When trying to write new bytecode, importlib was not catching the IOError

thrown if the file happened to be read-only to keep the failure silent.

Fixes issue #7187. Thanks, Dave Malcolm for the report and analysis of the
problem.

diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
index 466b287c4d2eee1abd38cd5268d439dcdb61109e..02f5c492c5f08779f73ac13de727b8d20ae07cf1 100644 (file)
--- a/Lib/importlib/_bootstrap.py
+++ b/Lib/importlib/_bootstrap.py
@@ -526,9 +526,9 @@ class _PyPycFileLoader(PyPycLoader, _PyFileLoader):
         bytecode_path = self.bytecode_path(name)
         if not bytecode_path:
             bytecode_path = self._base_path + _suffix_list(imp.PY_COMPILED)[0]
-        file = _io.FileIO(bytecode_path, 'w')  # Assuming bytes.
         try:
-            with _closing(file) as bytecode_file:
+            # Assuming bytes.
+            with _closing(_io.FileIO(bytecode_path, 'w')) as bytecode_file:
                 bytecode_file.write(data)
                 return True
         except IOError as exc:

diff --git a/Lib/importlib/test/source/test_file_loader.py b/Lib/importlib/test/source/test_file_loader.py
index b18750c2a38939f570012dcb488e8ba9faf6c4b3..32a6955cc6bedefc92668b821766ddeeef638408 100644 (file)
--- a/Lib/importlib/test/source/test_file_loader.py
+++ b/Lib/importlib/test/source/test_file_loader.py
@@ -6,6 +6,7 @@ from . import util as source_util
 import imp
 import os
 import py_compile
+import stat
 import sys
 import unittest
 
@@ -121,6 +122,10 @@ class BadBytecodeTest(unittest.TestCase):
     But if the marshal data is bad, even if the magic number and timestamp
     work, a ValueError is raised and the source is not used [bad marshal].
 
+    The case of not being able to write out the bytecode must also be handled
+    as it's possible it was made read-only. In that instance the attempt to
+    write the bytecode should fail silently [bytecode read-only].
+
     """
 
     def import_(self, file, module_name):
@@ -159,6 +164,7 @@ class BadBytecodeTest(unittest.TestCase):
                 self.assertEqual(bytecode_file.read(4), source_timestamp)
 
     # [bad marshal]
+    @source_util.writes_bytecode_files
     def test_bad_marshal(self):
         with source_util.create_modules('_temp') as mapping:
             bytecode_path = source_util.bytecode_path(mapping['_temp'])
@@ -172,6 +178,26 @@ class BadBytecodeTest(unittest.TestCase):
                 self.import_(mapping['_temp'], '_temp')
             self.assertTrue('_temp' not in sys.modules)
 
+    # [bytecode read-only]
+    @source_util.writes_bytecode_files
+    def test_read_only_bytecode(self):
+        with source_util.create_modules('_temp') as mapping:
+            # Create bytecode that will need to be re-created.
+            py_compile.compile(mapping['_temp'])
+            bytecode_path = source_util.bytecode_path(mapping['_temp'])
+            with open(bytecode_path, 'r+b') as bytecode_file:
+                bytecode_file.seek(0)
+                bytecode_file.write(b'\x00\x00\x00\x00')
+            # Make the bytecode read-only.
+            os.chmod(bytecode_path,
+                        stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)
+            try:
+                # Should not raise IOError!
+                self.import_(mapping['_temp'], '_temp')
+            finally:
+                # Make writable for eventual clean-up.
+                os.chmod(bytecode_path, stat.S_IWUSR)
+
 
 def test_main():
     from test.support import run_unittest

diff --git a/Misc/ACKS b/Misc/ACKS
index 7ea387b0167f3d468f66383696861ae6cd4a519c..00a4cd7374b28ae1f08cfacaf17931f1e680cebc 100644 (file)
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -472,6 +472,7 @@ Nick Maclaren
 Don MacMillen
 Steve Majewski
 Grzegorz Makarewicz
+Dave Malcolm
 Ken Manheimer
 Vladimir Marangozov
 David Marek

diff --git a/Misc/NEWS b/Misc/NEWS
index 0b98ccbf8e03f0336e9ce0c819a9e25b3e941163..94c16bb900b05cc7917552273aea4919bd5c02c5 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -123,6 +123,9 @@ C-API
 Library
 -------
 
+- Issue #7187: Importlib would not silence the IOError raised when trying to
+  write new bytecode when it was made read-only.
+
 - Issue #7264: Fix a possible deadlock when deallocating thread-local objects
   which are part of a reference cycle.