Fix handling of empty files

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index 7138d291f13e652df4e15039cf97a06312a05b57..c6b018ffd050431a4592ab5b15820cb610c986f3 100644 (file)
--- a/black.py
+++ b/black.py
@@ -1,6 +1,7 @@
 import asyncio
 from asyncio.base_events import BaseEventLoop
 from concurrent.futures import Executor, ProcessPoolExecutor
+from datetime import datetime
 from enum import Enum, Flag
 from functools import partial, wraps
 import io
@@ -469,6 +470,7 @@ def format_file_in_place(
     if src.suffix == ".pyi":
         mode |= FileMode.PYI
 
+    then = datetime.utcfromtimestamp(src.stat().st_mtime)
     with open(src, "rb") as buf:
         src_contents, encoding, newline = decode_bytes(buf.read())
     try:
@@ -482,8 +484,9 @@ def format_file_in_place(
         with open(src, "w", encoding=encoding, newline=newline) as f:
             f.write(dst_contents)
     elif write_back == write_back.DIFF:
-        src_name = f"{src}  (original)"
-        dst_name = f"{src}  (formatted)"
+        now = datetime.utcnow()
+        src_name = f"{src}\t{then} +0000"
+        dst_name = f"{src}\t{now} +0000"
         diff_contents = diff(src_contents, dst_contents, src_name, dst_name)
         if lock:
             lock.acquire()
@@ -514,6 +517,7 @@ def format_stdin_to_stdout(
     `line_length`, `fast`, `is_pyi`, and `force_py36` arguments are passed to
     :func:`format_file_contents`.
     """
+    then = datetime.utcnow()
     src, encoding, newline = decode_bytes(sys.stdin.buffer.read())
     dst = src
     try:
@@ -530,8 +534,9 @@ def format_stdin_to_stdout(
         if write_back == WriteBack.YES:
             f.write(dst)
         elif write_back == WriteBack.DIFF:
-            src_name = "<stdin>  (original)"
-            dst_name = "<stdin>  (formatted)"
+            now = datetime.utcnow()
+            src_name = f"STDIN\t{then} +0000"
+            dst_name = f"STDOUT\t{now} +0000"
             f.write(diff(src, dst, src_name, dst_name))
         f.detach()
 
@@ -602,6 +607,9 @@ def decode_bytes(src: bytes) -> Tuple[FileContent, Encoding, NewLine]:
     """
     srcbuf = io.BytesIO(src)
     encoding, lines = tokenize.detect_encoding(srcbuf.readline)
+    if not lines:
+        return "", encoding, "\n"
+
     newline = "\r\n" if b"\r\n" == lines[0][-2:] else "\n"
     srcbuf.seek(0)
     with io.TextIOWrapper(srcbuf, encoding) as tiow:
@@ -618,7 +626,7 @@ GRAMMARS = [
 def lib2to3_parse(src_txt: str) -> Node:
     """Given a string with source, return the lib2to3 Node."""
     grammar = pygram.python_grammar_no_print_statement
-    if src_txt[-1] != "\n":
+    if src_txt[-1:] != "\n":
         src_txt += "\n"
     for grammar in GRAMMARS:
         drv = driver.Driver(grammar, pytree.convert)
@@ -763,6 +771,7 @@ UNPACKING_PARENTS = {
     syms.dictsetmaker,
     syms.listmaker,
     syms.testlist_gexp,
+    syms.testlist_star_expr,
 }
 TEST_DESCENDANTS = {
     syms.test,