Preserve crlf line endings in blackd (#3257)

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

diff --git a/src/blackd/__init__.py b/src/blackd/__init__.py
index a6de79fbeaa4c98300a78442077255d77ba882f0..6bbc7c520866421feefef37befca3e3dd224a11a 100644 (file)
--- a/src/blackd/__init__.py
+++ b/src/blackd/__init__.py
@@ -32,6 +32,7 @@ LINE_LENGTH_HEADER = "X-Line-Length"
 PYTHON_VARIANT_HEADER = "X-Python-Variant"
 SKIP_STRING_NORMALIZATION_HEADER = "X-Skip-String-Normalization"
 SKIP_MAGIC_TRAILING_COMMA = "X-Skip-Magic-Trailing-Comma"
+PREVIEW = "X-Preview"
 FAST_OR_SAFE_HEADER = "X-Fast-Or-Safe"
 DIFF_HEADER = "X-Diff"
 
@@ -41,6 +42,7 @@ BLACK_HEADERS = [
     PYTHON_VARIANT_HEADER,
     SKIP_STRING_NORMALIZATION_HEADER,
     SKIP_MAGIC_TRAILING_COMMA,
+    PREVIEW,
     FAST_OR_SAFE_HEADER,
     DIFF_HEADER,
 ]
@@ -109,6 +111,7 @@ async def handle(request: web.Request, executor: Executor) -> web.Response:
         skip_magic_trailing_comma = bool(
             request.headers.get(SKIP_MAGIC_TRAILING_COMMA, False)
         )
+        preview = bool(request.headers.get(PREVIEW, False))
         fast = False
         if request.headers.get(FAST_OR_SAFE_HEADER, "safe") == "fast":
             fast = True
@@ -118,6 +121,7 @@ async def handle(request: web.Request, executor: Executor) -> web.Response:
             line_length=line_length,
             string_normalization=not skip_string_normalization,
             magic_trailing_comma=not skip_magic_trailing_comma,
+            preview=preview,
         )
         req_bytes = await request.content.read()
         charset = request.charset if request.charset is not None else "utf8"
@@ -129,6 +133,13 @@ async def handle(request: web.Request, executor: Executor) -> web.Response:
             executor, partial(black.format_file_contents, req_str, fast=fast, mode=mode)
         )
 
+        # Preserve CRLF line endings
+        if req_str[req_str.find("\n") - 1] == "\r":
+            formatted_str = formatted_str.replace("\n", "\r\n")
+            # If, after swapping line endings, nothing changed, then say so
+            if formatted_str == req_str:
+                raise black.NothingChanged
+
         # Only output the diff in the HTTP response
         only_diff = bool(request.headers.get(DIFF_HEADER, False))
         if only_diff: