implement simonpercivall#20 and simonpercivall#19

Author: simmsb

lib/astunparse/unparser.py

@@ -64,7 +64,8 @@ def dispatch(self, tree, from_statement=False):
             for t in tree:
                 self.dispatch(t)
             return
-        tree.from_statement = from_statement
+        if tree is not None:
+            tree.from_statement = from_statement
         meth = getattr(self, "_" + tree.__class__.__name__)
         meth(tree)
 
@@ -460,7 +461,7 @@ def _Str(self, tree):
 
     format_conversions = {97: 'a', 114: 'r', 115: 's'}
 
-    def _FormattedValue(self, t):
+    def _generic_FormattedValue(self, t):
         # FormattedValue(expr value, int? conversion, expr? format_spec)
         self.write("{")
         self.dispatch(t.value)
@@ -472,16 +473,30 @@ def _FormattedValue(self, t):
             self.write(":")
             if isinstance(t.format_spec, ast.Str):
                 self.write(t.format_spec.s)
+            elif isinstance(t.format_spec, ast.JoinedStr):
+                # 3.6.1+ joined string
+                for value in t.format_spec.values:
+                    if isinstance(value, ast.Str):
+                        self.write(value.s)
+                    else:
+                        self.dispatch(value)
             else:
                 self.dispatch(t.format_spec)
         self.write("}")
 
+    def _FormattedValue(self, t):
+        self.write("f'''")
+        self._generic_FormattedValue(t)
+        self.write("'''")
+
     def _JoinedStr(self, t):
         # JoinedStr(expr* values)
         self.write("f'''")
         for value in t.values:
             if isinstance(value, ast.Str):
                 self.write(value.s)
+            elif isinstance(value, ast.FormattedValue):
+                self._generic_FormattedValue(value)
             else:
                 self.dispatch(value)
         self.write("'''")
@@ -578,9 +593,13 @@ def _Dict(self, t):
 
         def write_pair(pair):
             (k, v) = pair
-            self.dispatch(k)
-            self.write(": ")
-            self.dispatch(v)
+            if k is None:
+                self.write("**")
+                self.dispatch(v)
+            else:
+                self.dispatch(k)
+                self.write(": ")
+                self.dispatch(v)
             self.write(",")
         self._indent += 1
         self.fill("")

tests/common.py

@@ -12,6 +12,7 @@
 else:
     from lib2to3.pgen2 import tokenize
 
+
 def read_pyfile(filename):
     """Read and return the contents of a Python source file (as a
     string), taking into account the file encoding."""
@@ -25,6 +26,7 @@ def read_pyfile(filename):
             source = pyfile.read()
     return source
 
+
 code_parseable_in_all_parser_modes = """\
 (a + b + c) * (d + e + f)
 """
@@ -162,6 +164,7 @@ async def f():
         suite1
 """
 
+
 class AstunparseCommonTestCase:
     # Tests for specific bugs found in earlier versions of unparse
 
@@ -222,7 +225,7 @@ def test_huge_float(self):
 
     @unittest.skipUnless(six.PY2, "Only works for Python 2")
     def test_min_int27(self):
-        self.check_roundtrip(str(-sys.maxint-1))
+        self.check_roundtrip(str(-sys.maxint - 1))
         self.check_roundtrip("-(%s)" % (sys.maxint + 1))
 
     @unittest.skipUnless(six.PY3, "Only works for Python 3")
@@ -288,6 +291,18 @@ def test_raise_from(self):
     def test_bytes(self):
         self.check_roundtrip("b'123'")
 
+    @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
+    def test_formatted_value(self):
+        self.check_roundtrip('f"{value}"')
+        self.check_roundtrip('f"{value!s}"')
+        self.check_roundtrip('f"{value:4}"')
+        self.check_roundtrip('f"{value!s:4}"')
+
+    @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
+    def test_dict_with_unpacking(self):
+        self.check_roundtrip("{**x}")
+        self.check_roundtrip("{a: b, **x}")
+
     @unittest.skipIf(sys.version_info < (3, 6), "Not supported < 3.6")
     def test_joined_str(self):
         self.check_roundtrip('f"{key}={value!s}"')