Fix cargo_target_empty_cfg test with env var.

src/cargo/util/config/mod.rs

@@ -471,22 +471,25 @@ impl Config {
  pub fn target_dir(&self) -> CargoResult<Option<Filesystem>> {
  if let Some(dir) = &self.target_dir {
  Ok(Some(dir.clone()))
- } else if let Some(dir) = env::var_os("CARGO_TARGET_DIR") {
+ } else if let Some(dir) = self.env.get("CARGO_TARGET_DIR") {
  // Check if the CARGO_TARGET_DIR environment variable is set to an empty string.
- if dir.to_string_lossy() == "" {
- anyhow::bail!("the target directory is set to an empty string in the `CARGO_TARGET_DIR` environment variable")
+ if dir.is_empty() {
+ bail!(
+ "the target directory is set to an empty string in the \
+ `CARGO_TARGET_DIR` environment variable"
+ )
  }
 
  Ok(Some(Filesystem::new(self.cwd.join(dir))))
  } else if let Some(val) = &self.build_config()?.target_dir {
  let path = val.resolve_path(self);
 
  // Check if the target directory is set to an empty string in the config.toml file.
- if val.raw_value() == "" {
- anyhow::bail!(format!(
+ if val.raw_value().is_empty() {
+ bail!(
  "the target directory is set to an empty string in {}",
  val.value().definition
- ),)
+ )
  }
 
  Ok(Some(Filesystem::new(path)))