fix(config): deterministic and transactional state->config migration

desloppify/base/config.py

@@ -377,10 +377,16 @@ def _migrate_single_state_file(config: dict, path: Path) -> bool:
         return False
 
     _merge_legacy_state_config(config, old_config)
-    _strip_config_from_state_file(path, state_data)
     return True
 
 
+def _state_files_for_migration(state_dir: Path) -> list[Path]:
+    """Return state files in deterministic migration order."""
+    scoped = sorted(state_dir.glob("state-*.json"), key=lambda p: p.name)
+    root = sorted(state_dir.glob("state.json"), key=lambda p: p.name)
+    return [*scoped, *root]
+
+
 def _migrate_from_state_files(config_path: Path) -> dict:
     """Migrate config keys from state-*.json files into config.json.
 
@@ -393,12 +399,13 @@ def _migrate_from_state_files(config_path: Path) -> dict:
     if not state_dir.exists():
         return config
 
-    state_files = list(state_dir.glob("state-*.json")) + list(
-        state_dir.glob("state.json")
-    )
+    state_files = _state_files_for_migration(state_dir)
     migrated_any = False
+    migrated_files: list[Path] = []
     for sf in state_files:
-        migrated_any = _migrate_single_state_file(config, sf) or migrated_any
+        if _migrate_single_state_file(config, sf):
+            migrated_any = True
+            migrated_files.append(sf)
 
     if migrated_any and config:
         try:
@@ -407,6 +414,12 @@ def _migrate_from_state_files(config_path: Path) -> dict:
             log_best_effort_failure(
                 logger, f"save migrated config to {config_path}", exc
             )
+        else:
+            for sf in migrated_files:
+                state_data = _load_state_file_payload(sf)
+                if state_data is None:
+                    continue
+                _strip_config_from_state_file(sf, state_data)
 
     return config
 

desloppify/tests/core/test_config.py

@@ -4,6 +4,7 @@
 
 import pytest
 
+import desloppify.base.config as config_mod
 from desloppify.base.config import (
     CONFIG_SCHEMA,
     _migrate_from_state_files,
@@ -321,6 +322,27 @@ def test_merges_multiple_state_files(self, tmp_path):
         assert "ex1" in result.get("exclude", [])
         assert "ex2" in result.get("exclude", [])
 
+    def test_scalar_merge_order_is_deterministic(self, tmp_path):
+        state_dir = tmp_path
+        state_dir.mkdir(exist_ok=True)
+
+        state_a = {
+            "version": 1,
+            "config": {"target_strict_score": 90},
+            "issues": {},
+        }
+        state_z = {
+            "version": 1,
+            "config": {"target_strict_score": 10},
+            "issues": {},
+        }
+        (state_dir / "state-z.json").write_text(json.dumps(state_z))
+        (state_dir / "state-a.json").write_text(json.dumps(state_a))
+        config_path = state_dir / "config.json"
+
+        result = _migrate_from_state_files(config_path)
+        assert result.get("target_strict_score") == 90
+
     def test_no_state_files_returns_empty(self, tmp_path):
         config_path = tmp_path / "config.json"
         result = _migrate_from_state_files(config_path)
@@ -378,3 +400,27 @@ def test_legacy_language_keys_from_state_are_not_auto_migrated(self, tmp_path):
         result = _migrate_from_state_files(config_path)
         assert "csharp_corroboration_min_signals" not in result
         assert "csharp_high_fanout_threshold" not in result
+
+    def test_save_failure_does_not_strip_source_state_config(
+        self, tmp_path, monkeypatch
+    ):
+        state_dir = tmp_path
+        state_dir.mkdir(exist_ok=True)
+        state_data = {
+            "version": 1,
+            "config": {"ignore": ["smells::*::debug"]},
+            "issues": {},
+        }
+        state_file = state_dir / "state-python.json"
+        state_file.write_text(json.dumps(state_data))
+        config_path = state_dir / "config.json"
+
+        def _raise_save(*_args, **_kwargs):
+            raise OSError("disk full")
+
+        monkeypatch.setattr(config_mod, "save_config", _raise_save)
+
+        result = _migrate_from_state_files(config_path)
+        assert "smells::*::debug" in result.get("ignore", [])
+        updated_state = json.loads(state_file.read_text())
+        assert "config" in updated_state