python refs vs refs

tests/restyle.py

@@ -7,7 +7,9 @@
 import subprocess
 import contextlib
 
-from dataclasses import dataclass
+from dataclasses import dataclass, fields
+from dataclasses import field as dataclass_field
+
 
 GIT_ROOT = pathlib.Path(
     subprocess.check_output(
@@ -89,11 +91,11 @@ class Changed:
 
 @dataclass
 class Context:
-    append_hunk: bool
-    deleted: bool
-    file: str
-    hunk: list[str]
-    markers: list[str]
+    append_hunk: bool = False
+    deleted: bool = False
+    file: str = ""
+    hunk: list[str] = dataclass_field(default_factory=list)
+    markers: list[str] = dataclass_field(default_factory=list)
 
 
 # naive git-diff parser for clang-format aftercare
@@ -108,28 +110,24 @@ def changed_files():
         universal_newlines=True,
     )
 
-    def reset_context(line):
+    def reset_context(ctx):
+        other = Context()
+        for field in fields(other):
+            setattr(ctx, field.name, getattr(other, field.name))
+
+    def reset_with_line(ctx, line):
+        reset_context(ctx)
         if line:
-            hunk = [line]
-        else:
-            hunk = []
-
-        return Context(
-            append_hunk=False,
-            deleted=False,
-            file="",
-            hunk=hunk,
-            markers=[],
-        )
+            ctx.hunk = [line]
 
     def pop(out, context, line):
         if ctx.file and ctx.hunk and ctx.markers:
             out.append(Changed(ctx.file, "\n".join(ctx.hunk), ", ".join(ctx.markers)))
 
-        context = reset_context(line)
+        reset_with_line(context, line)
 
     out = []
-    ctx = reset_context(None)
+    ctx = Context()
 
     for line in proc.stdout.split("\n"):
         # '--- a/path/to/changed/file' most likely
@@ -180,6 +178,7 @@ def warning_changed(changed: Changed):
 SUMMARY_PATH = pathlib.Path(os.environ.get("GITHUB_STEP_SUMMARY", os.devnull))
 SUMMARY_OUTPUT = SUMMARY_PATH.open("a")
 
+
 def summary_diff(changed: Changed):
     with contextlib.redirect_stdout(SUMMARY_OUTPUT):
         print(f"# {changed.file} (suggested change)")