Match 3.7's handling of doc strings on functions

DinoV · DinoV · commit 94fd08ac2c20 · 2021-01-28T11:14:38.000-08:00
Summary: Python 3.7 no longer skips doc strings for functions.  They still won't actually be emitted due to just being constants expr's which get optimized away.  But they do impact the line number information for debugging purposes.

Test Plan: ./python -m test.test_compiler
diff --git a/compiler/pycodegen.py b/compiler/pycodegen.py
@@ -358,6 +358,8 @@ def processBody(self, body, gen):
     def _visitAnnotation(self, node):
         return self.visit(node)
 
+    skip_func_docstring = skip_docstring
+
     def _visitFuncOrLambda(self, node, isLambda=0):
         if not isLambda and node.decorator_list:
             for decorator in node.decorator_list:
@@ -370,7 +372,7 @@ def _visitFuncOrLambda(self, node, isLambda=0):
                                self.class_name, self.module)
         body = node.body
         if not isLambda:
-            body = self.skip_docstring(body)
+            body = self.skip_func_docstring(body)
 
         self.processBody(body, gen)
 
@@ -2115,6 +2117,9 @@ def visitTryFinally(self, node, except_protect=False):
             self.emit('POP_EXCEPT')
         self.setups.pop()
 
+    def skip_func_docstring(self, body):
+        return body
+
     def emitMapUnpack(self, containers, is_unpacking):
         if containers > 1 or is_unpacking:
             self.emit('BUILD_MAP_UNPACK', containers)
diff --git a/test_compiler/test_py37.py b/test_compiler/test_py37.py
@@ -99,6 +99,21 @@ def test_try_except_pop_except(self):
                     self.assertEqual(prev_instr.opname == "END_FINALLY", generator is Python37CodeGenerator, prev_instr.opname)
                 prev_instr = instr
 
+    def test_func_doc_str(self):
+        """POP_EXCEPT moved after END_FINALLY in Python 3.7"""
+        test_code = """
+            def f():
+
+                '''hello there
+
+                '''
+            """
+
+        py37_code = self.find_code(self.compile(test_code, Python37CodeGenerator))
+        self.assertEqual(py37_code.co_lnotab, b"\x00\x04")
+
+        py36_code = self.find_code(self.compile(test_code, CodeGenerator))
+        self.assertEqual(py36_code.co_lnotab, b"")
 
     def test_future_annotations(self):
         annotations = ["42"]
