gh-124188: Fix PyErr_ProgramTextObject() (GH-124189)

* Detect source file encoding.
* Use the "replace" error handler even for UTF-8 (default) encoding.
* Remove the BOM.
* Fix detection of too long lines if they contain NUL.
* Return the head rather than the tail for truncated long lines.

1 files changed, 7 insertions, 3 deletions

diff --git a/Lib/test/support/script_helper.py b/Lib/test/support/script_helper.py
index d0be317..46ce950 100644
--- a/Lib/test/support/script_helper.py
+++ b/Lib/test/support/script_helper.py
@@ -234,9 +234,13 @@ def make_script(script_dir, script_basename, source, omit_suffix=False):
     if not omit_suffix:
         script_filename += os.extsep + 'py'
     script_name = os.path.join(script_dir, script_filename)
-    # The script should be encoded to UTF-8, the default string encoding
-    with open(script_name, 'w', encoding='utf-8') as script_file:
-        script_file.write(source)
+    if isinstance(source, str):
+        # The script should be encoded to UTF-8, the default string encoding
+        with open(script_name, 'w', encoding='utf-8') as script_file:
+            script_file.write(source)
+    else:
+        with open(script_name, 'wb') as script_file:
+            script_file.write(source)
     importlib.invalidate_caches()
     return script_name