Add colors to diffs printed by --dry

Author: albertas

README.md

@@ -20,11 +20,16 @@ To see unused code findings:
 deadcode .
 ```
 
-To see suggested fixes:
+To see suggested fixes for all files:
 ```shell
 deadcode . --fix --dry
 ```
 
+To see suggested fixes for only `foo.py` file:
+```shell
+deadcode . --fix --dry foo.py
+```
+
 To fix:
 ```shell
 deadcode . --fix

deadcode/actions/fix_or_show_unused_code.py

@@ -8,6 +8,7 @@
 from deadcode.data_types import Args
 from deadcode.visitor.code_item import CodeItem
 from deadcode.utils.flatten_lists import flatten_list
+from deadcode.utils.add_colors_to_diff import add_colors_to_diff
 from deadcode.visitor.ignore import _match
 
 
@@ -41,7 +42,11 @@ def fix_or_show_unused_code(unused_items: Iterable[CodeItem], args: Args) -> str
                 with open(filename, "r") as f:
                     diff = unified_diff(f.readlines(), updated_file_content_lines, fromfile=filename, tofile=filename)
                     # TODO: consider printing result instantly to save memory
-                    result.append("".join(diff))
+                    diff_str = "".join(diff)
+                    if args.no_color:
+                        result.append(diff_str)
+                    else:
+                        result.append(add_colors_to_diff(diff_str))
 
             elif args.fix:
                 with open(filename, "w") as f:

deadcode/tests/cli_args/test_dry.py

@@ -1,6 +1,6 @@
 from deadcode.cli import main
 from deadcode.tests.base import BaseTestCase
-from textwrap import dedent
+from deadcode.utils.fix_indent import fix_indent
 
 
 class TestDryCliOption(BaseTestCase):
@@ -17,7 +17,7 @@ class UnusedClass:
         self.assertEqual(
             unused_names,
             (
-                dedent(
+                fix_indent(
                     """\
                 foo.py:1:0: DC03 Class `UnusedClass` is never used
 
@@ -56,7 +56,7 @@ class UnusedClass:
         self.assertEqual(
             unused_names,
             (
-                dedent(
+                fix_indent(
                     """\
                 foo.py:1:0: DC03 Class `UnusedClass` is never used
 
@@ -99,7 +99,7 @@ def unused_function():
         unused_names = main(["ignore_names_by_pattern.py", "--no-color", "--dry"])
         self.assertEqual(
             unused_names,
-            dedent(
+            fix_indent(
                 """\
                 bar.py:1:0: DC02 Function `unused_function` is never used
                 foo.py:1:0: DC03 Class `UnusedClass` is never used
@@ -155,7 +155,7 @@ def unused_function():
         unused_names = main(["ignore_names_by_pattern.py", "--no-color", "--dry", "foo.py"])
         self.assertEqual(
             unused_names,
-            dedent(
+            fix_indent(
                 """\
                 bar.py:1:0: DC02 Function `unused_function` is never used
                 foo.py:1:0: DC03 Class `UnusedClass` is never used
@@ -224,7 +224,7 @@ class UnusedClass:
         self.assertEqual(
             unused_names,
             (
-                dedent(
+                fix_indent(
                     """\
                 foo.py:1:0: DC03 Class `UnusedClass` is never used
 
@@ -249,3 +249,70 @@ class UnusedClass:
                     print("Dont change this file")"""
             }
         )
+
+    def test_coloring_of_a_diff(self):
+        self.files = {
+            "foo.py": """
+                class UnusedClass:
+                    pass
+
+                print("Dont change this file")""",
+            "bar.py": """
+                def unused_function():
+                    pass
+
+                with open("tmp.txt", "r") as unused_var:
+                    pass
+
+                print("Dont change this file")""",
+        }
+
+        unused_names = main(["ignore_names_by_pattern.py", "--dry"])
+        self.assertEqual(
+            unused_names,
+            fix_indent(
+                """\
+                bar.py:1:0: \x1b[91mDC02\x1b[0m Function `\x1b[1munused_function\x1b[0m` is never used
+                bar.py:4:29: \x1b[91mDC01\x1b[0m Variable `\x1b[1munused_var\x1b[0m` is never used
+                foo.py:1:0: \x1b[91mDC03\x1b[0m Class `\x1b[1mUnusedClass\x1b[0m` is never used
+
+                \x1b[31m--- bar.py\x1b[0m
+                \x1b[32m+++ bar.py\x1b[0m
+                @@ -1,7 +1,4 @@
+                \x1b[31m-def unused_function():\x1b[0m
+                \x1b[31m-    pass\x1b[0m
+                \x1b[31m-\x1b[0m
+                \x1b[31m-with open("tmp.txt", "r") as unused_var:\x1b[0m
+                \x1b[32m+with open("tmp.txt", "r"):\x1b[0m
+                     pass
+                 
+                 print("Dont change this file")
+
+                \x1b[31m--- foo.py\x1b[0m
+                \x1b[32m+++ foo.py\x1b[0m
+                @@ -1,4 +1 @@
+                \x1b[31m-class UnusedClass:\x1b[0m
+                \x1b[31m-    pass\x1b[0m
+                \x1b[31m-\x1b[0m
+                 print("Dont change this file")
+                """
+            ),
+        )
+
+        self.assertFiles(
+            {
+                "foo.py": """
+                class UnusedClass:
+                    pass
+
+                print("Dont change this file")""",
+                "bar.py": """
+                def unused_function():
+                    pass
+
+                with open("tmp.txt", "r") as unused_var:
+                    pass
+
+                print("Dont change this file")""",
+            }
+        )

deadcode/tests/utils/test_add_colors_to_diff.py

@@ -0,0 +1,38 @@
+from unittest import TestCase
+from deadcode.utils.fix_indent import fix_indent
+
+from deadcode.utils.add_colors_to_diff import add_colors_to_diff
+
+
+class TestAddColorsToDiff(TestCase):
+    def test_add_colors_to_diff(self):
+        diff = fix_indent(
+            """\
+            --- foo.py
+            +++ foo.py
+            @@ -1,4 +1 @@
+            -class UnusedClass:
+            -    pass
+            -
+            -with open("tmp.txt") as f:
+            +with open("tmp.txt"):
+                pass"""
+        )
+
+        colorful_diff = add_colors_to_diff(diff)
+
+        self.assertEqual(
+            colorful_diff,
+            fix_indent(
+                """\
+            \x1b[31m--- foo.py\x1b[0m
+            \x1b[32m+++ foo.py\x1b[0m
+            @@ -1,4 +1 @@
+            \x1b[31m-class UnusedClass:\x1b[0m
+            \x1b[31m-    pass\x1b[0m
+            \x1b[31m-\x1b[0m
+            \x1b[31m-with open("tmp.txt") as f:\x1b[0m
+            \x1b[32m+with open("tmp.txt"):\x1b[0m
+                pass"""
+            ),
+        )

deadcode/utils/add_colors_to_diff.py

@@ -0,0 +1,10 @@
+def add_colors_to_diff(diff: str) -> str:
+    colorful_lines = []
+    for line in diff.split("\n"):
+        colorful_line = line
+        if line.startswith("-"):
+            colorful_line = f"\033[31m{colorful_line}\033[0m"
+        if line.startswith("+"):
+            colorful_line = f"\033[32m{colorful_line}\033[0m"
+        colorful_lines.append(colorful_line)
+    return "\n".join(colorful_lines)