fix: output encoded binary to avoid newline issues

src/darker/__main__.py

@@ -32,6 +32,7 @@
 )
 from darker.help import get_extra_instruction
 from darker.import_sorting import apply_isort, isort
+from darker.terminal import output
 from darker.utils import debug_dump, glob_any
 from darker.verification import ASTVerifier, BinarySearch, NotEquivalentError
 from darkgraylib.command_line import (
@@ -416,7 +417,7 @@ def print_diff(
             n=5,  # Black shows 5 lines of context, do the same
         )
     )
-    print(colorize(diff, "diff", use_color))
+    output(colorize(diff, "diff", use_color), end="\n")
 
 
 def print_source(new: TextDocument, use_color: bool) -> None:
@@ -429,11 +430,11 @@ def print_source(new: TextDocument, use_color: bool) -> None:
                 PythonLexer,
             ) = _import_pygments()  # type: ignore
         except ImportError:
-            print(new.string, end="")
+            output(new.string)
         else:
-            print(highlight(new.string, PythonLexer(), TerminalFormatter()), end="")
+            output(highlight(new.string, PythonLexer(), TerminalFormatter()))
     else:
-        print(new.string, end="")
+        output(new.string)
 
 
 def _import_pygments():  # type: ignore

src/darker/terminal.py

@@ -0,0 +1,10 @@
+"""Terminal output helpers."""
+
+import sys
+
+
+def output(*args: str, end: str = "") -> None:
+    """Print encoded binary output to terminal, with no newline by default."""
+    sys.stdout.buffer.write(*[arg.encode() for arg in args])
+    if end:
+        sys.stdout.buffer.write(end.encode())

src/darker/utils.py

@@ -4,6 +4,7 @@
 from pathlib import Path
 from typing import Collection, List
 
+from darker.terminal import output
 from darkgraylib.utils import DiffChunk
 
 logger = logging.getLogger(__name__)
@@ -14,14 +15,14 @@ def debug_dump(black_chunks: List[DiffChunk], edited_linenums: List[int]) -> Non
     if logger.getEffectiveLevel() > logging.DEBUG:
         return
     for offset, old_lines, new_lines in black_chunks:
-        print(80 * "-")
+        output(80 * "-", end="\n")
         for delta, old_line in enumerate(old_lines):
             linenum = offset + delta
             edited = "*" if linenum in edited_linenums else " "
-            print(f"{edited}-{linenum:4} {old_line}")
+            output(f"{edited}-{linenum:4} {old_line}", end="\n")
         for _, new_line in enumerate(new_lines):
-            print(f" +     {new_line}")
-    print(80 * "-")
+            output(f" +     {new_line}", end="\n")
+    output(80 * "-", end="\n")
 
 
 def glob_any(path: Path, patterns: Collection[str]) -> bool: