Add version checker for UltraPlot

ultraplot/__init__.py

@@ -111,3 +111,7 @@
             warnings._warn_ultraplot(f"Invalid user rc file setting: {err}")
             _src[_key] = "black"  # fill value
 from .colors import _cmap_database as colormaps
+from .utils import check_for_update
+
+if rc["ultraplot.check_for_latest_version"]:
+    check_for_update("ultraplot")

ultraplot/internals/rcsetup.py

@@ -1945,6 +1945,11 @@ def copy(self):
         "The format string used to format `pint.Quantity` default unit labels "
         "using ``format(units, unitformat)``. See also :rcraw:`autoformat`.",
     ),
+    "ultraplot.check_for_latest_version": (
+        False,
+        _validate_bool,
+        "Whether to check for the latest version of UltraPlot on PyPI when importing",
+    ),
 }
 
 # Child settings. Changing the parent changes all the children, but

ultraplot/tests/test_config.py

@@ -32,3 +32,65 @@ def test_cycle_in_rc_file(tmp_path):
     uplt.rc.load(str(rc_file))
 
     assert uplt.rc["cycle"] == "colorblind"
+
+
+import io
+from unittest.mock import patch, MagicMock
+from importlib.metadata import PackageNotFoundError
+from ultraplot.utils import check_for_update
+
+
+@patch("builtins.print")
+@patch("importlib.metadata.version")
+def test_package_not_installed(mock_version, mock_print):
+    mock_version.side_effect = PackageNotFoundError
+    check_for_update("fakepkg")
+    mock_print.assert_not_called()
+
+
+@patch("builtins.print")
+@patch("importlib.metadata.version", return_value="1.0.0")
+@patch("urllib.request.urlopen")
+def test_network_failure(mock_urlopen, mock_version, mock_print):
+    mock_urlopen.side_effect = Exception("Network down")
+    check_for_update("fakepkg")
+    mock_print.assert_not_called()
+
+
+@patch("builtins.print")
+@patch("importlib.metadata.version", return_value="1.0.0")
+@patch("urllib.request.urlopen")
+def test_no_update_available(mock_urlopen, mock_version, mock_print):
+    mock_resp = MagicMock()
+    mock_resp.__enter__.return_value = io.StringIO('{"info": {"version": "1.0.0"}}')
+    mock_urlopen.return_value = mock_resp
+
+    check_for_update("fakepkg")
+    mock_print.assert_not_called()
+
+
+@patch("builtins.print")
+@patch("importlib.metadata.version", return_value="1.0.0")
+@patch("urllib.request.urlopen")
+def test_update_available(mock_urlopen, mock_version, mock_print):
+    mock_resp = MagicMock()
+    mock_resp.__enter__.return_value = io.StringIO('{"info": {"version": "1.2.0"}}')
+    mock_urlopen.return_value = mock_resp
+
+    check_for_update("fakepkg")
+    mock_print.assert_called_once()
+    msg = mock_print.call_args[0][0]
+    assert "A newer version of fakepkg is available" in msg
+    assert "1.0.0 → 1.2.0" in msg
+
+
+@patch("builtins.print")
+@patch("importlib.metadata.version", return_value="1.0.0dev")
+@patch("urllib.request.urlopen")
+def test_dev_version_skipped(mock_urlopen, mock_version, mock_print):
+    mock_resp = MagicMock()
+    mock_resp.__enter__.return_value = io.StringIO('{"info": {"version": "2.0.0"}}')
+    mock_urlopen.return_value = mock_resp
+
+    check_for_update("fakepkg")
+    mock_print.assert_not_called()

ultraplot/utils.py

@@ -1131,6 +1131,34 @@ def _check_ranges(
         return True
 
 
+def check_for_update(package_name: str) -> None:
+    import json
+    import urllib.request
+    from importlib.metadata import version, PackageNotFoundError
+
+    try:
+        current_version = version(package_name)
+    except PackageNotFoundError:
+        return  # package not installed (e.g. during dev)
+
+    try:
+        with urllib.request.urlopen(
+            f"https://pypi.org/pypi/{package_name}/json", timeout=2
+        ) as resp:
+            data = json.load(resp)
+            latest_version = data["info"]["version"]
+    except Exception:
+        return  # fail silently, e.g. no internet
+
+    # Skip local dev versions
+    if latest_version != current_version and "dev" not in current_version:
+        print(
+            f"\033[93m⚠️  A newer version of {package_name} is available: "
+            f"{current_version} → {latest_version}\n"
+            f"Run: pip install -U {package_name}\033[0m"
+        )
+
+
 # Deprecations
 shade, saturate = warnings._rename_objs(
     "0.6.0",