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Improve error messages from BlackRunner
[etc/vim.git] / black.py
index 2a913fc5f2e1ba75ce476cec155e879de75c79c2..3ab4bc76bb23836a1f12bbe4953a5fb6bcbd7b55 100644 (file)
--- a/black.py
+++ b/black.py
@@ -2,7 +2,7 @@ import ast
 import asyncio
 from abc import ABC, abstractmethod
 from collections import defaultdict
-from concurrent.futures import Executor, ProcessPoolExecutor
+from concurrent.futures import Executor, ThreadPoolExecutor, ProcessPoolExecutor
 from contextlib import contextmanager
 from datetime import datetime
 from enum import Enum
@@ -34,6 +34,7 @@ from typing import (
     Pattern,
     Sequence,
     Set,
+    Sized,
     Tuple,
     Type,
     TypeVar,
@@ -353,15 +354,6 @@ def target_version_option_callback(
         " auto-detection]"
     ),
 )
-@click.option(
-    "--py36",
-    is_flag=True,
-    help=(
-        "Allow using Python 3.6-only syntax on all input files.  This will put trailing"
-        " commas in function signatures and calls also after *args and **kwargs."
-        " Deprecated; use --target-version instead. [default: per-file auto-detection]"
-    ),
-)
 @click.option(
     "--pyi",
     is_flag=True,
@@ -424,6 +416,14 @@ def target_version_option_callback(
     ),
     show_default=True,
 )
+@click.option(
+    "--force-exclude",
+    type=str,
+    help=(
+        "Like --exclude, but files and directories matching this regex will be "
+        "excluded even when they are passed explicitly as arguments"
+    ),
+)
 @click.option(
     "-q",
     "--quiet",
@@ -476,29 +476,19 @@ def main(
     color: bool,
     fast: bool,
     pyi: bool,
-    py36: bool,
     skip_string_normalization: bool,
     quiet: bool,
     verbose: bool,
     include: str,
     exclude: str,
+    force_exclude: Optional[str],
     src: Tuple[str, ...],
     config: Optional[str],
 ) -> None:
     """The uncompromising code formatter."""
     write_back = WriteBack.from_configuration(check=check, diff=diff, color=color)
     if target_version:
-        if py36:
-            err("Cannot use both --target-version and --py36")
-            ctx.exit(2)
-        else:
-            versions = set(target_version)
-    elif py36:
-        err(
-            "--py36 is deprecated and will be removed in a future version. Use"
-            " --target-version py36 instead."
-        )
-        versions = PY36_VERSIONS
+        versions = set(target_version)
     else:
         # We'll autodetect later.
         versions = set()
@@ -513,6 +503,57 @@ def main(
     if code is not None:
         print(format_str(code, mode=mode))
         ctx.exit(0)
+    report = Report(check=check, diff=diff, quiet=quiet, verbose=verbose)
+    sources = get_sources(
+        ctx=ctx,
+        src=src,
+        quiet=quiet,
+        verbose=verbose,
+        include=include,
+        exclude=exclude,
+        force_exclude=force_exclude,
+        report=report,
+    )
+
+    path_empty(
+        sources,
+        "No Python files are present to be formatted. Nothing to do 😴",
+        quiet,
+        verbose,
+        ctx,
+    )
+
+    if len(sources) == 1:
+        reformat_one(
+            src=sources.pop(),
+            fast=fast,
+            write_back=write_back,
+            mode=mode,
+            report=report,
+        )
+    else:
+        reformat_many(
+            sources=sources, fast=fast, write_back=write_back, mode=mode, report=report
+        )
+
+    if verbose or not quiet:
+        out("Oh no! 💥 💔 💥" if report.return_code else "All done! ✨ 🍰 ✨")
+        click.secho(str(report), err=True)
+    ctx.exit(report.return_code)
+
+
+def get_sources(
+    *,
+    ctx: click.Context,
+    src: Tuple[str, ...],
+    quiet: bool,
+    verbose: bool,
+    include: str,
+    exclude: str,
+    force_exclude: Optional[str],
+    report: "Report",
+) -> Set[Path]:
+    """Compute the set of files to be formatted."""
     try:
         include_regex = re_compile_maybe_verbose(include)
     except re.error:
@@ -523,56 +564,56 @@ def main(
     except re.error:
         err(f"Invalid regular expression for exclude given: {exclude!r}")
         ctx.exit(2)
-    report = Report(check=check, diff=diff, quiet=quiet, verbose=verbose)
+    try:
+        force_exclude_regex = (
+            re_compile_maybe_verbose(force_exclude) if force_exclude else None
+        )
+    except re.error:
+        err(f"Invalid regular expression for force_exclude given: {force_exclude!r}")
+        ctx.exit(2)
+
     root = find_project_root(src)
     sources: Set[Path] = set()
-    path_empty(src, quiet, verbose, ctx)
+    path_empty(src, "No Path provided. Nothing to do 😴", quiet, verbose, ctx)
+    exclude_regexes = [exclude_regex]
+    if force_exclude_regex is not None:
+        exclude_regexes.append(force_exclude_regex)
+
     for s in src:
         p = Path(s)
         if p.is_dir():
             sources.update(
-                gen_python_files_in_dir(
-                    p, root, include_regex, exclude_regex, report, get_gitignore(root)
+                gen_python_files(
+                    p.iterdir(),
+                    root,
+                    include_regex,
+                    exclude_regexes,
+                    report,
+                    get_gitignore(root),
                 )
             )
-        elif p.is_file() or s == "-":
-            # if a file was explicitly given, we don't care about its extension
+        elif s == "-":
             sources.add(p)
+        elif p.is_file():
+            sources.update(
+                gen_python_files(
+                    [p], root, None, exclude_regexes, report, get_gitignore(root)
+                )
+            )
         else:
             err(f"invalid path: {s}")
-    if len(sources) == 0:
-        if verbose or not quiet:
-            out("No Python files are present to be formatted. Nothing to do 😴")
-        ctx.exit(0)
-
-    if len(sources) == 1:
-        reformat_one(
-            src=sources.pop(),
-            fast=fast,
-            write_back=write_back,
-            mode=mode,
-            report=report,
-        )
-    else:
-        reformat_many(
-            sources=sources, fast=fast, write_back=write_back, mode=mode, report=report
-        )
-
-    if verbose or not quiet:
-        out("Oh no! 💥 💔 💥" if report.return_code else "All done! ✨ 🍰 ✨")
-        click.secho(str(report), err=True)
-    ctx.exit(report.return_code)
+    return sources
 
 
 def path_empty(
-    src: Tuple[str, ...], quiet: bool, verbose: bool, ctx: click.Context
+    src: Sized, msg: str, quiet: bool, verbose: bool, ctx: click.Context
 ) -> None:
     """
     Exit if there is no `src` provided for formatting
     """
-    if not src:
+    if len(src) == 0:
         if verbose or not quiet:
-            out("No Path provided. Nothing to do 😴")
+            out(msg)
             ctx.exit(0)
 
 
@@ -613,12 +654,21 @@ def reformat_many(
     sources: Set[Path], fast: bool, write_back: WriteBack, mode: Mode, report: "Report"
 ) -> None:
     """Reformat multiple files using a ProcessPoolExecutor."""
+    executor: Executor
     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:
+        executor = ProcessPoolExecutor(max_workers=worker_count)
+    except OSError:
+        # we arrive here if the underlying system does not support multi-processing
+        # like in AWS Lambda, in which case we gracefully fallback to
+        # a ThreadPollExecutor with just a single worker (more workers would not do us
+        # any good due to the Global Interpreter Lock)
+        executor = ThreadPoolExecutor(max_workers=1)
+
     try:
         loop.run_until_complete(
             schedule_formatting(
@@ -633,7 +683,8 @@ def reformat_many(
         )
     finally:
         shutdown(loop)
-        executor.shutdown()
+        if executor is not None:
+            executor.shutdown()
 
 
 async def schedule_formatting(
@@ -5224,7 +5275,7 @@ def generate_ignored_nodes(leaf: Leaf) -> Iterator[LN]:
     """
     container: Optional[LN] = container_of(leaf)
     while container is not None and container.type != token.ENDMARKER:
-        if fmt_on(container):
+        if is_fmt_on(container):
             return
 
         # fix for fmt: on in children
@@ -5238,17 +5289,21 @@ def generate_ignored_nodes(leaf: Leaf) -> Iterator[LN]:
             container = container.next_sibling
 
 
-def fmt_on(container: LN) -> bool:
-    is_fmt_on = False
+def is_fmt_on(container: LN) -> bool:
+    """Determine whether formatting is switched on within a container.
+    Determined by whether the last `# fmt:` comment is `on` or `off`.
+    """
+    fmt_on = False
     for comment in list_comments(container.prefix, is_endmarker=False):
         if comment.value in FMT_ON:
-            is_fmt_on = True
+            fmt_on = True
         elif comment.value in FMT_OFF:
-            is_fmt_on = False
-    return is_fmt_on
+            fmt_on = False
+    return fmt_on
 
 
 def contains_fmt_on_at_column(container: LN, column: int) -> bool:
+    """Determine if children at a given column have formatting switched on."""
     for child in container.children:
         if (
             isinstance(child, Node)
@@ -5256,13 +5311,14 @@ def contains_fmt_on_at_column(container: LN, column: int) -> bool:
             or isinstance(child, Leaf)
             and child.column == column
         ):
-            if fmt_on(child):
+            if is_fmt_on(child):
                 return True
 
     return False
 
 
 def first_leaf_column(node: Node) -> Optional[int]:
+    """Returns the column of the first leaf child of a node."""
     for child in node.children:
         if isinstance(child, Leaf):
             return child.column
@@ -5693,11 +5749,11 @@ def get_gitignore(root: Path) -> PathSpec:
     return PathSpec.from_lines("gitwildmatch", lines)
 
 
-def gen_python_files_in_dir(
-    path: Path,
+def gen_python_files(
+    paths: Iterable[Path],
     root: Path,
-    include: Pattern[str],
-    exclude: Pattern[str],
+    include: Optional[Pattern[str]],
+    exclude_regexes: Iterable[Pattern[str]],
     report: "Report",
     gitignore: PathSpec,
 ) -> Iterator[Path]:
@@ -5709,19 +5765,13 @@ def gen_python_files_in_dir(
     `report` is where output about exclusions goes.
     """
     assert root.is_absolute(), f"INTERNAL ERROR: `root` must be absolute but is {root}"
-    for child in path.iterdir():
-        # First ignore files matching .gitignore
-        if gitignore.match_file(child.as_posix()):
-            report.path_ignored(child, "matches the .gitignore file content")
-            continue
-
+    for child in paths:
         # Then ignore with `exclude` option.
         try:
-            normalized_path = "/" + child.resolve().relative_to(root).as_posix()
+            normalized_path = child.resolve().relative_to(root).as_posix()
         except OSError as e:
             report.path_ignored(child, f"cannot be read because {e}")
             continue
-
         except ValueError:
             if child.is_symlink():
                 report.path_ignored(
@@ -5731,21 +5781,32 @@ def gen_python_files_in_dir(
 
             raise
 
+        # First ignore files matching .gitignore
+        if gitignore.match_file(normalized_path):
+            report.path_ignored(child, "matches the .gitignore file content")
+            continue
+
+        normalized_path = "/" + normalized_path
         if child.is_dir():
             normalized_path += "/"
 
-        exclude_match = exclude.search(normalized_path)
-        if exclude_match and exclude_match.group(0):
-            report.path_ignored(child, "matches the --exclude regular expression")
+        is_excluded = False
+        for exclude in exclude_regexes:
+            exclude_match = exclude.search(normalized_path) if exclude else None
+            if exclude_match and exclude_match.group(0):
+                report.path_ignored(child, "matches the --exclude regular expression")
+                is_excluded = True
+                break
+        if is_excluded:
             continue
 
         if child.is_dir():
-            yield from gen_python_files_in_dir(
-                child, root, include, exclude, report, gitignore
+            yield from gen_python_files(
+                child.iterdir(), root, include, exclude_regexes, report, gitignore
             )
 
         elif child.is_file():
-            include_match = include.search(normalized_path)
+            include_match = include.search(normalized_path) if include else True
             if include_match:
                 yield child