Make sure the kernel spec uses the path to Pixi (#66)

* Make sure the kernel spec uses the path to Pixi
Cache the Pixi path after a successful call to has_compatible_pixi

* Bump version to 0.6.6

* Use Optional instead of | for Python 3.9

* Clear cache before each test

Author: renan-r-santos

package.json

@@ -1,6 +1,6 @@
 {
     "name": "pixi-kernel",
-    "version": "0.6.5",
+    "version": "0.6.6",
     "description": "Jupyter kernels using Pixi for reproducible notebooks.",
     "keywords": [
         "kernel",

pixi_kernel/compatibility.py

@@ -1,7 +1,7 @@
 import shutil
 import sys
 from pathlib import Path
-from typing import Any
+from typing import Any, Optional
 
 from returns.result import Failure, Result, Success
 
@@ -43,6 +43,10 @@
 """
 
 
+# Cache for the Pixi path
+_pixi_path_cache: Optional[str] = None
+
+
 def get_config_file() -> Path:
     return Path.home() / ".config" / "pixi-kernel" / "config.toml"
 
@@ -55,6 +59,10 @@ def get_default_pixi_path() -> Path:
 
 
 def find_pixi_binary() -> Result[str, None]:
+    # Return cached result if available
+    if _pixi_path_cache is not None:
+        return Success(_pixi_path_cache)
+
     # 1. Check if the Pixi binary is available in the system PATH
     pixi_path = shutil.which("pixi")
     if pixi_path is not None:
@@ -82,6 +90,11 @@ def find_pixi_binary() -> Result[str, None]:
 
 
 async def has_compatible_pixi() -> Result[None, str]:
+    global _pixi_path_cache
+
+    if _pixi_path_cache is not None:
+        return Success(None)
+
     result = find_pixi_binary()
 
     if isinstance(result, Failure):
@@ -100,6 +113,8 @@ async def has_compatible_pixi() -> Result[None, str]:
         minimum_version = ".".join(map(str, MINIMUM_PIXI_VERSION))
         return Failure(PIXI_OUTDATED.format(minimum_version=minimum_version))
 
+    # We found a compatible Pixi binary, cache it
+    _pixi_path_cache = pixi_path
     return Success(None)
 
 

pixi_kernel/provisioner.py

@@ -8,6 +8,7 @@
 from jupyter_client.provisioning.local_provisioner import LocalProvisioner
 from returns.result import Failure
 
+from .compatibility import find_pixi_binary
 from .readiness import verify_env_readiness
 
 
@@ -80,8 +81,9 @@ async def pre_launch(self, **kwargs: Any) -> dict[str, Any]:
         pixi_environment = result.unwrap()
 
         # Update kernel spec command line arguments: `argv[:2] = ["pixi", "run"]`
+        pixi_path = find_pixi_binary().unwrap()
         argv = kernel_spec.argv
-        kernel_spec.argv = [*argv[:2], "--environment", environment_name, *argv[2:]]
+        kernel_spec.argv = [pixi_path, argv[1], "--environment", environment_name, *argv[2:]]
 
         # R kernel needs special treatment
         # https://github.com/renan-r-santos/pixi-kernel/issues/15

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pixi-kernel"
-version = "0.6.5"
+version = "0.6.6"
 description = "Jupyter kernels using Pixi for reproducible notebooks"
 license = { text = "MIT" }
 authors = [

tests/unit/conftest.py

@@ -21,6 +21,11 @@ def event_loop_policy(request: pytest.FixtureRequest):
         return request.param
 
 
+@pytest.fixture(autouse=True)
+def _clear_pixi_path_cache():
+    pixi_kernel.compatibility._pixi_path_cache = None
+
+
 @pytest.fixture
 def _patch_find_pixi_binary(monkeypatch: pytest.MonkeyPatch):
     monkeypatch.setattr(pixi_kernel.compatibility, "find_pixi_binary", lambda: Failure(None))

uv.lock

@@ -1724,11 +1724,11 @@ __metadata:
   linkType: hard
 
 "@types/react@npm:*":
-  version: 19.1.8
-  resolution: "@types/react@npm:19.1.8"
+  version: 19.1.9
+  resolution: "@types/react@npm:19.1.9"
   dependencies:
     csstype: ^3.0.2
-  checksum: 17e0c74d9c01214938fa805aaa8b97925bf3c5514e88fdf94bec42c0a6d4abbc63d4e30255db176f46fd7f0aa89f8085b9b2b2fa5abaffbbf7e5009386ada892
+  checksum: 531b1f40e7f93aade4385a56b73e98846ec482ac695ccb0d4da1fc53fa398564f71383cd120cf8b8a9a1ea95f207c3e042d145fa8bc26e4fa57d863459e53b29
   languageName: node
   linkType: hard
 
@@ -2386,9 +2386,9 @@ __metadata:
   linkType: hard
 
 "caniuse-lite@npm:^1.0.30001726":
-  version: 1.0.30001727
-  resolution: "caniuse-lite@npm:1.0.30001727"
-  checksum: 2bc6112f242701198a99c17713d4409be9b404d09005f34f351ec29a4ea46c054e7aa4982bc16f06b81b7a375cbc61c937e89650170cbce84db772a376ed3963
+  version: 1.0.30001731
+  resolution: "caniuse-lite@npm:1.0.30001731"
+  checksum: ecd2ad779f31011bef657c0104a08a780d9bb38ff8ad7aeeeaf196151be22c492de87f4a9c89a30ea4aa9575c5a39c85bf6bd56e89a4bf8259f54a4fbfc24a0d
   languageName: node
   linkType: hard