config: Deny CARGO_HOME in [env] table (fixes #11590)

src/cargo/util/config/mod.rs

@@ -1685,8 +1685,15 @@ impl Config {
  }
 
  pub fn env_config(&self) -> CargoResult<&EnvConfig> {
- self.env_config
- .try_borrow_with(|| self.get::<EnvConfig>("env"))
+ let env_config = self
+ .env_config
+ .try_borrow_with(|| self.get::<EnvConfig>("env"))?;
+
+ if env_config.get("CARGO_HOME").is_some() {
+ bail!("`CARGO_HOME` environment variable should be not be set in `.cargo/config` via `env.CARGO_HOME` as cargo does not use this value directly (only recursive calls to cargo would)");
+ }
+
+ Ok(env_config)
  }
 
  /// This is used to validate the `term` table has valid syntax.

tests/testsuite/cargo_env_config.rs

@@ -57,6 +57,32 @@ fn env_invalid() {
  .run();
 }
 
+#[cargo_test]
+fn env_no_cargo_home() {
+ let p = project()
+ .file("Cargo.toml", &basic_bin_manifest("foo"))
+ .file(
+ "src/main.rs",
+ r#"
+ fn main() {
+ }
+ "#,
+ )
+ .file(
+ ".cargo/config",
+ r#"
+ [env]
+ CARGO_HOME = "/"
+ "#,
+ )
+ .build();
+
+ p.cargo("build")
+ .with_status(101)
+ .with_stderr_contains("[..]`CARGO_HOME` environment variable should be not be set in `.cargo/config` via `env.CARGO_HOME` as cargo does not use this value directly (only recursive calls to cargo would)")
+ .run();
+}
+
 #[cargo_test]
 fn env_force() {
  let p = project()