https://github.com/python/cpython/commit/230917f5072c5c6b9373374a84d52935d7afa3b5
commit: 230917f5072c5c6b9373374a84d52935d7afa3b5
branch: main
author: Harjoth Khara <[email protected]>
committer: itamaro <[email protected]>
date: 2026-10-10T12:56:51-07:00
summary:
gh-141276: Avoid compiling zipimport source in get_filename (#153799)
`zipimporter.get_filename()` compiled source modules just to work out the
module's file name. `find_spec()` calls it through `spec_from_loader()`, so
importing a source module from a ZIP archive compiled it twice and emitted
every `SyntaxWarning` twice.
`get_filename()` now returns before reading or compiling the source.
As a result, a `SyntaxError` in a zipped source module is now raised by
`exec_module()` rather than by `find_spec()` or `get_filename()`, and
the source isn't compiled twice during import, which matches
the filesystem-based loaders.
files:
A Misc/NEWS.d/next/Library/2026-07-15-21-45-33.gh-issue-141276.xH7qP2.rst
M Doc/library/zipimport.rst
M Lib/test/test_cmd_line_script.py
M Lib/test/test_zipimport.py
M Lib/test/test_zipimport_support.py
M Lib/zipimport.py
diff --git a/Doc/library/zipimport.rst b/Doc/library/zipimport.rst
index a4136733a550301..c4a0df1d0314d0c 100644
--- a/Doc/library/zipimport.rst
+++ b/Doc/library/zipimport.rst
@@ -124,7 +124,7 @@ zipimporter Objects
Return the value ``__file__`` would be set to if the specified module
was imported. Raise :exc:`ZipImportError` if the module couldn't be
- imported.
+ found.
.. versionadded:: 3.1
diff --git a/Lib/test/test_cmd_line_script.py b/Lib/test/test_cmd_line_script.py
index 3802ed62ce7c26b..4b09eb76cbb3792 100644
--- a/Lib/test/test_cmd_line_script.py
+++ b/Lib/test/test_cmd_line_script.py
@@ -846,7 +846,7 @@ def test_zipfile_run_filter_syntax_warnings_by_module(self):
'-Werror:::test_pkg.__main__',
os.path.join(zip_name, 'test_pkg')
)
- self.assertEqual(err.count(b': SyntaxWarning: '), 12)
+ self.assertEqual(err.count(b': SyntaxWarning: '), 6)
def tearDownModule():
diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index 76cd85709a63af8..021fae1bd298e03 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -9,6 +9,7 @@
import time
import unittest
import unittest.mock
+import warnings
from test import support
from test.support import import_helper
@@ -229,6 +230,81 @@ def testPy(self):
files = {TESTMOD + ".py": test_src}
self.doTest(".py", files, TESTMOD)
+ def test_syntax_warning(self):
+ files = {TESTMOD + ".py": "x = 1 is 1\n"}
+ self.makeZip(files)
+ zi = zipimport.zipimporter(TEMP_ZIP)
+
+ with warnings.catch_warnings(record=True) as caught:
+ warnings.simplefilter("always", SyntaxWarning)
+ spec = zi.find_spec(TESTMOD)
+ self.assertIsNotNone(spec)
+ self.assertEqual(caught, [])
+
+ mod = importlib.util.module_from_spec(spec)
+ spec.loader.exec_module(mod)
+
+ self.assertEqual(len(caught), 1)
+ self.assertIsInstance(caught[0].message, SyntaxWarning)
+
+ def test_syntax_error_defers_to_exec(self):
+ files = {TESTMOD + ".py": "x =\n"}
+ self.makeZip(files)
+ zi = zipimport.zipimporter(TEMP_ZIP)
+ expected_path = os.path.join(TEMP_ZIP, TESTMOD + ".py")
+
+ spec = zi.find_spec(TESTMOD)
+ self.assertIsNotNone(spec)
+ self.assertEqual(spec.origin, expected_path)
+ self.assertEqual(zi.get_filename(TESTMOD), expected_path)
+
+ mod = importlib.util.module_from_spec(spec)
+ with self.assertRaises(SyntaxError):
+ spec.loader.exec_module(mod)
+
+ def test_get_filename_no_warnings(self):
+ files = {TESTMOD + ".py": "x = 1 is 1\n"}
+ self.makeZip(files)
+ zi = zipimport.zipimporter(TEMP_ZIP)
+
+ with warnings.catch_warnings(record=True) as caught:
+ warnings.simplefilter("always", SyntaxWarning)
+ zi.get_filename(TESTMOD)
+
+ self.assertEqual(caught, [])
+
+ def test_syntax_error_in_source_with_valid_pyc(self):
+ bad_src = "x =\n"
+ files = {TESTMOD + ".py": bad_src,
+ TESTMOD + pyc_ext: make_pyc(test_co, NOW, len(bad_src))}
+ self.makeZip(files)
+ zi = zipimport.zipimporter(TEMP_ZIP)
+ expected_path = os.path.join(TEMP_ZIP, TESTMOD + pyc_ext)
+
+ spec = zi.find_spec(TESTMOD)
+ self.assertIsNotNone(spec)
+ self.assertEqual(spec.origin, expected_path)
+
+ mod = importlib.util.module_from_spec(spec)
+ spec.loader.exec_module(mod)
+ self.assertEqual(mod.get_file(), expected_path)
+
+ def test_syntax_error_in_package_init_no_fallthrough(self):
+ packdir = TESTPACK + os.sep
+ files = {packdir + "__init__.py": "x =\n",
+ TESTPACK + ".py": test_src}
+ self.makeZip(files)
+ zi = zipimport.zipimporter(TEMP_ZIP)
+ expected_path = os.path.join(TEMP_ZIP, TESTPACK, "__init__.py")
+
+ spec = zi.find_spec(TESTPACK)
+ self.assertIsNotNone(spec)
+ self.assertEqual(spec.origin, expected_path)
+
+ mod = importlib.util.module_from_spec(spec)
+ with self.assertRaises(SyntaxError):
+ spec.loader.exec_module(mod)
+
def testPyc(self):
files = {TESTMOD + pyc_ext: test_pyc}
self.doTest(pyc_ext, files, TESTMOD)
diff --git a/Lib/test/test_zipimport_support.py
b/Lib/test/test_zipimport_support.py
index 2b28f46149b4ff3..dee5db00530ba34 100644
--- a/Lib/test/test_zipimport_support.py
+++ b/Lib/test/test_zipimport_support.py
@@ -253,7 +253,7 @@ def test_import_filter_syntax_warnings_by_module(self):
warnings.filterwarnings('error', module='test_mod')
import test_pkg.test_mod
self.assertEqual(sorted(wm.lineno for wm in wlog),
- sorted([4, 7, 10, 13, 14, 21]*2))
+ [4, 7, 10, 13, 14, 21])
filename = test_pkg.test_mod.__file__
for wm in wlog:
self.assertEqual(wm.filename, filename)
diff --git a/Lib/zipimport.py b/Lib/zipimport.py
index 19279d1c2bea368..241af9a0430684e 100644
--- a/Lib/zipimport.py
+++ b/Lib/zipimport.py
@@ -159,11 +159,12 @@ def get_filename(self, fullname):
"""get_filename(fullname) -> filename string.
Return the filename for the specified module or raise ZipImportError
- if it couldn't be imported.
+ if it couldn't be found.
"""
# Deciding the filename requires working out where the code
# would come from if the module was actually loaded
- code, ispackage, modpath = _get_module_code(self, fullname)
+ _, _, modpath = _get_module_code(
+ self, fullname, compile_source=False)
return modpath
@@ -793,9 +794,9 @@ def _get_pyc_source(self, path):
return _get_data(self.archive, toc_entry)
-# Get the code object associated with the module specified by
-# 'fullname'.
-def _get_module_code(self, fullname):
+# Get the code object associated with the module specified by 'fullname'.
+# If compile_source is false, return None for source code without reading or
compiling it.
+def _get_module_code(self, fullname, *, compile_source=True):
path = _get_module_path(self, fullname)
import_error = None
for suffix, isbytecode, ispackage in _zip_searchorder:
@@ -807,6 +808,8 @@ def _get_module_code(self, fullname):
pass
else:
modpath = toc_entry[0]
+ if not isbytecode and not compile_source:
+ return None, ispackage, modpath
data = _get_data(self.archive, toc_entry)
code = None
if isbytecode:
@@ -820,7 +823,6 @@ def _get_module_code(self, fullname):
# bad magic number or non-matching mtime
# in byte code, try next
continue
- modpath = toc_entry[0]
return code, ispackage, modpath
else:
if import_error:
diff --git
a/Misc/NEWS.d/next/Library/2026-07-15-21-45-33.gh-issue-141276.xH7qP2.rst
b/Misc/NEWS.d/next/Library/2026-07-15-21-45-33.gh-issue-141276.xH7qP2.rst
new file mode 100644
index 000000000000000..c19c7bbd31eb488
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-07-15-21-45-33.gh-issue-141276.xH7qP2.rst
@@ -0,0 +1,6 @@
+Fix duplicate :exc:`SyntaxWarning` messages when importing source modules
+from ZIP archives. :meth:`zipimport.zipimporter.get_filename`, and therefore
+:meth:`~zipimport.zipimporter.find_spec`, no longer compile source modules. A
+:exc:`SyntaxError` in a zipped source module is now raised when the module is
+executed rather than when it is found, matching the behavior of
+filesystem-based loaders.
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