fix: Do not resolve build-dir if template variables are present

Author: ranger-ross

src/easy.rs

@@ -514,6 +514,9 @@ pub struct BuildConfig {
     /// specified is the value of build.target-dir
     ///
     /// [Cargo Reference](https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#build-dir)
+    ///
+    /// **Note:** If a template variable is used the path will be unresolved. For available template
+    /// variables see the Cargo reference.
     #[cfg(feature = "unstable")]
     #[serde(skip_serializing_if = "Option::is_none")]
     pub build_dir: Option<PathBuf>,
@@ -582,7 +585,16 @@ impl BuildConfig {
         });
         let target_dir = de.target_dir.map(|v| v.resolve_as_path(current_dir).into_owned());
         #[cfg(feature = "unstable")]
-        let build_dir = de.build_dir.map(|v| v.resolve_as_path(current_dir).into_owned());
+        let build_dir = de.build_dir.map(|v| {
+            if v.val.starts_with("{workspace-root}")
+                || v.val.starts_with("{cargo-cache-home}")
+                || v.val.contains("{workspace-path-hash}")
+            {
+                return PathBuf::from(v.val);
+            }
+
+            v.resolve_as_path(current_dir).into_owned()
+        });
         let de_rustflags = de.rustflags.clone();
         let rustflags =
             de.rustflags.map(|v| Flags { flags: v.flags.into_iter().map(|v| v.val).collect() });