fix: map a file edited line for line as changed

scripts/profile_sync.py

@@ -524,7 +524,14 @@ def _map_changed(pin: list[str], head: list[str], lo: int, hi: int) -> AnchorRes
             "CHANGED", None, None, [], f"file over {MAX_MATCH_LINES} lines"
         )
     opcodes = _opcodes(pin, head)
-    if not any(tag == "equal" for tag, *_ in opcodes):
+    # A file whose every line was edited in place keeps no equal block, yet
+    # its lines still map one to one: fheroes2 version.txt holds one line,
+    # 1.0.11 at the pin and 1.1.17 at HEAD, and read GONE.
+    rewritten_in_place = len(opcodes) == 1 and (
+        opcodes[0][0] == "replace"
+        and opcodes[0][2] - opcodes[0][1] == opcodes[0][4] - opcodes[0][3]
+    )
+    if not rewritten_in_place and not any(tag == "equal" for tag, *_ in opcodes):
         return AnchorResult("GONE", None, None, [])
     new_lo = _map_index(opcodes, lo)
     new_hi = _map_index(opcodes, max(lo, hi - 1))

tests/test_profile_sync.py

@@ -387,6 +387,14 @@ class TestAnchorBlock(unittest.TestCase):
             self.assertEqual(result.status, "CHANGED")
             self.assertEqual(result.start, line)
 
+    def test_a_file_rewritten_line_for_line_is_changed_not_gone(self):
+        # fheroes2 version.txt:1 went from 1.0.11 to 1.1.17. With no
+        # unchanged line left the file read GONE and held the whole recale.
+        result = anchor_block(["1.0.11"], ["1.1.17"], 1, 1)
+        self.assertEqual((result.status, result.start, result.end), ("CHANGED", 1, 1))
+        result = anchor_block(["a = 1", "b = 2"], ["a = 3", "b = 4"], 2, 2)
+        self.assertEqual((result.status, result.start), ("CHANGED", 2))
+
     def test_gone_when_content_vanished(self):
         result = anchor_block(["a", "unique marker", "b"], ["x"] * 200, 2, 2)
         self.assertEqual(result.status, "GONE")