bpo-41531: Fix compilation of dict literals with more than 0xFFFF elements (GH-21850) (GH-22107)
(cherry picked from commit c51db0ea40ddabaf5f771ea633b37fcf4c90a495)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 566ca27..55716fd 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -750,6 +750,16 @@
self.assertEqual(None, opcodes[0].argval)
self.assertEqual('RETURN_VALUE', opcodes[1].opname)
+ def test_big_dict_literal(self):
+ # The compiler has a flushing point in "compiler_dict" that calls compiles
+ # a portion of the dictionary literal when the loop that iterates over the items
+ # reaches 0xFFFF elements but the code was not including the boundary element,
+ # dropping the key at position 0xFFFF. See bpo-41531 for more information
+
+ dict_size = 0xFFFF + 1
+ the_dict = "{" + ",".join(f"{x}:{x}" for x in range(dict_size)) + "}"
+ self.assertEqual(len(eval(the_dict)), dict_size)
+
class TestExpressionStackSize(unittest.TestCase):
# These tests check that the computed stack size for a code object
# stays within reasonable bounds (see issue #21523 for an example
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-08-12-19-32-15.bpo-41531.WgPzjT.rst b/Misc/NEWS.d/next/Core and Builtins/2020-08-12-19-32-15.bpo-41531.WgPzjT.rst
new file mode 100644
index 0000000..8544664
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-08-12-19-32-15.bpo-41531.WgPzjT.rst
@@ -0,0 +1,2 @@
+Fix a bug that was dropping keys when compiling dict literals with more than
+0xFFFF elements. Patch by Pablo Galindo.
diff --git a/Python/compile.c b/Python/compile.c
index 7ec92e0..51af28b 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -3890,7 +3890,7 @@
}
else {
if (elements == 0xFFFF) {
- if (!compiler_subdict(c, e, i - elements, i)) {
+ if (!compiler_subdict(c, e, i - elements, i + 1)) {
return 0;
}
if (have_dict) {