Remove redundant Python 3.7 code (#17004)

Some follow on from #15566.

Also add 3.12 to tox.ini.

mypy/modulefinder.py

@@ -870,6 +870,6 @@ def parse_version(version: str) -> tuple[int, int]:
 
 def typeshed_py_version(options: Options) -> tuple[int, int]:
     """Return Python version used for checking whether module supports typeshed."""
-    # Typeshed no longer covers Python 3.x versions before 3.7, so 3.7 is
+    # Typeshed no longer covers Python 3.x versions before 3.8, so 3.8 is
     # the earliest we can support.
-    return max(options.python_version, (3, 7))
+    return max(options.python_version, (3, 8))

mypy/stubgenc.py

@@ -495,7 +495,7 @@ def get_type_annotation(self, obj: object) -> str:
         if obj is None or obj is type(None):
             return "None"
         elif inspect.isclass(obj):
-            return "type[{}]".format(self.get_type_fullname(obj))
+            return f"type[{self.get_type_fullname(obj)}]"
         elif isinstance(obj, FunctionType):
             return self.add_name("typing.Callable")
         elif isinstance(obj, ModuleType):

mypy/util.py

@@ -298,7 +298,7 @@ def _generate_junit_contents(
                     text=escape("\n".join(messages)),
                     filename="mypy",
                     time=dt,
-                    name="mypy-py{ver}-{platform}".format(ver=version, platform=platform),
+                    name=f"mypy-py{version}-{platform}",
                 )
 
     xml += JUNIT_FOOTER

mypyc/lib-rt/CPy.h

@@ -544,13 +544,8 @@ void CPy_AttributeError(const char *filename, const char *funcname, const char *
 
 // Misc operations
 
-#if PY_VERSION_HEX >= 0x03080000
 #define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_BEGIN(op, dealloc)
 #define CPy_TRASHCAN_END(op) Py_TRASHCAN_END
-#else
-#define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_SAFE_BEGIN(op)
-#define CPy_TRASHCAN_END(op) Py_TRASHCAN_SAFE_END(op)
-#endif
 
 // Tweaked version of _PyArg_Parser in CPython
 typedef struct CPyArg_Parser {

mypyc/lib-rt/pythonsupport.h

@@ -354,21 +354,6 @@ list_count(PyListObject *self, PyObject *value)
     return CPyTagged_ShortFromSsize_t(count);
 }
 
-#if PY_VERSION_HEX < 0x03080000
-static PyObject *
-_PyDict_GetItemStringWithError(PyObject *v, const char *key)
-{
-    PyObject *kv, *rv;
-    kv = PyUnicode_FromString(key);
-    if (kv == NULL) {
-        return NULL;
-    }
-    rv = PyDict_GetItemWithError(v, kv);
-    Py_DECREF(kv);
-    return rv;
-}
-#endif
-
 #define CPyUnicode_EqualToASCIIString(x, y) _PyUnicode_EqualToASCIIString(x, y)
 
 // Adapted from genobject.c in Python 3.7.2

tox.ini

@@ -6,6 +6,7 @@ envlist =
     py39,
     py310,
     py311,
+    py312,
     docs,
     lint,
     type,