python · carljm · Jan 30, 2023 · Jan 31, 2023 · Jan 31, 2023 · Jan 31, 2023
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
@@ -1210,6 +1210,14 @@ iterations of the loop.
 
    .. versionadded:: 3.12
 
+.. opcode:: LOAD_FAST_AND_CLEAR (var_num)
+
+   Pushes a reference to the local ``co_varnames[var_num]`` onto the stack (or
+   pushes ``NULL`` onto the stack if the local variable has not been
+   initialized) and sets ``co_varnames[var_num]`` to ``NULL``.
+
+   .. versionadded:: 3.12
+
 .. opcode:: STORE_FAST (var_num)
 
    Stores ``STACK.pop()`` into the local ``co_varnames[var_num]``.

diff --git a/Include/internal/pycore_code.h b/Include/internal/pycore_code.h
@@ -125,6 +125,7 @@ struct callable_cache {
 // Note that these all fit within a byte, as do combinations.
 // Later, we will use the smaller numbers to differentiate the different
 // kinds of locals (e.g. pos-only arg, varkwargs, local-only).
+#define CO_FAST_HIDDEN  0x10
 #define CO_FAST_LOCAL   0x20
 #define CO_FAST_CELL    0x40
 #define CO_FAST_FREE    0x80

diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
diff --git a/Include/internal/pycore_symtable.h b/Include/internal/pycore_symtable.h
@@ -64,6 +64,7 @@ typedef struct _symtable_entry {
     unsigned ste_needs_class_closure : 1; /* for class scopes, true if a
                                              closure over __class__
                                              should be created */
+    unsigned ste_comp_inlined : 1; /* true if this comprehension is inlined */
     unsigned ste_comp_iter_target : 1; /* true if visiting comprehension target */
     int ste_comp_iter_expr; /* non-zero if visiting a comprehension range expression */
     int ste_lineno;          /* first line of block */

diff --git a/Include/opcode.h b/Include/opcode.h
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
@@ -435,6 +435,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.12a6 3519 (Modify SEND instruction)
 #     Python 3.12a6 3520 (Remove PREP_RERAISE_STAR, add CALL_INTRINSIC_2)
 #     Python 3.12a7 3521 (Shrink the LOAD_GLOBAL caches)
+#     Python 3.12a7 3522 (Inline list/dict/set comprehensions)
 
 #     Python 3.13 will start with 3550
 
@@ -451,7 +452,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3521).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3522).to_bytes(2, 'little') + b'\r\n'
 
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 

diff --git a/Lib/opcode.py b/Lib/opcode.py
@@ -197,6 +197,8 @@ def pseudo_op(name, op, real_ops):
 hascompare.append(141)
 
 def_op('CALL_FUNCTION_EX', 142)  # Flags
+def_op('LOAD_FAST_AND_CLEAR', 143)  # Local variable number
+haslocal.append(143)
 
 def_op('EXTENDED_ARG', 144)
 EXTENDED_ARG = 144
@@ -242,6 +244,8 @@ def pseudo_op(name, op, real_ops):
 
 pseudo_op('LOAD_METHOD', 262, ['LOAD_ATTR'])
 
+pseudo_op('STORE_FAST_MAYBE_NULL', 263, ['STORE_FAST'])
+
 MAX_PSEUDO_OPCODE = MIN_PSEUDO_OPCODE + len(_pseudo_ops) - 1
 
 del def_op, name_op, jrel_op, jabs_op, pseudo_op

diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
@@ -1352,14 +1352,11 @@ def test_multiline_list_comprehension(self):
                                and x != 50)]
             """)
         compiled_code, _ = self.check_positions_against_ast(snippet)
-        compiled_code = compiled_code.co_consts[0]
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'LIST_APPEND',
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
-            line=1, end_line=6, column=0, end_column=32, occurrence=1)
 
     def test_multiline_async_list_comprehension(self):
         snippet = textwrap.dedent("""\
@@ -1374,13 +1371,13 @@ async def f():
         compiled_code, _ = self.check_positions_against_ast(snippet)
         g = {}
         eval(compiled_code, g)
-        compiled_code = g['f'].__code__.co_consts[1]
+        compiled_code = g['f'].__code__
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'LIST_APPEND',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_multiline_set_comprehension(self):
@@ -1393,14 +1390,11 @@ def test_multiline_set_comprehension(self):
                                and x != 50)}
             """)
         compiled_code, _ = self.check_positions_against_ast(snippet)
-        compiled_code = compiled_code.co_consts[0]
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'SET_ADD',
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=1, end_line=2, column=1, end_column=8, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
-            line=1, end_line=6, column=0, end_column=32, occurrence=1)
 
     def test_multiline_async_set_comprehension(self):
         snippet = textwrap.dedent("""\
@@ -1415,13 +1409,13 @@ async def f():
         compiled_code, _ = self.check_positions_against_ast(snippet)
         g = {}
         eval(compiled_code, g)
-        compiled_code = g['f'].__code__.co_consts[1]
+        compiled_code = g['f'].__code__
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'SET_ADD',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=12, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_multiline_dict_comprehension(self):
@@ -1434,14 +1428,11 @@ def test_multiline_dict_comprehension(self):
                                and x != 50)}
             """)
         compiled_code, _ = self.check_positions_against_ast(snippet)
-        compiled_code = compiled_code.co_consts[0]
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'MAP_ADD',
             line=1, end_line=2, column=1, end_column=7, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=1, end_line=2, column=1, end_column=7, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
-            line=1, end_line=6, column=0, end_column=32, occurrence=1)
 
     def test_multiline_async_dict_comprehension(self):
         snippet = textwrap.dedent("""\
@@ -1456,13 +1447,13 @@ async def f():
         compiled_code, _ = self.check_positions_against_ast(snippet)
         g = {}
         eval(compiled_code, g)
-        compiled_code = g['f'].__code__.co_consts[1]
+        compiled_code = g['f'].__code__
         self.assertIsInstance(compiled_code, types.CodeType)
         self.assertOpcodeSourcePositionIs(compiled_code, 'MAP_ADD',
             line=2, end_line=3, column=5, end_column=11, occurrence=1)
         self.assertOpcodeSourcePositionIs(compiled_code, 'JUMP_BACKWARD',
             line=2, end_line=3, column=5, end_column=11, occurrence=1)
-        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_VALUE',
+        self.assertOpcodeSourcePositionIs(compiled_code, 'RETURN_CONST',
             line=2, end_line=7, column=4, end_column=36, occurrence=1)
 
     def test_matchcase_sequence(self):
@@ -1711,9 +1702,6 @@ def test_column_offset_deduplication(self):
         for source in [
             "lambda: a",
             "(a for b in c)",
-            "[a for b in c]",
-            "{a for b in c}",
-            "{a: b for c in d}",
         ]:
             with self.subTest(source):
                 code = compile(f"{source}, {source}", "<test>", "eval")

diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
@@ -154,15 +154,15 @@ def bug708901():
 
 
 def bug1333982(x=[]):
-    assert 0, ([s for s in x] +
+    assert 0, ((s for s in x) +
               1)
     pass
 
 dis_bug1333982 = """\
 %3d        RESUME                   0
 
 %3d        LOAD_ASSERTION_ERROR
-           LOAD_CONST               1 (<code object <listcomp> at 0x..., file "%s", line %d>)
+           LOAD_CONST               1 (<code object <genexpr> at 0x..., file "%s", line %d>)
            MAKE_FUNCTION            0
            LOAD_FAST                0 (x)
            GET_ITER
@@ -628,7 +628,7 @@ async def _co(x):
 def _h(y):
     def foo(x):
         '''funcdoc'''
-        return [x + z for z in y]
+        return list(x + z for z in y)
     return foo
 
 dis_nested_0 = """\
@@ -658,13 +658,15 @@ def foo(x):
 
 %3d        RESUME                   0
 
-%3d        LOAD_CLOSURE             0 (x)
+%3d        LOAD_GLOBAL              1 (NULL + list)
+           LOAD_CLOSURE             0 (x)
            BUILD_TUPLE              1
-           LOAD_CONST               1 (<code object <listcomp> at 0x..., file "%s", line %d>)
+           LOAD_CONST               1 (<code object <genexpr> at 0x..., file "%s", line %d>)
            MAKE_FUNCTION            8 (closure)
            LOAD_DEREF               1 (y)
            GET_ITER
            CALL                     0
+           CALL                     1
            RETURN_VALUE
 """ % (dis_nested_0,
        __file__,
@@ -676,21 +678,28 @@ def foo(x):
 )
 
 dis_nested_2 = """%s
-Disassembly of <code object <listcomp> at 0x..., file "%s", line %d>:
+Disassembly of <code object <genexpr> at 0x..., file "%s", line %d>:
            COPY_FREE_VARS           1
 
-%3d        RESUME                   0
-           BUILD_LIST               0
+%3d        RETURN_GENERATOR
+           POP_TOP
+           RESUME                   0
            LOAD_FAST                0 (.0)
-        >> FOR_ITER                 7 (to 26)
+        >> FOR_ITER                 9 (to 32)
            STORE_FAST               1 (z)
            LOAD_DEREF               2 (x)
            LOAD_FAST                1 (z)
            BINARY_OP                0 (+)
-           LIST_APPEND              2
-           JUMP_BACKWARD            9 (to 8)
+           YIELD_VALUE              1
+           RESUME                   1
+           POP_TOP
+           JUMP_BACKWARD           11 (to 10)
         >> END_FOR
-           RETURN_VALUE
+           RETURN_CONST             0 (None)
+        >> CALL_INTRINSIC_1         3
+           RERAISE                  1
+ExceptionTable:
+1 row
 """ % (dis_nested_1,
        __file__,
        _h.__code__.co_firstlineno + 3,

diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
@@ -4215,14 +4215,14 @@ def test(*args, **kwargs):
 
     @cpython_only
     def test_signature_bind_implicit_arg(self):
-        # Issue #19611: getcallargs should work with set comprehensions
+        # Issue #19611: getcallargs should work with comprehensions
         def make_set():
-            return {z * z for z in range(5)}
-        setcomp_code = make_set.__code__.co_consts[1]
-        setcomp_func = types.FunctionType(setcomp_code, {})
+            return set(z * z for z in range(5))
+        gencomp_code = make_set.__code__.co_consts[1]
+        gencomp_func = types.FunctionType(gencomp_code, {})
 
         iterator = iter(range(5))
-        self.assertEqual(self.call(setcomp_func, iterator), {0, 1, 4, 9, 16})
+        self.assertEqual(set(self.call(gencomp_func, iterator)), {0, 1, 4, 9, 16})
 
     def test_signature_bind_posonly_kwargs(self):
         def foo(bar, /, **kwargs):