Pretty Terminal Output

.flake8

@@ -5,3 +5,4 @@ ignore = E203, E266, E501, W503
 max-line-length = 80
 max-complexity = 18
 select = B,C,E,F,W,T4,B9
+per-file-ignores=src/black/const.py:C408

CHANGES.md

@@ -34,6 +34,7 @@
   Jupyter Notebooks (#2744)
 - Deprecate `--experimental-string-processing` and move the functionality under
   `--preview` (#2789)
+- Black now styles your output logs in the CLI using pretty colours ✨ (#2787)
 
 ### Packaging
 

src/black/__init__.py

@@ -36,8 +36,13 @@
 from dataclasses import replace
 from mypy_extensions import mypyc_attr
 
-from black.const import DEFAULT_LINE_LENGTH, DEFAULT_INCLUDES, DEFAULT_EXCLUDES
-from black.const import STDIN_PLACEHOLDER
+from black.const import (
+    DEFAULT_LINE_LENGTH,
+    DEFAULT_INCLUDES,
+    DEFAULT_EXCLUDES,
+    STDIN_PLACEHOLDER,
+    LogLevel,
+)
 from black.nodes import STARS, syms, is_simple_decorator_expression
 from black.nodes import is_string_token
 from black.lines import Line, EmptyLineTracker
@@ -438,7 +443,7 @@ def main(
         if root:
             out(
                 f"Identified `{root}` as project root containing a {method}.",
-                fg="blue",
+                style=LogLevel.info,
             )
 
             normalized = [
@@ -453,14 +458,14 @@ def main(
                     for _norm, source in normalized
                 ]
             )
-            out(f"Sources to be formatted: {srcs_string}", fg="blue")
+            out(f"Sources to be formatted: {srcs_string}", style=LogLevel.info)
 
         if config:
             config_source = ctx.get_parameter_source("config")
             if config_source in (ParameterSource.DEFAULT, ParameterSource.DEFAULT_MAP):
-                out("Using configuration from project root.", fg="blue")
+                out("Using configuration from project root.", style=LogLevel.info)
             else:
-                out(f"Using configuration in '{config}'.", fg="blue")
+                out(f"Using configuration in '{config}'.", style=LogLevel.info)
 
     error_msg = "Oh no! 💥 💔 💥"
     if required_version and required_version != __version__:
@@ -548,7 +553,10 @@ def main(
     if verbose or not quiet:
         if code is None and (verbose or report.change_count or report.failure_count):
             out()
-        out(error_msg if report.return_code else "All done! ✨ 🍰 ✨")
+        out(
+            error_msg if report.return_code else "All done! ✨ 🍰 ✨",
+            style=LogLevel.success,
+        )
         if code is None:
             click.echo(str(report), err=True)
     ctx.exit(report.return_code)

src/black/const.py

@@ -1,4 +1,23 @@
+from enum import Enum
+from typing_extensions import TypedDict
+
 DEFAULT_LINE_LENGTH = 88
 DEFAULT_EXCLUDES = r"/(\.direnv|\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|venv|\.svn|_build|buck-out|build|dist)/"  # noqa: B950
 DEFAULT_INCLUDES = r"(\.pyi?|\.ipynb)$"
 STDIN_PLACEHOLDER = "__BLACK_STDIN_FILENAME__"
+
+
+class Empty(TypedDict):
+    pass
+
+
+class LogLevel(Enum):
+    none: Empty = {}
+    trace = dict(fg="cyan", dim=True)
+    debug = dict(fg="green", dim=True)
+    info = dict(fg="blue")
+    success = dict(fg="green", bold=True)
+    warning = dict(fg="yellow")
+    error = dict(fg="red")
+    critical = dict(fg="red", bold=True)
+    notice = dict(fg="magenta", bold=True)

src/black/output.py

@@ -8,34 +8,34 @@
 from mypy_extensions import mypyc_attr
 import tempfile
 
-from click import echo, style
+from click import echo, style as _style
+
+from black.const import LogLevel
 
 
 @mypyc_attr(patchable=True)
 def _out(message: Optional[str] = None, nl: bool = True, **styles: Any) -> None:
     if message is not None:
-        if "bold" not in styles:
-            styles["bold"] = True
-        message = style(message, **styles)
+        message = _style(message, **styles)
     echo(message, nl=nl, err=True)
 
 
 @mypyc_attr(patchable=True)
-def _err(message: Optional[str] = None, nl: bool = True, **styles: Any) -> None:
-    if message is not None:
-        if "fg" not in styles:
-            styles["fg"] = "red"
-        message = style(message, **styles)
-    echo(message, nl=nl, err=True)
+def out(
+    message: Optional[str] = None,
+    nl: bool = True,
+    style: LogLevel = LogLevel.none,
+    **_styles: Any,
+) -> None:
+    styles = style.value.copy()
+    if style:
+        styles.update(_styles)
 
-
-@mypyc_attr(patchable=True)
-def out(message: Optional[str] = None, nl: bool = True, **styles: Any) -> None:
     _out(message, nl=nl, **styles)
 
 
 def err(message: Optional[str] = None, nl: bool = True, **styles: Any) -> None:
-    _err(message, nl=nl, **styles)
+    return out(message, nl, LogLevel.error, **styles)
 
 
 def ipynb_diff(a: str, b: str, a_name: str, b_name: str) -> str:

src/black/report.py

@@ -7,6 +7,7 @@
 
 from click import style
 
+from black import LogLevel
 from black.output import out, err
 
 
@@ -37,15 +38,21 @@ def done(self, src: Path, changed: Changed) -> None:
         if changed is Changed.YES:
             reformatted = "would reformat" if self.check or self.diff else "reformatted"
             if self.verbose or not self.quiet:
-                out(f"{reformatted} {src}")
+                out(f"{reformatted} {src}", style=LogLevel.trace)
             self.change_count += 1
         else:
             if self.verbose:
                 if changed is Changed.NO:
-                    msg = f"{src} already well formatted, good job."
+                    msg, style = (
+                        f"{src} already well formatted, good job.",
+                        LogLevel.success,
+                    )
                 else:
-                    msg = f"{src} wasn't modified on disk since last run."
-                out(msg, bold=False)
+                    msg, style = (
+                        f"{src} wasn't modified on disk since last run.",
+                        LogLevel.trace,
+                    )
+                out(msg, style=style, bold=False)
             self.same_count += 1
 
     def failed(self, src: Path, message: str) -> None:
@@ -55,7 +62,7 @@ def failed(self, src: Path, message: str) -> None:
 
     def path_ignored(self, path: Path, message: str) -> None:
         if self.verbose:
-            out(f"{path} ignored: {message}", bold=False)
+            out(f"{path} ignored: {message}", style=LogLevel.warning)
 
     @property
     def return_code(self) -> int:

tests/test_black.py

@@ -443,7 +443,7 @@ def out(msg: str, **kwargs: Any) -> None:
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.output._out", out), patch("black.output._err", err):
+        with patch("black.report.out", out), patch("black.report.err", err):
             report.done(Path("f1"), black.Changed.NO)
             self.assertEqual(len(out_lines), 1)
             self.assertEqual(len(err_lines), 0)
@@ -545,7 +545,7 @@ def out(msg: str, **kwargs: Any) -> None:
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.output._out", out), patch("black.output._err", err):
+        with patch("black.report.out", out), patch("black.report.err", err):
             report.done(Path("f1"), black.Changed.NO)
             self.assertEqual(len(out_lines), 0)
             self.assertEqual(len(err_lines), 0)
@@ -639,7 +639,7 @@ def out(msg: str, **kwargs: Any) -> None:
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.output._out", out), patch("black.output._err", err):
+        with patch("black.report.out", out), patch("black.report.err", err):
             report.done(Path("f1"), black.Changed.NO)
             self.assertEqual(len(out_lines), 0)
             self.assertEqual(len(err_lines), 0)
@@ -940,7 +940,8 @@ def out(msg: str, **kwargs: Any) -> None:
         def err(msg: str, **kwargs: Any) -> None:
             err_lines.append(msg)
 
-        with patch("black.output._out", out), patch("black.output._err", err):
+        with patch("tests.util.out", out), patch("tests.util.err", err):
+            black.output.out("test test")
             with self.assertRaises(AssertionError):
                 self.assertFormatEqual("j = [1, 2, 3]", "j = [1, 2, 3,]")