fix: make sure pyright is happy with external deps (#296)

Fixes #295

Author: coretl

template/pyproject.toml.jinja

@@ -103,7 +103,9 @@ description = "Run {{ type_checker }}"
 commands = [
     [
         "{{ type_checker }}",
-        "src",
+        {% if type_checker=="pyright" %}"--pythonpath",
+        ".venv/bin/python",
+        {% endif %}"src",
         "tests",
         { replace = "posargs", default = [
         ], extend = true },

tests/test_example.py

@@ -180,6 +180,8 @@ def test_example_repo_updates(tmp_path: Path):
     output = run(
         # Git directory expected to be different
         "diff -ur --exclude=.git "
+        # uv lock expected to be different
+        "--exclude=uv.lock "
         # The commit hash is different for some reason
         "--ignore-matching-lines='^_commit: ' "
         # If we tag an existing commit that has been pushed to main, then the copier
@@ -256,6 +258,27 @@ def test_pyright_works_in_standard_typing_mode(tmp_path: Path):
     run(f".venv/bin/pyright {tmp_path}")
 
 
+def test_pyright_works_with_external_deps(tmp_path: Path):
+    copy_project(tmp_path)
+    # Add an external dependency
+    pyproject_toml = tmp_path / "pyproject.toml"
+    text = pyproject_toml.read_text().replace(
+        "dependencies = []", 'dependencies = ["numpy"]'
+    )
+    pyproject_toml.write_text(text)
+    # And some code that uses it
+    src_file = tmp_path / "src" / "python_copier_template_example" / "example.py"
+    src_file.write_text("""
+import numpy as np
+
+def is_big(arr: np.ndarray) -> bool:
+    return arr.size > 0
+""")
+    # Ensure pyright is still happy
+    run = make_venv(tmp_path)
+    run(".venv/bin/tox -e type-checking")
+
+
 def test_ignores_mypy_strict_mode(tmp_path: Path):
     copy_project(tmp_path, type_checker="mypy", strict_typing=True)
     pyproject_toml = tmp_path / "pyproject.toml"