view: create node if doesn't exist

src/sqltrie/pygtrie.py

@@ -83,8 +83,11 @@ def view(self, key=None):
         if key is not None:
             kwargs["prefix"] = key
 
-        for ikey, value in self._trie.iteritems(**kwargs):
-            ret[ikey[len(key) :]] = value
+        try:
+            for ikey, value in self._trie.iteritems(**kwargs):
+                ret[ikey[len(key) :]] = value
+        except KeyError:
+            pass
 
         return ret
 

src/sqltrie/sqlite/sqlite.py

@@ -219,12 +219,16 @@ def view(  # type: ignore
             return self
 
         self.commit()
-        node = self._get_node(key)
+        try:
+            nid = self._get_node(key)["id"]
+        except KeyError:
+            nid = self._create_node(key)
+            self.commit()
 
         trie = SQLiteTrie()
         trie._path = self._path  # pylint: disable=protected-access
         trie._root_key = key  # pylint: disable=protected-access
-        trie._root_id = node["id"]  # pylint: disable=protected-access
+        trie._root_id = nid  # pylint: disable=protected-access
         return trie
 
     def items(self, prefix=None, shallow=False):

tests/test_sqltrie.py

@@ -117,3 +117,17 @@ def test_open(tmp_path):
 
     assert trie[("foo",)] == b"foo-value"
     assert trie[("foo", "bar", "baz")] == b"baz-value"
+
+
+@pytest.mark.parametrize("cls", [SQLiteTrie, PyGTrie])
+def test_view(cls):
+    trie = cls()
+
+    view = trie.view(("a",))
+    assert not list(view.items())
+
+    view = trie.view(("a", "b"))
+    assert not list(view.items())
+
+    view = trie.view(("a", "b", "c"))
+    assert not list(view.items())