Fail if key is empty.

Author: a-feld

opentelemetry-api/src/opentelemetry/distributedcontext/__init__.py

@@ -49,7 +49,7 @@ def __new__(cls, value: str) -> "EntryKey":
 
     @staticmethod
     def create(value: str) -> "EntryKey":
-        if len(value) > 255 or any(c not in PRINTABLE for c in value):
+        if not 0 < len(value) <= 255 or any(c not in PRINTABLE for c in value):
             raise ValueError("Invalid EntryKey", value)
 
         return typing.cast(EntryKey, value)

opentelemetry-api/tests/distributedcontext/test_distributed_context.py

@@ -32,6 +32,10 @@ def test_entry_ttl_unlimited_propagation(self):
 
 
 class TestEntryKey(unittest.TestCase):
+    def test_create_empty(self):
+        with self.assertRaises(ValueError):
+            distributedcontext.EntryKey.create("")
+
     def test_create_too_long(self):
         with self.assertRaises(ValueError):
             distributedcontext.EntryKey.create("a" * 256)