Detect case insensitive splat directories

src/ctx.rs

@@ -180,7 +180,7 @@ impl Ctx {
         let crt_ft = parking_lot::Mutex::new(None);
         let atl_ft = parking_lot::Mutex::new(None);
 
-        let splat_config = match &ops {
+        let mut splat_config = match &ops {
             crate::Ops::Splat(config) => {
                 let splat_roots = crate::splat::prep_splat(
                     self.clone(),
@@ -215,6 +215,26 @@ impl Ctx {
             _ => None,
         };
 
+        // Detect if the output root directory is case sensitive or not,
+        // if it's not, disable symlinks as they won't work
+        if let Some((root, enable_symlinks)) = splat_config.as_mut().and_then(|(sr, c)| {
+            c.enable_symlinks
+                .then_some((&sr.root, &mut c.enable_symlinks))
+        }) {
+            let test_path = root.join("BIG.xwin");
+            std::fs::write(&test_path, "").with_context(|| {
+                format!("failed to write case-sensitivity test file {test_path}")
+            })?;
+
+            if std::fs::read(root.join("big.xwin")).is_ok() {
+                *enable_symlinks = false;
+                tracing::warn!("detected splat root '{root}' is on a case-sensitive file system, disabling symlinks");
+            }
+
+            // Will be ugly but won't harm anything if file is left
+            let _ = std::fs::remove_file(test_path);
+        }
+
         let map = if let Some(map) = splat_config.as_ref().and_then(|(_, sp)| sp.map.as_ref()) {
             match std::fs::read_to_string(map) {
                 Ok(m) => Some(