added a bunch of assertions and debug comments to track down where th…

…e OS error in CI is comming from precicely

martin/build.rs

@@ -1,16 +1,27 @@
+#[cfg(feature = "webui")]
 /// copies a directory and its contents to a new location recursively
 fn copy_dir_all(
     src: impl AsRef<std::path::Path>,
     dst: impl AsRef<std::path::Path>,
+    exclude_dirs: &[std::path::PathBuf],
 ) -> std::io::Result<()> {
+    assert!(!exclude_dirs.contains(&src.as_ref().to_path_buf()));
+    assert!(src.as_ref().is_dir(), "source for the copy operation is not an existing directory");
+    assert!(!dst.as_ref().exists(), "destination for the copy operation must not exist");
     std::fs::create_dir_all(&dst)?;
+
     for entry in std::fs::read_dir(src)? {
         let entry = entry?;
         let ty = entry.file_type()?;
+        let src_path = entry.path();
+        let dst_path = dst.as_ref().join(entry.file_name());
         if ty.is_dir() {
-            copy_dir_all(entry.path(), dst.as_ref().join(entry.file_name()))?;
+            if exclude_dirs.contains(&src_path) {
+                continue;
+            }
+            copy_dir_all(src_path, &dst_path, exclude_dirs)?;
         } else {
-            std::fs::copy(entry.path(), dst.as_ref().join(entry.file_name()))?;
+            std::fs::copy(src_path, dst_path)?;
         }
     }
     Ok(())
@@ -25,15 +36,23 @@ fn main() -> std::io::Result<()> {
         // - move the frontend code to the OUT_DIR,
         // - install npm dependencies and
         // - build the frontend
+        let martin_ui_dir = std::path::PathBuf::from("martin-ui");
+        assert!(martin_ui_dir.is_dir(), "martin-ui directory does not exist");
         let out_dir = std::env::var("OUT_DIR")
             .unwrap()
             .parse::<std::path::PathBuf>()
             .unwrap();
-        let new_dir = out_dir.join("martin-ui");
-        let target_to_keep = std::path::PathBuf::from("martin-ui").join("dist");
-        copy_dir_all("martin-ui", &new_dir)?;
+        let out_martin_ui_dir = out_dir.join("martin-ui");
+        if out_martin_ui_dir.exists() {
+            std::fs::remove_dir_all(&out_martin_ui_dir)?;
+        }
+        copy_dir_all(&martin_ui_dir, &out_martin_ui_dir, &[martin_ui_dir.join("dist"), martin_ui_dir.join("node_modules")])?;
+
+        let target_to_keep = martin_ui_dir.join("dist");
+        assert!(!target_to_keep.exists() || target_to_keep.is_dir(), "the martin-ui/dist must either not exist or have been produced by previous builds");
 
-        static_files::NpmBuild::new(&new_dir)
+        println!("installing and building in {out_martin_ui_dir:?}");
+        static_files::NpmBuild::new(&out_martin_ui_dir)
             .install()?
             .run("build")?
             .target(&target_to_keep)
@@ -43,7 +62,8 @@ fn main() -> std::io::Result<()> {
         //
         // `copy_dir_all` was never anticipated by the crate we use
         // => we need to do this with different arguments.
-        static_files::NpmBuild::new("martin-ui")
+        println!("success -> change_detection");
+        static_files::NpmBuild::new(martin_ui_dir)
             .target(&target_to_keep)
             .change_detection();
     }