Code Flag Options (#2259)

Properly handles the diff, color, and fast option when black is run with
 the `--code` option.

Closes #2104, closes #1801.

AUTHORS.md

@@ -68,6 +68,7 @@ Multiple contributions by:
 - Gustavo Camargo
 - hauntsaninja
 - [Hadi Alqattan](mailto:alqattanhadizaki@gmail.com)
+- [Hassan Abouelela](mailto:hassan@hassanamr.com)
 - [Heaford](mailto:dan@heaford.com)
 - [Hugo Barrera](mailto::hugo@barrera.io)
 - Hugo van Kemenade

CHANGES.md

@@ -15,6 +15,7 @@
 - Respect `.gitignore` files in all levels, not only `root/.gitignore` file (apply
   `.gitignore` rules like `git` does) (#2225)
 - Restored compatibility with Click 8.0 on Python 3.6 when LANG=C used (#2227)
+- Fixed option usage when using the `--code` flag (#2259)
 - Add extra uvloop install + import support if in python env (#2258)
 - Fix --experimental-string-processing crash when matching parens are not found (#2283)
 - Make sure to split lines that start with a string operator (#2286)
@@ -43,6 +44,7 @@
 - Fix typos discovered by codespell (#2228)
 - Fix Vim plugin installation instructions. (#2235)
 - Add new Frequently Asked Questions page (#2247)
+- Removed safety checks warning for the `--code` option (#2259)
 - Fix encoding + symlink issues preventing proper build on Windows (#2262)
 
 ## 21.5b1

docs/usage_and_configuration/the_basics.md

@@ -68,13 +68,6 @@ $ black --code "print ( 'hello, world' )"
 print("hello, world")
 ```
 
-```{warning}
---check, --diff, and --safe / --fast have no effect when using -c / --code. Safety
-checks normally turned on by default that verify _Black_'s output are disabled as well.
-This is a bug which we intend to fix eventually. More details can be found in this [bug
-report](https://github.com/psf/black/issues/2104).
-```
-
 ### Writeback and reporting
 
 By default _Black_ reformats the files given and/or found in place. Sometimes you need

src/black/__init__.py

@@ -384,47 +384,61 @@ 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)
-    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,
-        extend_exclude=extend_exclude,
-        force_exclude=force_exclude,
-        report=report,
-        stdin_filename=stdin_filename,
-    )
+        # Run in quiet mode by default with -c; the extra output isn't useful.
+        # You can still pass -v to get verbose output.
+        quiet = True
 
-    path_empty(
-        sources,
-        "No Python files are present to be formatted. Nothing to do 😴",
-        quiet,
-        verbose,
-        ctx,
-    )
+    report = Report(check=check, diff=diff, quiet=quiet, verbose=verbose)
 
-    if len(sources) == 1:
-        reformat_one(
-            src=sources.pop(),
-            fast=fast,
-            write_back=write_back,
-            mode=mode,
-            report=report,
+    if code is not None:
+        reformat_code(
+            content=code, 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
+        sources = get_sources(
+            ctx=ctx,
+            src=src,
+            quiet=quiet,
+            verbose=verbose,
+            include=include,
+            exclude=exclude,
+            extend_exclude=extend_exclude,
+            force_exclude=force_exclude,
+            report=report,
+            stdin_filename=stdin_filename,
         )
 
+        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)
+        if code is None:
+            click.secho(str(report), err=True)
     ctx.exit(report.return_code)
 
 
@@ -512,6 +526,30 @@ def path_empty(
         ctx.exit(0)
 
 
+def reformat_code(
+    content: str, fast: bool, write_back: WriteBack, mode: Mode, report: Report
+) -> None:
+    """
+    Reformat and print out `content` without spawning child processes.
+    Similar to `reformat_one`, but for string content.
+
+    `fast`, `write_back`, and `mode` options are passed to
+    :func:`format_file_in_place` or :func:`format_stdin_to_stdout`.
+    """
+    path = Path("<string>")
+    try:
+        changed = Changed.NO
+        if format_stdin_to_stdout(
+            content=content, fast=fast, write_back=write_back, mode=mode
+        ):
+            changed = Changed.YES
+        report.done(path, changed)
+    except Exception as exc:
+        if report.verbose:
+            traceback.print_exc()
+        report.failed(path, str(exc))
+
+
 def reformat_one(
     src: Path, fast: bool, write_back: WriteBack, mode: Mode, report: "Report"
 ) -> None:
@@ -720,16 +758,27 @@ def format_file_in_place(
 
 
 def format_stdin_to_stdout(
-    fast: bool, *, write_back: WriteBack = WriteBack.NO, mode: Mode
+    fast: bool,
+    *,
+    content: Optional[str] = None,
+    write_back: WriteBack = WriteBack.NO,
+    mode: Mode,
 ) -> bool:
     """Format file on stdin. Return True if changed.
 
+    If content is None, it's read from sys.stdin.
+
     If `write_back` is YES, write reformatted code back to stdout. If it is DIFF,
     write a diff to stdout. The `mode` argument is passed to
     :func:`format_file_contents`.
     """
     then = datetime.utcnow()
-    src, encoding, newline = decode_bytes(sys.stdin.buffer.read())
+
+    if content is None:
+        src, encoding, newline = decode_bytes(sys.stdin.buffer.read())
+    else:
+        src, encoding, newline = content, "utf-8", ""
+
     dst = src
     try:
         dst = format_file_contents(src, fast=fast, mode=mode)
@@ -743,6 +792,8 @@ def format_stdin_to_stdout(
             sys.stdout.buffer, encoding=encoding, newline=newline, write_through=True
         )
         if write_back == WriteBack.YES:
+            # Make sure there's a newline after the content
+            dst += "" if dst[-1] == "\n" else "\n"
             f.write(dst)
         elif write_back in (WriteBack.DIFF, WriteBack.COLOR_DIFF):
             now = datetime.utcnow()

src/black/files.py

@@ -38,7 +38,7 @@ def find_project_root(srcs: Sequence[str]) -> Path:
     project root, the root of the file system is returned.
     """
     if not srcs:
-        return Path("/").resolve()
+        srcs = [str(Path.cwd().resolve())]
 
     path_srcs = [Path(Path.cwd(), src).resolve() for src in srcs]
 

tests/test_black.py

@@ -34,6 +34,7 @@
 from black import Feature, TargetVersion
 from black.cache import get_cache_file
 from black.debug import DebugVisitor
+from black.output import diff, color_diff
 from black.report import Report
 import black.files
 
@@ -63,6 +64,9 @@
 T = TypeVar("T")
 R = TypeVar("R")
 
+# Match the time output in a diff, but nothing else
+DIFF_TIME = re.compile(r"\t[\d-:+\. ]+")
+
 
 @contextmanager
 def cache_dir(exists: bool = True) -> Iterator[Path]:
@@ -2069,6 +2073,146 @@ def test_docstring_reformat_for_py27(self) -> None:
         actual = result.output
         self.assertFormatEqual(actual, expected)
 
+    @staticmethod
+    def compare_results(
+        result: click.testing.Result, expected_value: str, expected_exit_code: int
+    ) -> None:
+        """Helper method to test the value and exit code of a click Result."""
+        assert (
+            result.output == expected_value
+        ), "The output did not match the expected value."
+        assert result.exit_code == expected_exit_code, "The exit code is incorrect."
+
+    def test_code_option(self) -> None:
+        """Test the code option with no changes."""
+        code = 'print("Hello world")\n'
+        args = ["--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        self.compare_results(result, code, 0)
+
+    def test_code_option_changed(self) -> None:
+        """Test the code option when changes are required."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+        args = ["--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        self.compare_results(result, formatted, 0)
+
+    def test_code_option_check(self) -> None:
+        """Test the code option when check is passed."""
+        args = ["--check", "--code", 'print("Hello world")\n']
+        result = CliRunner().invoke(black.main, args)
+        self.compare_results(result, "", 0)
+
+    def test_code_option_check_changed(self) -> None:
+        """Test the code option when changes are required, and check is passed."""
+        args = ["--check", "--code", "print('hello world')"]
+        result = CliRunner().invoke(black.main, args)
+        self.compare_results(result, "", 1)
+
+    def test_code_option_diff(self) -> None:
+        """Test the code option when diff is passed."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+        result_diff = diff(code, formatted, "STDIN", "STDOUT")
+
+        args = ["--diff", "--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        # Remove time from diff
+        output = DIFF_TIME.sub("", result.output)
+
+        assert output == result_diff, "The output did not match the expected value."
+        assert result.exit_code == 0, "The exit code is incorrect."
+
+    def test_code_option_color_diff(self) -> None:
+        """Test the code option when color and diff are passed."""
+        code = "print('hello world')"
+        formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+        result_diff = diff(code, formatted, "STDIN", "STDOUT")
+        result_diff = color_diff(result_diff)
+
+        args = ["--diff", "--color", "--code", code]
+        result = CliRunner().invoke(black.main, args)
+
+        # Remove time from diff
+        output = DIFF_TIME.sub("", result.output)
+
+        assert output == result_diff, "The output did not match the expected value."
+        assert result.exit_code == 0, "The exit code is incorrect."
+
+    def test_code_option_safe(self) -> None:
+        """Test that the code option throws an error when the sanity checks fail."""
+        # Patch black.assert_equivalent to ensure the sanity checks fail
+        with patch.object(black, "assert_equivalent", side_effect=AssertionError):
+            code = 'print("Hello world")'
+            error_msg = f"{code}\nerror: cannot format <string>: \n"
+
+            args = ["--safe", "--code", code]
+            result = CliRunner().invoke(black.main, args)
+
+            self.compare_results(result, error_msg, 123)
+
+    def test_code_option_fast(self) -> None:
+        """Test that the code option ignores errors when the sanity checks fail."""
+        # Patch black.assert_equivalent to ensure the sanity checks fail
+        with patch.object(black, "assert_equivalent", side_effect=AssertionError):
+            code = 'print("Hello world")'
+            formatted = black.format_str(code, mode=DEFAULT_MODE)
+
+            args = ["--fast", "--code", code]
+            result = CliRunner().invoke(black.main, args)
+
+            self.compare_results(result, formatted, 0)
+
+    def test_code_option_config(self) -> None:
+        """
+        Test that the code option finds the pyproject.toml in the current directory.
+        """
+        with patch.object(black, "parse_pyproject_toml", return_value={}) as parse:
+            # Make sure we are in the project root with the pyproject file
+            if not Path("tests").exists():
+                os.chdir("..")
+
+            args = ["--code", "print"]
+            CliRunner().invoke(black.main, args)
+
+            pyproject_path = Path(Path().cwd(), "pyproject.toml").resolve()
+            assert (
+                len(parse.mock_calls) >= 1
+            ), "Expected config parse to be called with the current directory."
+
+            _, call_args, _ = parse.mock_calls[0]
+            assert (
+                call_args[0].lower() == str(pyproject_path).lower()
+            ), "Incorrect config loaded."
+
+    def test_code_option_parent_config(self) -> None:
+        """
+        Test that the code option finds the pyproject.toml in the parent directory.
+        """
+        with patch.object(black, "parse_pyproject_toml", return_value={}) as parse:
+            # Make sure we are in the tests directory
+            if Path("tests").exists():
+                os.chdir("tests")
+
+            args = ["--code", "print"]
+            CliRunner().invoke(black.main, args)
+
+            pyproject_path = Path(Path().cwd().parent, "pyproject.toml").resolve()
+            assert (
+                len(parse.mock_calls) >= 1
+            ), "Expected config parse to be called with the current directory."
+
+            _, call_args, _ = parse.mock_calls[0]
+            assert (
+                call_args[0].lower() == str(pyproject_path).lower()
+            ), "Incorrect config loaded."
+
 
 with open(black.__file__, "r", encoding="utf-8") as _bf:
     black_source_lines = _bf.readlines()