feat(deps): add uv-backed package installer (#5987)

* feat(deps): add uv-backed package installer

* feat(deps): support package cache root

tests/test_uv_pip_compat.py

@@ -12,6 +12,62 @@ ROOT = Path(__file__).resolve().parents[1]
 WRAPPER = ROOT / "scripts" / "uv-pip-compat.sh"
 
 
+def run_wrapper_with_env(link_name: str, *args: str) -> tuple[list[str], dict[str, str]]:
+    with tempfile.TemporaryDirectory() as temp_dir:
+        temp_path = Path(temp_dir)
+        venv_bin = temp_path / "venv" / "bin"
+        venv_bin.mkdir(parents=True)
+        (venv_bin / "python").write_text("#!/bin/sh\nexit 0\n", encoding="utf-8")
+        (venv_bin / "python").chmod(0o755)
+
+        argv_file = temp_path / "argv.txt"
+        env_file = temp_path / "env.txt"
+        uv_bin = venv_bin / "uv"
+        uv_bin.write_text(
+            "#!/bin/sh\n"
+            f"for arg in \"$@\"; do printf '%s\\n' \"$arg\" >> '{argv_file}'; done\n"
+            "for name in HTTP_PROXY HTTPS_PROXY http_proxy https_proxy; do\n"
+            "  eval \"value=\\${$name:-}\"\n"
+            f"  printf '%s=%s\\n' \"$name\" \"$value\" >> '{env_file}'\n"
+            "done\n",
+            encoding="utf-8",
+        )
+        uv_bin.chmod(0o755)
+
+        wrapper_path = venv_bin / "uv-pip-compat"
+        shutil.copy2(WRAPPER, wrapper_path)
+        wrapper_path.chmod(0o755)
+        link_path = venv_bin / link_name
+        link_path.symlink_to(wrapper_path.name)
+
+        subprocess.run(
+            [str(link_path), *args],
+            check=True,
+            env={
+                **os.environ,
+                "PATH": f"{venv_bin}{os.pathsep}{os.environ.get('PATH', '')}",
+            },
+        )
+        env_lines = dict(line.split("=", 1) for line in env_file.read_text(encoding="utf-8").splitlines())
+        return argv_file.read_text(encoding="utf-8").splitlines(), env_lines
+
+
+def test_pip_install_converts_proxy_argument_to_env():
+    argv, env_lines = run_wrapper_with_env("pip", "install", "--proxy", "http://proxy.example:7890", "demo")
+
+    assert "--proxy" not in argv
+    assert "http://proxy.example:7890" not in argv
+    assert env_lines["HTTPS_PROXY"] == "http://proxy.example:7890"
+    assert env_lines["HTTP_PROXY"] == "http://proxy.example:7890"
+
+
+def test_pip_install_converts_proxy_equals_argument_to_env():
+    argv, env_lines = run_wrapper_with_env("pip", "install", "--proxy=http://proxy.example:7890", "demo")
+
+    assert "--proxy=http://proxy.example:7890" not in argv
+    assert env_lines["https_proxy"] == "http://proxy.example:7890"
+
+
 class UvPipCompatTests(unittest.TestCase):
     def run_wrapper(self, link_name: str, *args: str) -> list[str]:
         with tempfile.TemporaryDirectory() as temp_dir: