Get rid of tuple return values

bin/mechanicaldiff.py

@@ -6,7 +6,7 @@ import sys
 
 def filter_change_block(
     change_lines: list[str], search: str, replace: str
-) -> tuple[list[str] | None, bool]:
+) -> list[str] | None:
     removed_lines = []
     added_lines = []
     phase = "minus"
@@ -28,10 +28,10 @@ def filter_change_block(
         re.sub(search, replace, line) for line in removed_lines
     ]
     if transformed_removed == added_lines:
-        return change_lines, False
+        return change_lines
 
     if len(removed_lines) != len(added_lines):
-        return None, True
+        return None
 
     kept_lines = []
     for removed, added in zip(removed_lines, added_lines):
@@ -42,21 +42,20 @@ def filter_change_block(
             kept_lines.append(f" {removed}")
 
     if not kept_lines:
-        return None, True
+        return None
 
-    return kept_lines, True
+    return kept_lines
 
 
 def filter_hunk(
     hunk_lines: list[str], search: str, replace: str
-) -> tuple[list[str] | None, bool]:
+) -> list[str] | None:
     if not hunk_lines:
         return None, False
 
     header = hunk_lines[0]
     body = hunk_lines[1:]
     output_body: list[str] = []
-    left_out = False
 
     i = 0
     while i < len(body):
@@ -66,23 +65,17 @@ def filter_hunk(
             while i < len(body) and body[i].startswith(("+", "-")):
                 block.append(body[i])
                 i += 1
-            kept_block, block_left_out = filter_change_block(
-                block, search, replace
-            )
+            kept_block = filter_change_block(block, search, replace)
             if kept_block:
                 output_body.extend(kept_block)
-            else:
-                left_out = True
-            if block_left_out:
-                left_out = True
             continue
         output_body.append(line)
         i += 1
 
     if not any(line.startswith(("+", "-")) for line in output_body):
-        return None, True
+        return None
 
-    return [header] + output_body, left_out
+    return [header] + output_body
 
 
 def main() -> None:
@@ -130,14 +123,12 @@ def main() -> None:
 
         kept_hunks = []
         for hunk_lines in section["hunks"]:
-            filtered, hunk_left_out = filter_hunk(
-                hunk_lines, search, replace
-            )
+            filtered = filter_hunk(hunk_lines, search, replace)
             if filtered:
-                kept_hunks.append(filtered)
-            else:
+                if filtered != hunk_lines:
                     left_out = True
-            if hunk_left_out:
+                kept_hunks.append(filtered)
+            elif hunk_lines:
                 left_out = True
 
         if not kept_hunks: