bender-slang: Cannonicalize include paths on windows

Author: fischeti

Cargo.lock

@@ -7,6 +7,9 @@ edition = "2024"
 cxx = "1.0.194"
 thiserror = "2.0.12"
 
+[target.'cfg(windows)'.dependencies]
+dunce = "1.0.4"
+
 [build-dependencies]
 cmake = "0.1.57"
 cxx-build = "1.0.194"

crates/bender-slang/Cargo.toml

@@ -150,7 +150,7 @@ impl SlangSession {
         defines: &[String],
     ) -> Result<Vec<usize>> {
         let files_vec = files.to_vec();
-        let includes_vec = includes.to_vec();
+        let includes_vec = normalize_include_dirs(includes)?;
         let defines_vec = defines.to_vec();
 
         let start = self.tree_count();
@@ -220,3 +220,23 @@ impl Default for SlangSession {
         Self::new()
     }
 }
+
+#[cfg(windows)]
+fn normalize_include_dirs(includes: &[String]) -> Result<Vec<String>> {
+    let mut out = Vec::with_capacity(includes.len());
+    for include in includes {
+        let canonical = dunce::canonicalize(include).map_err(|cause| SlangError::ParseGroup {
+            message: format!(
+                "Failed to canonicalize include directory '{}': {}",
+                include, cause
+            ),
+        })?;
+        out.push(canonical.to_string_lossy().into_owned());
+    }
+    Ok(out)
+}
+
+#[cfg(not(windows))]
+fn normalize_include_dirs(includes: &[String]) -> Result<Vec<String>> {
+    Ok(includes.to_vec())
+}