Improve Python 2 only syntax detection (GH-2592)

[etc/vim.git] / src / black / __init__.py

diff --git a/src/black/__init__.py b/src/black/__init__.py
index c503c1a55f78d9be7088c571572334d9f7cd837e..ad4ee1a0d1a6dff08825d6580f9d9cf94793c0ff 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -1061,6 +1061,15 @@ def format_str(src_contents: str, *, mode: Mode) -> FileContent:
         versions = mode.target_versions
     else:
         versions = detect_target_versions(src_node)
+
+    # TODO: fully drop support and this code hopefully in January 2022 :D
+    if TargetVersion.PY27 in mode.target_versions or versions == {TargetVersion.PY27}:
+        msg = (
+            "DEPRECATION: Python 2 support will be removed in the first stable release "
+            "expected in January 2022."
+        )
+        err(msg, fg="yellow", bold=True)
+
     normalize_fmt_off(src_node)
     lines = LineGenerator(
         mode=mode,
@@ -1103,7 +1112,7 @@ def decode_bytes(src: bytes) -> Tuple[FileContent, Encoding, NewLine]:
         return tiow.read(), encoding, newline
 
 
-def get_features_used(node: Node) -> Set[Feature]:
+def get_features_used(node: Node) -> Set[Feature]:  # noqa: C901
     """Return a set of (relatively) new Python features used in this file.
 
     Currently looking for:
@@ -1113,6 +1122,7 @@ def get_features_used(node: Node) -> Set[Feature]:
     - positional only arguments in function signatures and lambdas;
     - assignment expression;
     - relaxed decorator syntax;
+    - print / exec statements;
     """
     features: Set[Feature] = set()
     for n in node.pre_order():
@@ -1122,8 +1132,17 @@ def get_features_used(node: Node) -> Set[Feature]:
                 features.add(Feature.F_STRINGS)
 
         elif n.type == token.NUMBER:
-            if "_" in n.value:  # type: ignore
+            assert isinstance(n, Leaf)
+            if "_" in n.value:
                 features.add(Feature.NUMERIC_UNDERSCORES)
+            elif n.value.endswith(("L", "l")):
+                # Python 2: 10L
+                features.add(Feature.LONG_INT_LITERAL)
+            elif len(n.value) >= 2 and n.value[0] == "0" and n.value[1].isdigit():
+                # Python 2: 0123; 00123; ...
+                if not all(char == "0" for char in n.value):
+                    # although we don't want to match 0000 or similar
+                    features.add(Feature.OCTAL_INT_LITERAL)
 
         elif n.type == token.SLASH:
             if n.parent and n.parent.type in {
@@ -1161,6 +1180,32 @@ def get_features_used(node: Node) -> Set[Feature]:
                         if argch.type in STARS:
                             features.add(feature)
 
+        # Python 2 only features (for its deprecation) except for integers, see above
+        elif n.type == syms.print_stmt:
+            features.add(Feature.PRINT_STMT)
+        elif n.type == syms.exec_stmt:
+            features.add(Feature.EXEC_STMT)
+        elif n.type == syms.tfpdef:
+            # def set_position((x, y), value):
+            #     ...
+            features.add(Feature.AUTOMATIC_PARAMETER_UNPACKING)
+        elif n.type == syms.except_clause:
+            # try:
+            #     ...
+            # except Exception, err:
+            #     ...
+            if len(n.children) >= 4:
+                if n.children[-2].type == token.COMMA:
+                    features.add(Feature.COMMA_STYLE_EXCEPT)
+        elif n.type == syms.raise_stmt:
+            # raise Exception, "msg"
+            if len(n.children) >= 4:
+                if n.children[-2].type == token.COMMA:
+                    features.add(Feature.COMMA_STYLE_RAISE)
+        elif n.type == token.BACKQUOTE:
+            # `i'm surprised this ever existed`
+            features.add(Feature.BACKQUOTE_REPR)
+
     return features