fix: empty paths result in root-relative error (#154)

Author: Yummy-Yums

crates/hm-dsl-engine/harmont-py/harmont/_rust.py

@@ -743,7 +743,9 @@ def _make_rust_project(
         components=components,
         base=base,
     )
-
+    # set empty file path to "." to prevent root-relative from happening
+    if not path:
+        path = "."
     lock_path = f"{path}/Cargo.lock" if path != "." else "Cargo.lock"
     toml_glob = f"{path}/**/Cargo.toml" if path != "." else "**/Cargo.toml"
     rs_glob = f"{path}/**/*.rs" if path != "." else "**/*.rs"

crates/hm-dsl-engine/harmont-py/tests/test_rust.py

@@ -3,9 +3,13 @@
 from __future__ import annotations
 
 import pytest
+import tempfile
 
 import harmont as hm
 from harmont.cache import CacheOnChange
+from harmont.keygen import resolve_pipeline_keys
+from pathlib import Path
+
 
 
 def _cmds(p: dict) -> list[str]:
@@ -328,6 +332,36 @@ def test_project_has_all_methods(self):
         assert proj.clippy().cmd is not None
         assert proj.fmt().cmd is not None
 
+
+    def test_empty_path_throws_error_is_caught(self):
+        proj = hm.rust.project(path="")
+        graph = {
+            "nodes":  [
+                    {
+                        "step": {
+                            "key": "a",
+                            "cmd": "cargo build",
+                            "cache": {"policy": "on_change", "paths": [p for p in list(proj.warmup.cache.paths)]},
+                        },
+                        "env": {},
+                    },
+                ],
+            "node_holes": [],
+            "edge_property": "directed",
+            "edges": [],
+        }
+     
+        with tempfile.TemporaryDirectory() as d:
+            res = resolve_pipeline_keys(
+                graph,
+                pipeline_org="default",
+                pipeline_slug="default",
+                now=0,
+                base_path=Path(d),
+                env={}
+            )
+            assert res['nodes'][0]['step']['cache']['key'] is not None
+
     def test_warmup_implicit_cache_on_change(self):
         proj = hm.rust.project(path="cli")
         assert proj.warmup.cache == CacheOnChange(