From 5d67497eed0306a06066e271bc2d1d5a41597235 Mon Sep 17 00:00:00 2001
From: Jonathan Tatum <jdtatum@google.com>
Date: Tue, 10 Nov 2026 14:29:22 -0800
Subject: [PATCH] Treat an unspecified extension version as version 0 in
 cel::Config and the env YAML parser, consistent with cel-go and cel-java.

PiperOrigin-RevId: 1018554912
---
 cel_expr_python/cel_env_test.py        | 6 +++++-
 cel_expr_python/py_cel_env_internal.cc | 4 +---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/cel_expr_python/cel_env_test.py b/cel_expr_python/cel_env_test.py
index 9c5e924..43a5460 100644
--- a/cel_expr_python/cel_env_test.py
+++ b/cel_expr_python/cel_env_test.py
@@ -435,7 +435,6 @@ def test_config_export_extension_version(self):
           extensions:
             - name: "bindings"
             - name: "math"
-              version: 0
             - name: "optional"
               version: 1
             - name: "strings"
@@ -469,7 +468,9 @@ def test_config_extensions(self):
     config: cel.EnvConfig = cel.NewEnvConfigFromYaml("""
       extensions:
         - name: math
+          version: latest
         - name: strings
+          version: latest
       """)
     env: cel.Env = cel.NewEnv(
         config=config,
@@ -481,7 +482,9 @@ def test_config_extensions(self):
         normalize_yaml("""
           extensions:
             - name: "math"
+              version: latest
             - name: "strings"
+              version: latest
             - name: "test_cel_extension"
         """),
     )
@@ -494,6 +497,7 @@ def test_standard_extensions_via_config(self):
     config: cel.EnvConfig = cel.NewEnvConfigFromYaml("""
       extensions:
         - name: lists
+          version: latest
         - name: sets
         - name: two-var-comprehensions
         - name: optional
diff --git a/cel_expr_python/py_cel_env_internal.cc b/cel_expr_python/py_cel_env_internal.cc
index 7983bfe..48cdd53 100644
--- a/cel_expr_python/py_cel_env_internal.cc
+++ b/cel_expr_python/py_cel_env_internal.cc
@@ -176,9 +176,7 @@ PyCelEnvInternal::NewCelEnvInternal(
       name = extension->name();
     }
     CEL_PYTHON_RETURN_IF_ERROR(config.AddExtensionConfig(
-        name, extension->version() >= 0
-                  ? extension->version()
-                  : cel::Config::ExtensionConfig::kLatest));
+        name, extension->version() >= 0 ? extension->version() : 0));
     extension_handles.push_back(std::move(handle));
   }