bpo-40528: Improve and clear several aspects of the ASDL definition code for the AST (GH-19952)

isidentical · web-flow · commit 091951a67c83 · 2020-05-06T15:29:32.000+01:00
diff --git a/Include/asdl.h b/Include/asdl.h
@@ -4,9 +4,7 @@
 
 typedef PyObject * identifier;
 typedef PyObject * string;
-typedef PyObject * bytes;
 typedef PyObject * object;
-typedef PyObject * singleton;
 typedef PyObject * constant;
 
 /* It would be nice if the code generated by asdl_c.py was completely
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
@@ -597,7 +597,7 @@ def test_empty_yield_from(self):
         empty_yield_from.body[0].body[0].value.value = None
         with self.assertRaises(ValueError) as cm:
             compile(empty_yield_from, "<test>", "exec")
-        self.assertIn("field value is required", str(cm.exception))
+        self.assertIn("field 'value' is required", str(cm.exception))
 
     @support.cpython_only
     def test_issue31592(self):
diff --git a/Parser/Python.asdl b/Parser/Python.asdl
@@ -1,5 +1,5 @@
--- ASDL's 5 builtin types are:
--- identifier, int, string, object, constant
+-- ASDL's 4 builtin types are:
+-- identifier, int, string, constant
 
 module Python
 {
diff --git a/Parser/asdl.py b/Parser/asdl.py
@@ -33,8 +33,7 @@
 # See the EBNF at the top of the file to understand the logical connection
 # between the various node types.
 
-builtin_types = {'identifier', 'string', 'bytes', 'int', 'object', 'singleton',
-                 'constant'}
+builtin_types = {'identifier', 'string', 'int', 'constant'}
 
 class AST:
     def __repr__(self):
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
@@ -323,7 +323,7 @@ def emit(s, depth=0, reflow=True):
             if not opt and argtype != "int":
                 emit("if (!%s) {" % argname, 1)
                 emit("PyErr_SetString(PyExc_ValueError,", 2)
-                msg = "field %s is required for %s" % (argname, name)
+                msg = "field '%s' is required for %s" % (argname, name)
                 emit('                "%s");' % msg,
                      2, reflow=False)
                 emit('return NULL;', 2)
@@ -853,11 +853,9 @@ def visitModule(self, mod):
     Py_INCREF((PyObject*)o);
     return (PyObject*)o;
 }
-#define ast2obj_singleton ast2obj_object
 #define ast2obj_constant ast2obj_object
 #define ast2obj_identifier ast2obj_object
 #define ast2obj_string ast2obj_object
-#define ast2obj_bytes ast2obj_object
 
 static PyObject* ast2obj_int(long b)
 {
@@ -1147,12 +1145,8 @@ def simpleSum(self, sum, name):
             self.emit("case %s:" % t.name, 2)
             self.emit("Py_INCREF(astmodulestate_global->%s_singleton);" % t.name, 3)
             self.emit("return astmodulestate_global->%s_singleton;" % t.name, 3)
-        self.emit("default:", 2)
-        self.emit('/* should never happen, but just in case ... */', 3)
-        code = "PyErr_Format(PyExc_SystemError, \"unknown %s found\");" % name
-        self.emit(code, 3, reflow=False)
-        self.emit("return NULL;", 3)
         self.emit("}", 1)
+        self.emit("Py_UNREACHABLE();", 1);
         self.emit("}", 0)
 
     def visitProduct(self, prod, name):
diff --git a/Python/Python-ast.c b/Python/Python-ast.c

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,5 @@`
`1`		`--- ASDL's 5 builtin types are:`
`2`		`--- identifier, int, string, object, constant`
	`1`	`+-- ASDL's 4 builtin types are:`
	`2`	`+-- identifier, int, string, constant`
`3`	`3`
`4`	`4`	`module Python`
`5`	`5`	`{`