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Merged
serhiy-storchaka merged 3 commits into from
Aug 29, 2017
Merged

bpo-31286: Fixed stack usage in absolute imports with binding a submo… #3217

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97dd426
bpo-31286: Fixed stack usage in absolute imports with binding a submo…
serhiy-storchaka Aug 27, 2017
225ffd1
Add more tests.
serhiy-storchaka Aug 27, 2017
22169d8
Remove the NEWS entry.
serhiy-storchaka Aug 29, 2017
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17 changes: 17 additions & 0 deletions Lib/test/test_import/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,23 @@ def test_import_name_binding(self):
import test.support as y
self.assertIs(y, test.support, y.__name__)

def test_issue31286(self):
# import in a 'finally' block resulted in SystemError
try:
x = ...
finally:
import test.support.script_helper as x

# import in a 'while' loop resulted in stack overflow
i = 0
while i < 10:
import test.support.script_helper as x
i += 1

# import in a 'for' loop resulted in segmentation fault
for i in range(2):
import test.support.script_helper as x

def test_failing_reload(self):
# A failing reload should leave the module object in sys.modules.
source = TESTFN + os.extsep + "py"
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26 changes: 16 additions & 10 deletions Python/compile.c
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Expand Up @@ -2673,28 +2673,34 @@ compiler_import_as(struct compiler *c, identifier name, identifier asname)
If there is a dot in name, we need to split it and emit a
IMPORT_FROM for each name.
*/
Py_ssize_t dot = PyUnicode_FindChar(name, '.', 0,
PyUnicode_GET_LENGTH(name), 1);
Py_ssize_t len = PyUnicode_GET_LENGTH(name);
Py_ssize_t dot = PyUnicode_FindChar(name, '.', 0, len, 1);
if (dot == -2)
return 0;
if (dot != -1) {
/* Consume the base module name to get the first attribute */
Py_ssize_t pos = dot + 1;
while (dot != -1) {
while (1) {
Py_ssize_t pos = dot + 1;
PyObject *attr;
dot = PyUnicode_FindChar(name, '.', pos,
PyUnicode_GET_LENGTH(name), 1);
dot = PyUnicode_FindChar(name, '.', pos, len, 1);
if (dot == -2)
return 0;
attr = PyUnicode_Substring(name, pos,
(dot != -1) ? dot :
PyUnicode_GET_LENGTH(name));
attr = PyUnicode_Substring(name, pos, (dot != -1) ? dot : len);
if (!attr)
return 0;
ADDOP_O(c, IMPORT_FROM, attr, names);
Py_DECREF(attr);
pos = dot + 1;
if (dot == -1) {
break;
}
ADDOP(c, ROT_TWO);
ADDOP(c, POP_TOP);
}
if (!compiler_nameop(c, asname, Store)) {
return 0;
}
ADDOP(c, POP_TOP);
return 1;
}
return compiler_nameop(c, asname, Store);
}
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