Update application package name checks (#685)

* Add more checks to app name test + update error

* Fix type hint for RankProfileFields.inputs

* Support single dashes in Pyvespa app package name

* Update app package name test

tests/unit/test_package.py

@@ -1305,7 +1305,13 @@ def test_invalid_name(self):
         with pytest.raises(ValueError):
             ApplicationPackage(name="test_app")
         with pytest.raises(ValueError):
-            ApplicationPackage(name="test-app")
+            ApplicationPackage(name="test--app")
+        with pytest.raises(ValueError):
+            ApplicationPackage(name="42test-app")
+        with pytest.raises(ValueError):
+            ApplicationPackage(name="Test-app")
+        with pytest.raises(ValueError):
+            ApplicationPackage(name="test-app" + "x" * 20)
 
 
 class TestFieldAlias(unittest.TestCase):

vespa/package.py

@@ -2076,9 +2076,15 @@ def __init__(
         It will create a default :class:`Schema`, :class:`QueryProfile` and :class:`QueryProfileType` that you can then
         populate with specifics of your application.
         """
-        if not name.isalnum():
+        if not (
+            name[0].isalpha()
+            and name.islower()
+            and len(name) <= 20
+            and all(char.isalnum() or char == "-" for char in name)
+            and "--" not in name
+        ):
             raise ValueError(
-                "Application package name can only contain [a-zA-Z0-9], was '{}'".format(
+                "Application name must start with a letter, must be lowercase, can only contain [a-z0-9] and single dashes (not consecutive), and may contain no more than 20 characters, was '{}'".format(
                     name
                 )
             )