        .inspect_err(|err| {
+            tracing::debug!("Failed to discover cargo config: {:?}", err);
+        })
+        .ok()
+        .and_then(|stdout| serde_json::from_str(&stdout).ok())?;
+
+    Some(json)
+}