[pull] main from python:main

Doc/conf.py

@@ -557,6 +557,7 @@
 # mapping unique short aliases to a base URL and a prefix.
 # https://www.sphinx-doc.org/en/master/usage/extensions/extlinks.html
 extlinks = {
+    "oss-fuzz": ("https://issues.oss-fuzz.com/issues/%s", "#%s"),
     "pypi": ("https://pypi.org/project/%s/", "%s"),
     "source": (SOURCE_URI, "%s"),
 }

Doc/installing/index.rst

@@ -6,8 +6,6 @@
 Installing Python Modules
 *************************
 
-:Email: distutils-sig@python.org
-
 As a popular open source development project, Python has an active
 supporting community of contributors and users that also make their software
 available for other Python developers to use under open source license terms.

Lib/_ast_unparse.py

@@ -738,9 +738,13 @@ def visit_SetComp(self, node):
 
     def visit_DictComp(self, node):
         with self.delimit("{", "}"):
-            self.traverse(node.key)
-            self.write(": ")
-            self.traverse(node.value)
+            if node.value:
+                self.traverse(node.key)
+                self.write(": ")
+                self.traverse(node.value)
+            else:
+                self.write("**")
+                self.traverse(node.key)
             for gen in node.generators:
                 self.traverse(gen)
 

Lib/test/test_future_stmt/test_future.py

@@ -349,6 +349,8 @@ def test_annotations(self):
         eq("(i ** 2 + j for i in (1, 2, 3) for j in (1, 2, 3))")
         eq("{i: 0 for i in (1, 2, 3)}")
         eq("{i: j for i, j in ((1, 'a'), (2, 'b'), (3, 'c'))}")
+        eq("{**x for x in ()}")
+        eq("[*x for x in ()]")
         eq("[(x, y) for x, y in (a, b)]")
         eq("[(x,) for x, in (a,)]")
         eq("Python3 > Python2 > COBOL")

Lib/test/test_listcomps.py

@@ -180,6 +180,18 @@ def test_references___class___defined(self):
                 code, outputs={"res": [2]}, scopes=["module", "function"])
         self._check_in_scopes(code, raises=NameError, scopes=["class"])
 
+    def test_references___classdict__(self):
+        code = """
+            class i: [__classdict__ for x in y]
+        """
+        self._check_in_scopes(code, raises=NameError)
+
+    def test_references___conditional_annotations__(self):
+        code = """
+            class i: [__conditional_annotations__ for x in y]
+        """
+        self._check_in_scopes(code, raises=NameError)
+
     def test_references___class___enclosing(self):
         code = """
             __class__ = 2

Lib/test/test_unparse.py

@@ -403,6 +403,11 @@ def test_set_comprehension(self):
     def test_dict_comprehension(self):
         self.check_ast_roundtrip("{x: x*x for x in range(10)}")
 
+    def test_dict_comprehension_unpacking(self):
+        self.check_ast_roundtrip("{**x for x in ()}")
+        self.check_ast_roundtrip("{**x for x in range(10)}")
+        self.check_ast_roundtrip("[*x for x in ()]")
+
     def test_class_decorators(self):
         self.check_ast_roundtrip(class_decorator)
 

Makefile.pre.in

@@ -1729,9 +1729,6 @@ FROZEN_FILES_IN = \
 		Lib/zipimport.py \
 		Lib/abc.py \
 		Lib/codecs.py \
-		Lib/encodings/__init__.py \
-		Lib/encodings/aliases.py \
-		Lib/encodings/utf_8.py \
 		Lib/io.py \
 		Lib/_collections_abc.py \
 		Lib/_sitebuiltins.py \
@@ -1741,7 +1738,6 @@ FROZEN_FILES_IN = \
 		Lib/os.py \
 		Lib/site.py \
 		Lib/stat.py \
-		Lib/linecache.py \
 		Lib/importlib/util.py \
 		Lib/importlib/machinery.py \
 		Lib/runpy.py \
@@ -1758,9 +1754,6 @@ FROZEN_FILES_OUT = \
 		Python/frozen_modules/zipimport.h \
 		Python/frozen_modules/abc.h \
 		Python/frozen_modules/codecs.h \
-		Python/frozen_modules/encodings.h \
-		Python/frozen_modules/encodings.aliases.h \
-		Python/frozen_modules/encodings.utf_8.h \
 		Python/frozen_modules/io.h \
 		Python/frozen_modules/_collections_abc.h \
 		Python/frozen_modules/_sitebuiltins.h \
@@ -1770,7 +1763,6 @@ FROZEN_FILES_OUT = \
 		Python/frozen_modules/os.h \
 		Python/frozen_modules/site.h \
 		Python/frozen_modules/stat.h \
-		Python/frozen_modules/linecache.h \
 		Python/frozen_modules/importlib.util.h \
 		Python/frozen_modules/importlib.machinery.h \
 		Python/frozen_modules/runpy.h \
@@ -1810,15 +1802,6 @@ Python/frozen_modules/abc.h: Lib/abc.py $(FREEZE_MODULE_DEPS)
 Python/frozen_modules/codecs.h: Lib/codecs.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) codecs $(srcdir)/Lib/codecs.py Python/frozen_modules/codecs.h
 
-Python/frozen_modules/encodings.h: Lib/encodings/__init__.py $(FREEZE_MODULE_DEPS)
-	$(FREEZE_MODULE) encodings $(srcdir)/Lib/encodings/__init__.py Python/frozen_modules/encodings.h
-
-Python/frozen_modules/encodings.aliases.h: Lib/encodings/aliases.py $(FREEZE_MODULE_DEPS)
-	$(FREEZE_MODULE) encodings.aliases $(srcdir)/Lib/encodings/aliases.py Python/frozen_modules/encodings.aliases.h
-
-Python/frozen_modules/encodings.utf_8.h: Lib/encodings/utf_8.py $(FREEZE_MODULE_DEPS)
-	$(FREEZE_MODULE) encodings.utf_8 $(srcdir)/Lib/encodings/utf_8.py Python/frozen_modules/encodings.utf_8.h
-
 Python/frozen_modules/io.h: Lib/io.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) io $(srcdir)/Lib/io.py Python/frozen_modules/io.h
 
@@ -1846,9 +1829,6 @@ Python/frozen_modules/site.h: Lib/site.py $(FREEZE_MODULE_DEPS)
 Python/frozen_modules/stat.h: Lib/stat.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) stat $(srcdir)/Lib/stat.py Python/frozen_modules/stat.h
 
-Python/frozen_modules/linecache.h: Lib/linecache.py $(FREEZE_MODULE_DEPS)
-	$(FREEZE_MODULE) linecache $(srcdir)/Lib/linecache.py Python/frozen_modules/linecache.h
-
 Python/frozen_modules/importlib.util.h: Lib/importlib/util.py $(FREEZE_MODULE_DEPS)
 	$(FREEZE_MODULE) importlib.util $(srcdir)/Lib/importlib/util.py Python/frozen_modules/importlib.util.h
 

Misc/NEWS.d/next/Core_and_Builtins/2026-03-05-16-16-17.gh-issue-143055.qDUFlY.rst

@@ -0,0 +1,2 @@
+Fix crash in AST unparser when unparsing dict comprehension unpacking.
+Found by OSS Fuzz in :oss-fuzz:`489790200`.

Misc/NEWS.d/next/Core_and_Builtins/2026-03-09-18-52-03.gh-issue-145701.79KQyO.rst

@@ -0,0 +1,3 @@
+Fix :exc:`SystemError` when ``__classdict__`` or
+``__conditional_annotations__`` is in a class-scope inlined comprehension.
+Found by OSS Fuzz in :oss-fuzz:`491105000`.

Modules/_xxtestfuzz/fuzzer.c

@@ -517,8 +517,8 @@ static int fuzz_pycompile(const char* data, size_t size) {
         return 0;
     }
 
-    // Need 2 bytes for parameter selection
-    if (size < 2) {
+    // Need 3 bytes for parameter selection
+    if (size < 3) {
         return 0;
     }
 
@@ -530,25 +530,39 @@ static int fuzz_pycompile(const char* data, size_t size) {
     unsigned char optimize_idx = (unsigned char) data[1];
     int optimize = optimize_vals[optimize_idx % NUM_OPTIMIZE_VALS];
 
+    // Use third byte to determine compiler flags to use.
+    unsigned char flags_byte = (unsigned char) data[2];
+    PyCompilerFlags flags = _PyCompilerFlags_INIT;
+    if (flags_byte & 0x01) {
+        flags.cf_flags |= PyCF_DONT_IMPLY_DEDENT;
+    }
+    if (flags_byte & 0x02) {
+        flags.cf_flags |= PyCF_ONLY_AST;
+    }
+    if (flags_byte & 0x04) {
+        flags.cf_flags |= PyCF_IGNORE_COOKIE;
+    }
+    if (flags_byte & 0x08) {
+        flags.cf_flags |= PyCF_TYPE_COMMENTS;
+    }
+    if (flags_byte & 0x10) {
+        flags.cf_flags |= PyCF_ALLOW_TOP_LEVEL_AWAIT;
+    }
+    if (flags_byte & 0x20) {
+        flags.cf_flags |= PyCF_ALLOW_INCOMPLETE_INPUT;
+    }
+    if (flags_byte & 0x40) {
+        flags.cf_flags |= PyCF_OPTIMIZED_AST;
+    }
+
     char pycompile_scratch[MAX_PYCOMPILE_TEST_SIZE];
 
     // Create a NUL-terminated C string from the remaining input
-    memcpy(pycompile_scratch, data + 2, size - 2);
+    memcpy(pycompile_scratch, data + 3, size - 3);
     // Put a NUL terminator just after the copied data. (Space was reserved already.)
-    pycompile_scratch[size - 2] = '\0';
-
-    // XXX: instead of always using NULL for the `flags` value to
-    // `Py_CompileStringExFlags`, there are many flags that conditionally
-    // change parser behavior:
-    //
-    //     #define PyCF_TYPE_COMMENTS 0x1000
-    //     #define PyCF_ALLOW_TOP_LEVEL_AWAIT 0x2000
-    //     #define PyCF_ONLY_AST 0x0400
-    //
-    // It would be good to test various combinations of these, too.
-    PyCompilerFlags *flags = NULL;
-
-    PyObject *result = Py_CompileStringExFlags(pycompile_scratch, "<fuzz input>", start, flags, optimize);
+    pycompile_scratch[size - 3] = '\0';
+
+    PyObject *result = Py_CompileStringExFlags(pycompile_scratch, "<fuzz input>", start, &flags, optimize);
     if (result == NULL) {
         /* Compilation failed, most likely from a syntax error. If it was a
            SystemError we abort. There's no non-bug reason to raise a

Modules/getpath.py

@@ -776,9 +776,9 @@ def search_up(prefix, *landmarks, test=isfile):
 # Warn if the standard library is missing, unless pythonpath_was_set was set, as
 # that skips parts of the stdlib directories calculation — assume the provided
 # pythonpath is correct. This is how subinterpreters initialize the path for eg.
-if not py_setpath and not pythonpath_was_set and (not stdlib_zip or not isfile(stdlib_zip)):
+if not py_setpath and not pythonpath_was_set:
     home_hint = f"The Python 'home' directory was set to {home!r}, is this correct?"
-    if not stdlib_dir or not isdir(stdlib_dir):
+    if (not stdlib_zip or not isfile(stdlib_zip)) and (not stdlib_dir or not isdir(stdlib_dir)):
         hint = home_hint if home else f'sys.prefix is set to {prefix}, is this correct?'
         warn('WARN: Could not find the standard library directory! ' + hint)
     elif not platstdlib_dir or not isdir(platstdlib_dir):

Objects/typeobject.c

@@ -647,7 +647,6 @@ clear_tp_bases(PyTypeObject *self, int final)
 static inline PyObject *
 lookup_tp_mro(PyTypeObject *self)
 {
-    ASSERT_NEW_TYPE_OR_LOCKED(self);
     return self->tp_mro;
 }
 
@@ -664,8 +663,19 @@ set_tp_mro(PyTypeObject *self, PyObject *mro, int initial)
             /* Other checks are done via set_tp_bases. */
             _Py_SetImmortal(mro);
         }
+        else {
+            PyUnstable_Object_EnableDeferredRefcount(mro);
+        }
+    }
+    if (!initial) {
+        type_lock_prevent_release();
+        types_stop_world();
     }
     self->tp_mro = mro;
+    if (!initial) {
+        types_start_world();
+        type_lock_allow_release();
+    }
 }
 
 static inline void
@@ -1728,18 +1738,11 @@ static PyObject *
 type_get_mro(PyObject *tp, void *Py_UNUSED(closure))
 {
     PyTypeObject *type = PyTypeObject_CAST(tp);
-    PyObject *mro;
-
-    BEGIN_TYPE_LOCK();
-    mro = lookup_tp_mro(type);
+    PyObject *mro = lookup_tp_mro(type);
     if (mro == NULL) {
-        mro = Py_None;
-    } else {
-        Py_INCREF(mro);
+        Py_RETURN_NONE;
     }
-
-    END_TYPE_LOCK();
-    return mro;
+    return Py_NewRef(mro);
 }
 
 static PyTypeObject *find_best_base(PyObject *);

PCbuild/_freeze_module.vcxproj

@@ -310,21 +310,6 @@
       <IntFile>$(IntDir)codecs.g.h</IntFile>
       <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\codecs.h</OutFile>
     </None>
-    <None Include="..\Lib\encodings\__init__.py">
-      <ModName>encodings</ModName>
-      <IntFile>$(IntDir)encodings.g.h</IntFile>
-      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.h</OutFile>
-    </None>
-    <None Include="..\Lib\encodings\aliases.py">
-      <ModName>encodings.aliases</ModName>
-      <IntFile>$(IntDir)encodings.aliases.g.h</IntFile>
-      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.aliases.h</OutFile>
-    </None>
-    <None Include="..\Lib\encodings\utf_8.py">
-      <ModName>encodings.utf_8</ModName>
-      <IntFile>$(IntDir)encodings.utf_8.g.h</IntFile>
-      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\encodings.utf_8.h</OutFile>
-    </None>
     <None Include="..\Lib\io.py">
       <ModName>io</ModName>
       <IntFile>$(IntDir)io.g.h</IntFile>
@@ -370,11 +355,6 @@
       <IntFile>$(IntDir)stat.g.h</IntFile>
       <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\stat.h</OutFile>
     </None>
-    <None Include="..\Lib\linecache.py">
-      <ModName>linecache</ModName>
-      <IntFile>$(IntDir)linecache.g.h</IntFile>
-      <OutFile>$(GeneratedFrozenModulesDir)Python\frozen_modules\linecache.h</OutFile>
-    </None>
     <None Include="..\Lib\importlib\util.py">
       <ModName>importlib.util</ModName>
       <IntFile>$(IntDir)importlib.util.g.h</IntFile>

PCbuild/_freeze_module.vcxproj.filters

@@ -537,15 +537,6 @@
     <None Include="..\Lib\codecs.py">
       <Filter>Python Files</Filter>
     </None>
-    <None Include="..\Lib\encodings\__init__.py">
-      <Filter>Python Files</Filter>
-    </None>
-    <None Include="..\Lib\encodings\aliases.py">
-      <Filter>Python Files</Filter>
-    </None>
-    <None Include="..\Lib\encodings\utf_8.py">
-      <Filter>Python Files</Filter>
-    </None>
     <None Include="..\Lib\io.py">
       <Filter>Python Files</Filter>
     </None>
@@ -573,9 +564,6 @@
     <None Include="..\Lib\stat.py">
       <Filter>Python Files</Filter>
     </None>
-    <None Include="..\Lib\linecache.py">
-      <Filter>Python Files</Filter>
-    </None>
     <None Include="..\Lib\importlib\util.py">
       <Filter>Python Files</Filter>
     </None>

Python/ast_unparse.c

@@ -464,9 +464,15 @@ static int
 append_ast_dictcomp(PyUnicodeWriter *writer, expr_ty e)
 {
     APPEND_CHAR('{');
-    APPEND_EXPR(e->v.DictComp.key, PR_TEST);
-    APPEND_STR(": ");
-    APPEND_EXPR(e->v.DictComp.value, PR_TEST);
+    if (e->v.DictComp.value) {
+        APPEND_EXPR(e->v.DictComp.key, PR_TEST);
+        APPEND_STR(": ");
+        APPEND_EXPR(e->v.DictComp.value, PR_TEST);
+    }
+    else {
+        APPEND_STR("**");
+        APPEND_EXPR(e->v.DictComp.key, PR_TEST);
+    }
     APPEND(comprehensions, e->v.DictComp.generators);
     APPEND_CHAR_FINISH('}');
 }

Python/frozen.c

@@ -46,9 +46,6 @@
 #include "frozen_modules/zipimport.h"
 #include "frozen_modules/abc.h"
 #include "frozen_modules/codecs.h"
-#include "frozen_modules/encodings.h"
-#include "frozen_modules/encodings.aliases.h"
-#include "frozen_modules/encodings.utf_8.h"
 #include "frozen_modules/io.h"
 #include "frozen_modules/_collections_abc.h"
 #include "frozen_modules/_sitebuiltins.h"
@@ -58,7 +55,6 @@
 #include "frozen_modules/os.h"
 #include "frozen_modules/site.h"
 #include "frozen_modules/stat.h"
-#include "frozen_modules/linecache.h"
 #include "frozen_modules/importlib.util.h"
 #include "frozen_modules/importlib.machinery.h"
 #include "frozen_modules/runpy.h"
@@ -80,9 +76,6 @@ static const struct _frozen stdlib_modules[] = {
     /* stdlib - startup, without site (python -S) */
     {"abc", _Py_M__abc, (int)sizeof(_Py_M__abc), false},
     {"codecs", _Py_M__codecs, (int)sizeof(_Py_M__codecs), false},
-    {"encodings", _Py_M__encodings, (int)sizeof(_Py_M__encodings), true},
-    {"encodings.aliases", _Py_M__encodings_aliases, (int)sizeof(_Py_M__encodings_aliases), false},
-    {"encodings.utf_8", _Py_M__encodings_utf_8, (int)sizeof(_Py_M__encodings_utf_8), false},
     {"io", _Py_M__io, (int)sizeof(_Py_M__io), false},
 
     /* stdlib - startup, with site */
@@ -95,9 +88,6 @@ static const struct _frozen stdlib_modules[] = {
     {"site", _Py_M__site, (int)sizeof(_Py_M__site), false},
     {"stat", _Py_M__stat, (int)sizeof(_Py_M__stat), false},
 
-    /* pythonrun - interactive */
-    {"linecache", _Py_M__linecache, (int)sizeof(_Py_M__linecache), false},
-
     /* runpy - run module with -m */
     {"importlib.util", _Py_M__importlib_util, (int)sizeof(_Py_M__importlib_util), false},
     {"importlib.machinery", _Py_M__importlib_machinery, (int)sizeof(_Py_M__importlib_machinery), false},