give proper error message for invalid putpixel color type

Tests/test_image_access.py

@@ -328,6 +328,36 @@ class TestCffi(AccessTest):
             assert im.convert("RGB").getpixel((0, 0)) == (255, 0, 0)
 
 
+class TestImagePutPixelError(AccessTest):
+    def test_putpixel_error_message(self):
+        for mode, reason, accept_tuple in [
+            ("L", "color must be int or tuple", True),
+            ("LA", "color must be int or tuple", True),
+            ("RGB", "color must be int or tuple", True),
+            ("RGBA", "color must be int or tuple", True),
+            ("I", "color must be int", False),
+            ("I;16", "color must be int", False),
+            ("BGR;15", "color must be int", False),
+        ]:
+            im = hopper(mode)
+
+            for v in ["foo", 1.0, None]:
+                with pytest.raises(TypeError, match=reason):
+                    im.putpixel((0, 0), v)
+
+            if not accept_tuple:
+                with pytest.raises(TypeError, match=reason):
+                    im.putpixel((0, 0), (10,))
+
+            with pytest.raises(OverflowError):
+                im.putpixel((0, 0), 2 ** 80)
+
+        for mode in ["BGR;15"]:
+            im = hopper(mode)
+            with pytest.raises(ValueError, match="unrecognized image mode"):
+                im.putpixel((0, 0), 0)
+
+
 class TestEmbeddable:
     @pytest.mark.skipif(
         not is_win32() or on_ci(),

src/_imaging.c

@@ -521,12 +521,20 @@ getink(PyObject* color, Imaging im, char* ink)
     if (im->type == IMAGING_TYPE_UINT8 ||
         im->type == IMAGING_TYPE_INT32 ||
         im->type == IMAGING_TYPE_SPECIAL) {
-                if (PyLong_Check(color)) {
+        if (PyLong_Check(color)) {
-                        r = PyLong_AsLongLong(color);
+            r = PyLong_AsLongLong(color);
+            if (r == -1 && PyErr_Occurred()) {
+                return NULL;
+            }
             rIsInt = 1;
-                }
+        } else if (im->type == IMAGING_TYPE_UINT8) {
-                if (r == -1 && PyErr_Occurred()) {
+            if (!PyTuple_Check(color)) {
-                    rIsInt = 0;
+                PyErr_SetString(PyExc_TypeError, "color must be int or tuple");
+                return NULL;
+            }
+        } else {
+            PyErr_SetString(PyExc_TypeError, "color must be int");
+            return NULL;
         }
     }
 
@@ -570,9 +578,6 @@ getink(PyObject* color, Imaging im, char* ink)
         return ink;
     case IMAGING_TYPE_INT32:
         /* signed integer */
-        if (rIsInt != 1) {
-            return NULL;
-        }
         itmp = r;
         memcpy(ink, &itmp, sizeof(itmp));
         return ink;
@@ -587,9 +592,6 @@ getink(PyObject* color, Imaging im, char* ink)
         return ink;
     case IMAGING_TYPE_SPECIAL:
         if (strncmp(im->mode, "I;16", 4) == 0) {
-            if (rIsInt != 1) {
-                return NULL;
-            }
             ink[0] = (UINT8) r;
             ink[1] = (UINT8) (r >> 8);
             ink[2] = ink[3] = 0;