Relevant code here: https://hg.python.org/cpython/file/f254ceec0d45/Objects/codeobject.c#l72 https://hg.python.org/cpython/file/f254ceec0d45/Objects/code... I

Relevant code here: https://hg.python.org/cpython/file/f254ceec0d45/Objects/codeobject.c#l72 https://hg.python.org/cpython/file/f254ceec0d45/Objects/code... Its not actually length, its whether the string looks like it could be a python name, and it only happens for string literals.