Finally, let's use the new rich diff in black-shades :D

src/diff_shades/_diff.py

@@ -105,7 +105,6 @@ def marker_style(self) -> dict[str, Union[dict[str, str], str]]:
         }[self.theme]
 
     def raw_unified_diff(self) -> Iterator[str]:
-        differ = difflib.Differ()
         lines_lhs = self.lhs.splitlines()
         lines_rhs = self.rhs.splitlines()
         return unified_diff(
@@ -171,13 +170,7 @@ def build_unified_diff(self) -> RenderResult:
 
         for line in diff:
             if line.startswith("---"):
-                output_lines.append(
-                    Panel(
-                        line,
-                        box=box.DOUBLE,
-                        style="bold",
-                    )
-                )
+                output_lines.append(Text(line, style="bold"))
             elif line.startswith("@@"):
                 output_lines.append(
                     Panel(

src/diff_shades/cli.py

@@ -27,6 +27,7 @@
 
 import diff_shades
 import diff_shades.results
+from diff_shades._diff import Diff
 from diff_shades.analysis import (
     GIT_BIN,
     RESULT_COLORS,
@@ -36,7 +37,6 @@
 )
 from diff_shades.config import PROJECTS, Project
 from diff_shades.output import (
-    color_diff,
     make_analysis_summary,
     make_comparison_summary,
     make_project_details_table,
@@ -101,7 +101,7 @@ def compare_project_pair(
                 found_difference = True
 
             diff = diff_two_results(r1, r2, file=f"{project.name}:{file}", diff_failure=True)
-            console.print(color_diff(diff), highlight=False)
+            console.print(diff)
 
     return found_difference
 
@@ -355,7 +355,7 @@ def show(
                 console.print(escape(result.log), highlight=False)
         elif result.type == "reformatted":
             diff = result.diff(file_key)
-            console.print(color_diff(diff), highlight=False)
+            console.print(diff)
 
     elif project_key and not file_key:
         # TODO: implement a list view

src/diff_shades/output.py

@@ -8,7 +8,6 @@
 from typing import Sequence, Tuple, cast
 
 import rich
-from rich.markup import escape
 from rich.panel import Panel
 from rich.progress import BarColumn, Progress, TimeElapsedColumn
 from rich.table import Table
@@ -26,22 +25,6 @@
 console = rich.get_console()
 
 
-def color_diff(contents: str) -> str:
-    """Inject rich markup into the diff."""
-    lines = escape(contents).split("\n")
-    for i, line in enumerate(lines):
-        if line.startswith("+++") or line.startswith("---"):
-            line = "[bold]" + line + "[/]"
-        elif line.startswith("@@"):
-            line = "[cyan]" + line + "[/]"
-        elif line.startswith("+"):
-            line = "[green]" + line + "[/]"
-        elif line.startswith("-"):
-            line = "[red]" + line + "[/]"
-        lines[i] = line
-    return "\n".join(lines)
-
-
 def make_rich_progress() -> Progress:
     return Progress(
         "[progress.description]{task.description}",

src/diff_shades/results.py

@@ -2,7 +2,6 @@
 # > Analysis data representation & processing
 # ==========================================
 
-import difflib
 import hashlib
 import json
 import pickle
@@ -33,6 +32,7 @@
 import platformdirs
 
 import diff_shades
+from diff_shades._diff import Diff
 from diff_shades.config import Project
 
 CACHE_DIR: Final = Path(platformdirs.user_cache_dir("diff-shades"))
@@ -42,30 +42,15 @@
 ResultTypes = Literal["nothing-changed", "reformatted", "failed"]
 
 
-def unified_diff(a: str, b: str, a_name: str, b_name: str) -> str:
-    """Return a unified diff string between strings `a` and `b`."""
-    a_lines = a.splitlines(keepends=True)
-    b_lines = b.splitlines(keepends=True)
-    diff_lines = []
-    for line in difflib.unified_diff(a_lines, b_lines, fromfile=a_name, tofile=b_name, n=5):
-        # Work around https://bugs.python.org/issue2142. See also:
-        # https://www.gnu.org/software/diffutils/manual/html_node/Incomplete-Lines.html
-        if line[-1] == "\n":
-            diff_lines.append(line)
-        else:
-            diff_lines.append(line + "\n")
-            diff_lines.append("\\ No newline at end of file\n")
-    return "".join(diff_lines)
-
-
-def calculate_line_changes(diff: str) -> Tuple[int, int]:
+def calculate_line_changes(diff: Diff) -> Tuple[int, int]:
     """Return a two-tuple (additions, deletions) of a diff."""
     additions = 0
     deletions = 0
-    for line in diff.splitlines():
-        if line[0] == "+" and not line.startswith("+++"):
+    raw_diff = "\n".join(diff.raw_unified_diff())
+    for line in raw_diff.splitlines():
+        if line.startswith("+ "):
             additions += 1
-        elif line[0] == "-" and not line.startswith("---"):
+        elif line.startswith("- "):
             deletions += 1
 
     return additions, deletions
@@ -108,8 +93,8 @@ def __post_init__(self) -> None:
             object.__setattr__(self, "line_changes", changes)
 
     @lru_cache(maxsize=None)
-    def diff(self, filepath: str) -> str:
-        return unified_diff(self.src, self.dst, f"a/{filepath}", f"b/{filepath}")
+    def diff(self, filepath: str) -> Diff:
+        return Diff(self.src, self.dst, f"a/{filepath}", f"b/{filepath}")
 
 
 @dataclass(frozen=True)
@@ -193,7 +178,7 @@ def diff_two_results(
         first_dst = r1.dst if r1.type == "reformatted" else r1.src
         second_dst = r2.dst if r2.type == "reformatted" else r2.src
 
-    return unified_diff(first_dst, second_dst, f"a/{file}", f"b/{file}")
+    return Diff(first_dst, second_dst, f"a/{file}", f"b/{file}")
 
 
 # fmt: off