fix: upgrade LE expansion failure to WARNING, include exception in parameter warning

- _detect_foreach_code_changes: upgrade from debug to warning level so
  users see when ForEach code change detection is skipped
- _resolve_nested_stack_parameters: include exception message in the
  warning so users can diagnose without --debug

Author: bnusunny

samcli/lib/package/artifact_exporter.py

@@ -98,12 +98,14 @@ def _resolve_nested_stack_parameters(nested_params: Dict, parent_parameter_value
             # Expected: the nested-stack parameter references something the
             # resolver can't see at package time (e.g. a sibling resource).
             continue
-        except Exception:  # pylint: disable=broad-except
+        except Exception as e:  # pylint: disable=broad-except
             # Unexpected — likely a SAM CLI bug. Log with traceback so
             # --debug surfaces it; drop the value so packaging still proceeds.
             LOG.warning(
-                "Unexpected error resolving nested stack parameter %r; skipping. " "Run with --debug for details.",
+                "Unexpected error resolving nested stack parameter %r; skipping: %s. "
+                "Run with --debug for the full traceback.",
                 name,
+                e,
             )
             LOG.debug("Traceback for parameter %r resolution failure:", name, exc_info=True)
             continue

samcli/lib/sync/infra_sync_executor.py

@@ -589,7 +589,12 @@ def _detect_foreach_code_changes(
             current_expanded = expand_language_extensions(current_template).expanded_template
             deployed_expanded = expand_language_extensions(last_deployed_template).expanded_template
         except Exception:
-            LOG.debug("Failed to expand language extensions for code change detection, skipping", exc_info=True)
+            LOG.warning(
+                "Failed to expand language extensions for code change detection. "
+                "ForEach-generated resources will not be checked for code changes. "
+                "Run with --debug for details."
+            )
+            LOG.debug("Language extension expansion failure details:", exc_info=True)
             return
 
         current_resources = current_expanded.get("Resources", {})