Fix string normalization sometimes producing invalid fstrings (#327)

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index 1d2f1a304ee768bac626d50e8fef60721e868b34..35daaa9d634fa0d0a278014df7277ef56d1af1fc 100644 (file)
--- a/black.py
+++ b/black.py
@@ -47,7 +47,7 @@ from blib2to3.pgen2 import driver, token
 from blib2to3.pgen2.parse import ParseError
 
 
-__version__ = "18.6b1"
+__version__ = "18.6b2"
 DEFAULT_LINE_LENGTH = 88
 DEFAULT_EXCLUDES = (
     r"/(\.git|\.hg|\.mypy_cache|\.tox|\.venv|_build|buck-out|build|dist)/"
@@ -191,7 +191,7 @@ def read_pyproject_toml(
     return value
 
 
-@click.command()
+@click.command(context_settings=dict(help_option_names=["-h", "--help"]))
 @click.option(
     "-l",
     "--line-length",
@@ -1230,6 +1230,9 @@ class Line:
 
         Provide a non-negative leaf `_index` to speed up the function.
         """
+        if not self.comments:
+            return
+
         if _index == -1:
             for _index, _leaf in enumerate(self.leaves):
                 if leaf is _leaf:
@@ -2546,6 +2549,12 @@ def normalize_string_quotes(leaf: Leaf) -> None:
             leaf.value = f"{prefix}{orig_quote}{body}{orig_quote}"
         new_body = sub_twice(escaped_orig_quote, rf"\1\2{orig_quote}", new_body)
         new_body = sub_twice(unescaped_new_quote, rf"\1\\{new_quote}", new_body)
+    if "f" in prefix.casefold():
+        matches = re.findall(r"[^{]\{(.*?)\}[^}]", new_body)
+        for m in matches:
+            if "\\" in str(m):
+                # Do not introduce backslashes in interpolated expressions
+                return
     if new_quote == '"""' and new_body[-1:] == '"':
         # edge case:
         new_body = new_body[:-1] + '\\"'