fix: improve init naming

Author: drbh

docs/source/cli-init.md

@@ -47,15 +47,16 @@ kernels init my-user/my-kernel --overwrite
 `kernels init` prints suggested next steps after creating the project. A typical flow looks like:
 
 ```bash
-cd my_kernel
+cd my-kernel
 cachix use huggingface
 nix run -L --max-jobs 1 --cores 8 .#build-and-copy
 uv run example.py
 ```
 
 ## Notes
 
-- The `<repo>` part is normalized to lowercase, and `-` is replaced with `_`. For example, `my-user/My-Kernel` becomes a directory named `my_kernel` and a repo id `my-user/my_kernel`.
+- The `<repo>` part is normalized to lowercase with dashes preferred. For example, `my-user/My_Kernel` becomes a directory named `my-kernel` and a repo id `my-user/my-kernel`.
+- Python package names use underscores (e.g., `my_kernel`) since dashes are not valid in Python identifiers.
 - `--backends` can be one of: `cpu`, `cuda`, `metal`, `rocm`, `xpu`, `npu`, or `all`.
 - If the target directory already exists and is not empty, `kernels init` exits with an error unless `--overwrite` is set.
 - The project is initialized as a Git repo (via `git init`) because Nix flakes require it.

kernels/src/kernels/cli/init.py

@@ -23,13 +23,26 @@ def parse_kernel_name(value: str) -> NamedTuple:
     if "/" in name or "\\" in name:  # validate kernel name
         raise argparse.ArgumentTypeError("repo name cannot contain path separators")
 
-    name = name.lower().replace("-", "_")  # normalize name
-    RepoInfo = NamedTuple("RepoInfo", [("name", str), ("owner", str), ("repo_id", str)])
-    return RepoInfo(name=name, owner=owner, repo_id=f"{owner}/{name}")
+    # Display name uses dashes (for repo name, directory, build.toml name)
+    display_name = name.lower().replace("_", "-")
+    # Normalized name uses underscores (for Python package names)
+    normalized_name = name.lower().replace("-", "_")
+
+    RepoInfo = NamedTuple(
+        "RepoInfo",
+        [("name", str), ("normalized_name", str), ("owner", str), ("repo_id", str)],
+    )
+    return RepoInfo(
+        name=display_name,
+        normalized_name=normalized_name,
+        owner=owner,
+        repo_id=f"{owner}/{display_name}",
+    )
 
 
 def run_init(args: Namespace) -> None:
     kernel_name = args.kernel_name.name
+    normalized_name = args.kernel_name.normalized_name
     repo_id = args.kernel_name.repo_id
     backends = KNOWN_BACKENDS if "all" in args.backends else set(args.backends)
 
@@ -54,7 +67,9 @@ def run_init(args: Namespace) -> None:
     template_dir = Path(
         snapshot_download(repo_id=args.template_repo, repo_type="model")
     )
-    _init_from_local_template(template_dir, target_dir, kernel_name, repo_id)
+    _init_from_local_template(
+        template_dir, target_dir, kernel_name, normalized_name, repo_id
+    )
 
     if backends:
         _update_build_backends(target_dir / "build.toml", backends)
@@ -84,12 +99,13 @@ def _init_from_local_template(
     template_dir: Path,
     target_dir: Path,
     kernel_name: str,
+    normalized_name: str,
     repo_id: str,
 ) -> None:
     # Placeholder mappings
     replacements = {
         "__KERNEL_NAME__": kernel_name,
-        "__KERNEL_NAME_NORMALIZED__": kernel_name,
+        "__KERNEL_NAME_NORMALIZED__": normalized_name,
         "__REPO_ID__": repo_id,
     }
 

kernels/tests/test_init.py

@@ -16,6 +16,7 @@ def e2e_init(backends: list[str]) -> None:
         backends=backends,
         overwrite=False,
     )
+    expected_dir_name = "test-kernel"
     expected_normalized_name = "test_kernel"
     expected_backend_dirs = {
         Path(f"{expected_normalized_name}_{backend}") for backend in args.backends
@@ -43,8 +44,8 @@ def e2e_init(backends: list[str]) -> None:
         try:
             run_init(args)
 
-            # make sure normalized dir was created
-            target_dir = Path(tmpdir) / expected_normalized_name
+            # make sure dir was created
+            target_dir = Path(tmpdir) / expected_dir_name
             if not target_dir.exists():
                 raise AssertionError(f"Target directory was not created: {target_dir}")