Avoid unstable formatting when comment follows escaped newline. (#839). Fixes #767.

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index 7bfcfca874ffd7bcdeae9fed15aa082cf325b549..1978fd52ec91969e226908ebb566d18f422a3ab7 100644 (file)
--- a/black.py
+++ b/black.py
@@ -231,6 +231,7 @@ def read_pyproject_toml(
 
 
 @click.command(context_settings=dict(help_option_names=["-h", "--help"]))
+@click.option("-c", "--code", type=str, help="Format the code passed in as a string.")
 @click.option(
     "-l",
     "--line-length",
@@ -357,6 +358,7 @@ def read_pyproject_toml(
 @click.pass_context
 def main(
     ctx: click.Context,
+    code: Optional[str],
     line_length: int,
     target_version: List[TargetVersion],
     check: bool,
@@ -397,6 +399,9 @@ def main(
     )
     if config and verbose:
         out(f"Using configuration from {config}.", bold=False, fg="blue")
+    if code is not None:
+        print(format_str(code, mode=mode))
+        ctx.exit(0)
     try:
         include_regex = re_compile_maybe_verbose(include)
     except re.error:
@@ -435,22 +440,10 @@ def main(
             report=report,
         )
     else:
-        loop = asyncio.get_event_loop()
-        executor = ProcessPoolExecutor(max_workers=os.cpu_count())
-        try:
-            loop.run_until_complete(
-                schedule_formatting(
-                    sources=sources,
-                    fast=fast,
-                    write_back=write_back,
-                    mode=mode,
-                    report=report,
-                    loop=loop,
-                    executor=executor,
-                )
-            )
-        finally:
-            shutdown(loop)
+        reformat_many(
+            sources=sources, fast=fast, write_back=write_back, mode=mode, report=report
+        )
+
     if verbose or not quiet:
         bang = "💥 💔 💥" if report.return_code else "✨ 🍰 ✨"
         out(f"All done! {bang}")
@@ -492,6 +485,36 @@ def reformat_one(
         report.failed(src, str(exc))
 
 
+def reformat_many(
+    sources: Set[Path],
+    fast: bool,
+    write_back: WriteBack,
+    mode: FileMode,
+    report: "Report",
+) -> None:
+    """Reformat multiple files using a ProcessPoolExecutor."""
+    loop = asyncio.get_event_loop()
+    worker_count = os.cpu_count()
+    if sys.platform == "win32":
+        # Work around https://bugs.python.org/issue26903
+        worker_count = min(worker_count, 61)
+    executor = ProcessPoolExecutor(max_workers=worker_count)
+    try:
+        loop.run_until_complete(
+            schedule_formatting(
+                sources=sources,
+                fast=fast,
+                write_back=write_back,
+                mode=mode,
+                report=report,
+                loop=loop,
+                executor=executor,
+            )
+        )
+    finally:
+        shutdown(loop)
+
+
 async def schedule_formatting(
     sources: Set[Path],
     fast: bool,
@@ -2122,15 +2145,21 @@ def list_comments(prefix: str, *, is_endmarker: bool) -> List[ProtoComment]:
 
     consumed = 0
     nlines = 0
+    ignored_lines = 0
     for index, line in enumerate(prefix.split("\n")):
         consumed += len(line) + 1  # adding the length of the split '\n'
         line = line.lstrip()
         if not line:
             nlines += 1
         if not line.startswith("#"):
+            # Escaped newlines outside of a comment are not really newlines at
+            # all. We treat a single-line comment following an escaped newline
+            # as a simple trailing comment.
+            if line.endswith("\\"):
+                ignored_lines += 1
             continue
 
-        if index == 0 and not is_endmarker:
+        if index == ignored_lines and not is_endmarker:
             comment_type = token.COMMENT  # simple trailing comment
         else:
             comment_type = STANDALONE_COMMENT