gh-109653: Improve import preformance of tkinter library with lazy imports

Lib/test/test_tkinter/test_misc.py

@@ -11,6 +11,13 @@
 
 support.requires('gui')
 
+class TestTkImportTime(AbstractTkTest, unittest.TestCase):
+    @support.cpython_only
+    def test_lazy_imports(self):
+        support.import_helper.ensure_lazy_imports(
+            "tkinter", {"re", "os", "traceback"}
+        )
+
 class MiscTest(AbstractTkTest, unittest.TestCase):
 
     def test_all(self):

Lib/tkinter/__init__.py

@@ -29,16 +29,17 @@
 button.pack(side=BOTTOM)
 tk.mainloop()
 """
-
+import _tkinter # If this fails your Python may not be configured for Tk
+from tkinter.constants import *
 import collections
 import enum
 import sys
 import types
 
-import _tkinter # If this fails your Python may not be configured for Tk
+lazy import re
+lazy import traceback
+lazy import os
 TclError = _tkinter.TclError
-from tkinter.constants import *
-import re
 
 wantobjects = 1
 _debug = False  # set to True to print executed Tcl/Tk commands
@@ -50,22 +51,39 @@
 WRITABLE = _tkinter.WRITABLE
 EXCEPTION = _tkinter.EXCEPTION
 
+_magic_re = None
+_space_re = None
 
-_magic_re = re.compile(r'([\\{}])')
-_space_re = re.compile(r'([\s])', re.ASCII)
+def _get_magic_re():
+    """
+    Internal function that acts as a wrapper
+    for the re import to make it lazy.
+    """
+    global _magic_re
+    if _magic_re is None:
+        _magic_re = re.compile(r'([\\{}])')
+    return _magic_re
 
+def _get_space_re():
+    """
+    Internal function that acts as a wrapper
+    for the re import to make it lazy.
+    """
+    global _space_re
+    if _space_re is None:
+        _space_re = re.compile(r'([\s])', re.ASCII)
+    return _space_re
 
 def _join(value):
     """Internal function."""
     return ' '.join(map(_stringify, value))
 
-
 def _stringify(value):
     """Internal function."""
     if isinstance(value, (list, tuple)):
         if len(value) == 1:
             value = _stringify(value[0])
-            if _magic_re.search(value):
+            if _get_magic_re().search(value):
                 value = '{%s}' % value
         else:
             value = '{%s}' % _join(value)
@@ -76,14 +94,14 @@ def _stringify(value):
             value = str(value)
         if not value:
             value = '{}'
-        elif _magic_re.search(value):
+        elif _get_magic_re().search(value):
             # add '\' before special characters and spaces
-            value = _magic_re.sub(r'\\\1', value)
+            value = _get_magic_re().sub(r'\\\1', value)
             value = value.replace('\n', r'\n')
-            value = _space_re.sub(r'\\\1', value)
+            value = _get_space_re().sub(r'\\\1', value)
             if value[0] == '"':
                 value = '\\' + value
-        elif value[0] == '"' or _space_re.search(value):
+        elif value[0] == '"' or _get_space_re().search(value):
             value = '{%s}' % value
     return value
 
@@ -2526,7 +2544,6 @@ def __init__(self, screenName=None, baseName=None, className='Tk',
         # ensure that self.tk is always _something_.
         self.tk = None
         if baseName is None:
-            import os
             baseName = os.path.basename(sys.argv[0])
             baseName, ext = os.path.splitext(baseName)
             if ext not in ('.py', '.pyc'):
@@ -2586,7 +2603,6 @@ def readprofile(self, baseName, className):
         """Internal function. It reads .BASENAME.tcl and .CLASSNAME.tcl into
         the Tcl Interpreter and calls exec on the contents of .BASENAME.py and
         .CLASSNAME.py if such a file exists in the home directory."""
-        import os
         if 'HOME' in os.environ: home = os.environ['HOME']
         else: home = os.curdir
         class_tcl = os.path.join(home, '.%s.tcl' % className)
@@ -2609,7 +2625,6 @@ def report_callback_exception(self, exc, val, tb):
 
         Applications may want to override this internal function, and
         should when sys.stderr is None."""
-        import traceback
         print("Exception in Tkinter callback", file=sys.stderr)
         sys.last_exc = val
         sys.last_type = exc
@@ -5094,6 +5109,7 @@ def _test():
 
 __all__ = [name for name, obj in globals().items()
            if not name.startswith('_') and not isinstance(obj, types.ModuleType)
+           and not isinstance(obj, types.LazyImportType)
            and name not in {'wantobjects'}]
 
 if __name__ == '__main__':

Misc/NEWS.d/next/Library/2026-04-11-18-49-40.gh-issue-109653.VXU-w8.rst

@@ -0,0 +1,2 @@
+Reduce the import time of :mod:`tkinter` with lazy imports. Authored by Rihaan
+Meher in :gh:`148409`