feat: Dynamically determine latest init runtime

samcli/commands/init/interactive_init_flow.py

@@ -4,6 +4,7 @@
 
 import logging
 import pathlib
+import re
 import tempfile
 from typing import Optional, Tuple
 
@@ -28,6 +29,7 @@
 )
 from samcli.lib.config.samconfig import DEFAULT_CONFIG_FILE_NAME
 from samcli.lib.schemas.schemas_code_manager import do_download_source_code_binding, do_extract_and_merge_schemas_code
+from samcli.lib.utils.architecture import SUPPORTED_RUNTIMES
 from samcli.lib.utils.osutils import remove
 from samcli.lib.utils.packagetype import IMAGE, ZIP
 from samcli.local.common.runtime_template import (
@@ -323,6 +325,49 @@ def _generate_from_use_case(
         )
 
 
+def _get_latest_python_runtime() -> str:
+    """
+    Returns the latest support version of Python
+    SAM CLI supports
+
+    Returns
+    -------
+    str:
+        The name of the latest Python runtime (ex. "python3.12")
+    """
+
+    # set python3.9 as fallback
+    latest_major = 3
+    latest_minor = 9
+
+    compiled_regex = re.compile(r"python(.*?)\.(.*)")
+
+    for runtime in SUPPORTED_RUNTIMES:
+        if not runtime.startswith("python"):
+            continue
+
+        # python3.12 => 3.12 => (3, 12)
+        version_match = re.match(compiled_regex, runtime)
+
+        if not version_match:
+            LOG.debug(f"Failed to match version while checking {runtime}")
+            continue
+
+        matched_groups = version_match.groups()
+
+        try:
+            version_major = int(matched_groups[0])
+            version_minor = int(matched_groups[1])
+        except (ValueError, IndexError):
+            LOG.debug(f"Failed to parse version while checking {runtime}")
+            continue
+
+        latest_major = version_major if version_major > latest_major else latest_major
+        latest_minor = version_minor if version_minor > latest_minor else latest_minor
+
+    return f"python{latest_major}.{latest_minor}"
+
+
 def _generate_default_hello_world_application(
     use_case: str,
     package_type: Optional[str],
@@ -356,8 +401,10 @@ def _generate_default_hello_world_application(
     """
     is_package_type_image = bool(package_type == IMAGE)
     if use_case == "Hello World Example" and not (runtime or base_image or is_package_type_image or dependency_manager):
-        if click.confirm("\nUse the most popular runtime and package type? (Python and zip)"):
-            runtime, package_type, dependency_manager, pt_explicit = "python3.9", ZIP, "pip", True
+        latest_python = _get_latest_python_runtime()
+
+        if click.confirm(f"\nUse the most popular runtime and package type? ({latest_python} and zip)"):
+            runtime, package_type, dependency_manager, pt_explicit = _get_latest_python_runtime(), ZIP, "pip", True
     return (runtime, package_type, dependency_manager, pt_explicit)
 
 

tests/unit/commands/init/test_cli.py

@@ -3,6 +3,8 @@
 import shutil
 import subprocess
 import tempfile
+from unittest import mock
+from parameterized import parameterized
 import requests
 from pathlib import Path
 from typing import Dict, Any
@@ -25,7 +27,7 @@
     get_template_value,
     template_does_not_meet_filter_criteria,
 )
-from samcli.commands.init.interactive_init_flow import get_sorted_runtimes
+from samcli.commands.init.interactive_init_flow import _get_latest_python_runtime, get_sorted_runtimes
 from samcli.lib.init import GenerateProjectFailedError
 from samcli.lib.utils import osutils
 from samcli.lib.utils.git_repo import GitRepo
@@ -2006,9 +2008,9 @@ def test_init_cli_generate_default_hello_world_app(
         request_mock.side_effect = requests.Timeout()
         init_options_from_manifest_mock.return_value = [
             {
-                "directory": "python3.9/cookiecutter-aws-sam-hello-python",
+                "directory": "python3.12/cookiecutter-aws-sam-hello-python",
                 "displayName": "Hello World Example",
-                "dependencyManager": "npm",
+                "dependencyManager": "pip",
                 "appTemplate": "hello-world",
                 "packageType": "Zip",
                 "useCaseName": "Hello World Example",
@@ -2026,10 +2028,10 @@ def test_init_cli_generate_default_hello_world_app(
 
         get_preprocessed_manifest_mock.return_value = {
             "Hello World Example": {
-                "python3.9": {
+                "python3.12": {
                     "Zip": [
                         {
-                            "directory": "python3.9/cookiecutter-aws-sam-hello-python3.9",
+                            "directory": "python3.12/cookiecutter-aws-sam-hello-python3.12",
                             "displayName": "Hello World Example",
                             "dependencyManager": "pip",
                             "appTemplate": "hello-world",
@@ -2070,16 +2072,17 @@ def test_init_cli_generate_default_hello_world_app(
 
         runner = CliRunner()
         result = runner.invoke(init_cmd, input=user_input)
+        print(result.stdout)
         self.assertFalse(result.exception)
         generate_project_patch.assert_called_once_with(
             ANY,
             ZIP,
-            "python3.9",
+            "python3.12",
             "pip",
             ".",
             "test-project",
             True,
-            {"project_name": "test-project", "runtime": "python3.9", "architectures": {"value": ["x86_64"]}},
+            {"project_name": "test-project", "runtime": "python3.12", "architectures": {"value": ["x86_64"]}},
             False,
             False,
             False,
@@ -3193,3 +3196,30 @@ def test_init_cli_generate_app_template_provide_via_application_insights_options
             True,
             False,
         )
+
+    def test_latest_python_fetcher_returns_latest(self):
+        latest_python = "python3.100000"
+
+        with mock.patch(
+            "samcli.commands.init.interactive_init_flow.SUPPORTED_RUNTIMES",
+            {"python3.2": Any, latest_python: Any, "python3.14": Any},
+        ):
+            result = _get_latest_python_runtime()
+
+        self.assertEqual(result, latest_python)
+
+    @parameterized.expand(
+        [
+            ("dotnet3.1",),
+            ("foo bar",),
+            ("",),
+        ]
+    )
+    def test_latest_python_fetcher_fallback_invalid_runtime(self, invalid_runtime):
+        with mock.patch(
+            "samcli.commands.init.interactive_init_flow.SUPPORTED_RUNTIMES",
+            {invalid_runtime: Any},
+        ):
+            result = _get_latest_python_runtime()
+
+        self.assertEqual(result, "python3.9")