fix: the return type is wrong for int +/- float (#277)

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           submodules: "recursive"
 
@@ -20,7 +20,7 @@ jobs:
         run: echo ::set-output name=tag::${GITHUB_REF#refs/tags/}
 
       - name: Set up Python 3.9
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: "3.9"
 

.github/workflows/tests.yml

@@ -48,7 +48,7 @@ jobs:
 
       - name: Install Poetry
         shell: bash
-        run: curl -fsSL https://install.python-poetry.org | python - -y
+        run: curl -fsSL https://install.python-poetry.org | python - -y --version 1.4.0
 
       - name: Update PATH
         if: ${{ matrix.os != 'Windows' }}

tests/test_items.py

@@ -579,6 +579,29 @@ def test_item_array_of_dicts_converted_to_aot():
     )
 
 
+def test_add_float_to_int():
+    content = "[table]\nmy_int = 2043"
+    doc = parse(content)
+    doc["table"]["my_int"] += 5.0
+    assert doc["table"]["my_int"] == 2048.0
+    assert isinstance(doc["table"]["my_int"], float)
+
+
+def test_sub_float_from_int():
+    content = "[table]\nmy_int = 2048"
+    doc = parse(content)
+    doc["table"]["my_int"] -= 5.0
+    assert doc["table"]["my_int"] == 2043.0
+    assert isinstance(doc["table"]["my_int"], float)
+
+
+def test_sub_int_from_float():
+    content = "[table]\nmy_int = 2048.0"
+    doc = parse(content)
+    doc["table"]["my_int"] -= 5
+    assert doc["table"]["my_int"] == 2043.0
+
+
 def test_add_sum_int_with_float():
     content = "[table]\nmy_int = 2048.3"
     doc = parse(content)

tomlkit/items.py

@@ -647,28 +647,28 @@ def as_string(self) -> str:
         return self._raw
 
     def __add__(self, other):
-        return self._new(int(self._raw) + other)
+        result = super().__add__(other)
+        if result is NotImplemented:
+            return result
+        return self._new(result)
 
     def __radd__(self, other):
         result = super().__radd__(other)
-
-        if isinstance(other, Integer):
-            return self._new(result)
-
-        return result
+        if result is NotImplemented:
+            return result
+        return self._new(result)
 
     def __sub__(self, other):
         result = super().__sub__(other)
-
+        if result is NotImplemented:
+            return result
         return self._new(result)
 
     def __rsub__(self, other):
         result = super().__rsub__(other)
-
-        if isinstance(other, Integer):
-            return self._new(result)
-
-        return result
+        if result is NotImplemented:
+            return result
+        return self._new(result)
 
     def _new(self, result):
         raw = str(result)