From 5adba7fcd52a2e90fba07ce62f7d2e31cc09b184 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois?= <francois@beafrancois.fr>
Date: Sun, 31 May 2026 11:22:26 +0200
Subject: [PATCH] perf(load): use libyaml CLoader when available

Base the TUM loaders (and the param-file load) on yaml.CLoader when
PyYAML is built with libyaml, falling back to the pure-Python Loader
otherwise. Same ParserError/ScannerError, same custom !include
constructors. YAML parse time ~8x lower; validation suite identical
(same verdicts, same 8 expected-fail tracebacks, post-exec SUCCESS).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/testium/interpreter/utils/include.py   | 4 ++--
 src/testium/interpreter/utils/test_init.py | 4 ++--
 src/testium/interpreter/utils/yaml_load.py | 7 +++++++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/testium/interpreter/utils/include.py b/src/testium/interpreter/utils/include.py
index 0fd3d3e..19bd0c6 100644
--- a/src/testium/interpreter/utils/include.py
+++ b/src/testium/interpreter/utils/include.py
@@ -6,10 +6,10 @@ from runtime.tum_except import ETUMFileError
 from interpreter.utils.template import template_to_test
 from copy import copy
 from interpreter.utils.globdict import global_dict
-from interpreter.utils.yaml_load import yaml_load
+from interpreter.utils.yaml_load import yaml_load, YAML_BASE_LOADER
 
 
-class TUMLoaderNoIncludes(yaml.Loader):
+class TUMLoaderNoIncludes(YAML_BASE_LOADER):
 
     def __init__(self, stream):
 
diff --git a/src/testium/interpreter/utils/test_init.py b/src/testium/interpreter/utils/test_init.py
index e8d4d87..8c0d483 100644
--- a/src/testium/interpreter/utils/test_init.py
+++ b/src/testium/interpreter/utils/test_init.py
@@ -11,7 +11,7 @@ import api.testium as tm
 import interpreter.utils.globdict as globdict
 import interpreter.utils.settings as prefs
 from interpreter.utils.paths import testium_path
-from interpreter.utils.yaml_load import yaml_load
+from interpreter.utils.yaml_load import yaml_load, YAML_BASE_LOADER
 from interpreter.utils import clear_recursively
 from runtime.tum_except import ETUMSyntaxError
 from interpreter.utils.params import expanse, eval_func_init
@@ -89,7 +89,7 @@ def locate_report_file(rep_file):
 def yamltodict(param_file, silent=True):
     # load of the file
     with open(param_file, "r") as fd:
-        dp = yaml_load(fd, param_file, yaml.Loader)
+        dp = yaml_load(fd, param_file, YAML_BASE_LOADER)
 
     if dp is None:
         tm.print_info(f"The YAML file '{param_file}' is empty.")
diff --git a/src/testium/interpreter/utils/yaml_load.py b/src/testium/interpreter/utils/yaml_load.py
index df6b82f..5f6e477 100644
--- a/src/testium/interpreter/utils/yaml_load.py
+++ b/src/testium/interpreter/utils/yaml_load.py
@@ -1,3 +1,4 @@
+import yaml
 from yaml.parser import ParserError
 from yaml import load, Loader
 from yaml.scanner import ScannerError
@@ -5,6 +6,12 @@ from api.testium import print_debug
 from runtime.tum_except import ETUMSyntaxError
 import io
 
+# Use the libyaml-backed loader (much faster parsing) when PyYAML was built
+# with it, falling back to the pure-Python loader otherwise. The C loader
+# raises the same ParserError/ScannerError and supports the same custom
+# constructors (!include) and construct_* helpers the TUM loaders rely on.
+YAML_BASE_LOADER = yaml.CLoader if getattr(yaml, "__with_libyaml__", False) else yaml.Loader
+
 
 def print_yaml(file: io.TextIOWrapper, file_name):
     """ Prints YAML file if debug mode is activated.