Improve import time of pprint

python · hugovk · Aug 7, 2024 · Aug 5, 2024 · Aug 6, 2024 · Aug 6, 2024
commit c9533e6bb7f5302c2e5989ed39de889d239571cc
diff --git a/Lib/pprint.py b/Lib/pprint.py
@@ -35,8 +35,6 @@
 """

 import collections as _collections
-import dataclasses as _dataclasses
-import re
 import sys as _sys
 import types as _types
 from io import StringIO as _StringIO
@@ -179,6 +177,9 @@ def _format(self, object, stream, indent, allowance, context, level):
        max_width = self._width - indent - allowance
        if len(rep) > max_width:
            p = self._dispatch.get(type(object).__repr__, None)
+            # Lazy import to improve module import time
+            import dataclasses as _dataclasses
+
            if p is not None:
                context[objid] = 1
                p(self, object, stream, indent, allowance, context, level + 1)
@@ -197,6 +198,9 @@ def _format(self, object, stream, indent, allowance, context, level):
        stream.write(rep)

    def _pprint_dataclass(self, object, stream, indent, allowance, context, level):
+        # Lazy import to improve module import time
+        import dataclasses as _dataclasses
+
        cls_name = object.__class__.__name__
        indent += len(cls_name) + 1
        items = [(f.name, getattr(object, f.name)) for f in _dataclasses.fields(object) if f.repr]
@@ -291,6 +295,9 @@ def _pprint_str(self, object, stream, indent, allowance, context, level):
            if len(rep) <= max_width1:
                chunks.append(rep)
            else:
+                # Lazy import to improve module import time
+                import re
+
                # A list of alternating (non-space, space) strings
                parts = re.findall(r'\S*\s*', line)
                assert parts