fix(event): remove max length restriction for extension attributes

Remove the 20-character maximum length restriction for extension attribute names in both v03 and v1 event versions. Update validation error messages and add tests to ensure compatibility with longer attribute names.

Signed-off-by: Yurii Serhiichuk <savik.ne@gmail.com>

Author: xSAVIKx

src/cloudevents/core/v03/event.py

@@ -267,11 +267,11 @@ def _validate_extension_attributes(
                         msg="Extension attribute 'data' is reserved and must not be used",
                     )
                 )
-            if not (1 <= len(extension_attribute) <= 20):
+            if not (1 <= len(extension_attribute)):
                 errors[extension_attribute].append(
                     CustomExtensionAttributeError(
                         attribute_name=extension_attribute,
-                        msg=f"Extension attribute '{extension_attribute}' should be between 1 and 20 characters long",
+                        msg=f"Extension attribute name must be at least 1 character long but was '{extension_attribute}'",
                     )
                 )
             if not re.match(r"^[a-z0-9]+$", extension_attribute):

src/cloudevents/core/v1/event.py

@@ -252,11 +252,11 @@ def _validate_extension_attributes(
                         msg="Extension attribute 'data' is reserved and must not be used",
                     )
                 )
-            if not (1 <= len(extension_attribute) <= 20):
+            if not (1 <= len(extension_attribute)):
                 errors[extension_attribute].append(
                     CustomExtensionAttributeError(
                         attribute_name=extension_attribute,
-                        msg=f"Extension attribute '{extension_attribute}' should be between 1 and 20 characters long",
+                        msg=f"Extension attribute name must be at least 1 character long but was '{extension_attribute}'",
                     )
                 )
             if not re.match(r"^[a-z0-9]+$", extension_attribute):

tests/test_core/test_v03/test_event.py

@@ -410,7 +410,7 @@ def test_required_attributes_null_or_empty(
                     str(
                         CustomExtensionAttributeError(
                             "",
-                            "Extension attribute '' should be between 1 and 20 characters long",
+                            "Extension attribute name must be at least 1 character long but was ''",
                         )
                     ),
                     str(
@@ -422,19 +422,6 @@ def test_required_attributes_null_or_empty(
                 ]
             },
         ),
-        (
-            "thisisaverylongextension",
-            {
-                "thisisaverylongextension": [
-                    str(
-                        CustomExtensionAttributeError(
-                            "thisisaverylongextension",
-                            "Extension attribute 'thisisaverylongextension' should be between 1 and 20 characters long",
-                        )
-                    )
-                ]
-            },
-        ),
         (
             "data",
             {
@@ -468,6 +455,21 @@ def test_custom_extension(extension_name: str, expected_error: dict) -> None:
     assert actual_errors == expected_error
 
 
+def test_long_extension_attribute_name() -> None:
+    # Verify that extension attribute names longer than 20 characters are allowed
+    long_name = "a" * 21
+    event = CloudEvent(
+        {
+            "id": "1",
+            "source": "/",
+            "type": "test",
+            "specversion": "0.3",
+            long_name: "value",
+        }
+    )
+    assert event.get_extension(long_name) == "value"
+
+
 def test_default_specversion() -> None:
     event = CloudEvent(
         attributes={"source": "/source", "type": "test", "id": "1"},

tests/test_core/test_v1/test_event.py

@@ -346,7 +346,7 @@ def test_required_attributes_null_or_empty(
                     str(
                         CustomExtensionAttributeError(
                             "",
-                            "Extension attribute '' should be between 1 and 20 characters long",
+                            "Extension attribute name must be at least 1 character long but was ''",
                         )
                     ),
                     str(
@@ -358,19 +358,6 @@ def test_required_attributes_null_or_empty(
                 ]
             },
         ),
-        (
-            "thisisaverylongextension",
-            {
-                "thisisaverylongextension": [
-                    str(
-                        CustomExtensionAttributeError(
-                            "thisisaverylongextension",
-                            "Extension attribute 'thisisaverylongextension' should be between 1 and 20 characters long",
-                        )
-                    )
-                ]
-            },
-        ),
         (
             "data",
             {
@@ -404,6 +391,21 @@ def test_custom_extension(extension_name: str, expected_error: dict) -> None:
     assert actual_errors == expected_error
 
 
+def test_long_extension_attribute_name() -> None:
+    # Verify that extension attribute names longer than 20 characters are allowed
+    long_name = "a" * 21
+    event = CloudEvent(
+        {
+            "id": "1",
+            "source": "/",
+            "type": "test",
+            "specversion": "1.0",
+            long_name: "value",
+        }
+    )
+    assert event.get_extension(long_name) == "value"
+
+
 def test_default_specversion() -> None:
     event = CloudEvent(
         attributes={"source": "/source", "type": "test", "id": "1"},