fix(matrix-service): correct implementation of `ISimpleMatrixService.…

…get_matrix_id`

antarest/matrixstore/service.py

@@ -86,8 +86,13 @@ def get_matrix_id(self, matrix: t.Union[t.List[t.List[float]], str]) -> str:
         Raises:
             TypeError: If the provided matrix is neither a matrix nor a link to a matrix.
         """
+        # noinspection SpellCheckingInspection
         if isinstance(matrix, str):
-            return matrix.lstrip("matrix://")
+            # str.removeprefix() is not available in Python 3.8
+            prefix = "matrix://"
+            if matrix.startswith(prefix):
+                return matrix[len(prefix) :]
+            return matrix
         elif isinstance(matrix, list):
             return self.create(matrix)
         else:

antarest/study/storage/variantstudy/model/command/create_binding_constraint.py

@@ -312,9 +312,11 @@ def _create_diff(self, other: "ICommand") -> t.List["ICommand"]:
 
         matrix_service = self.command_context.matrix_service
         for matrix_name in ["values", "less_term_matrix", "equal_term_matrix", "greater_term_matrix"]:
-            self_matrix = getattr(self, matrix_name)
-            other_matrix = getattr(other, matrix_name)
-            if self_matrix != other_matrix:
-                args[matrix_name] = matrix_service.get_matrix_id(other_matrix)
+            self_matrix = getattr(self, matrix_name)  # matrix, ID or `None`
+            other_matrix = getattr(other, matrix_name)  # matrix, ID or `None`
+            self_matrix_id = None if self_matrix is None else matrix_service.get_matrix_id(self_matrix)
+            other_matrix_id = None if other_matrix is None else matrix_service.get_matrix_id(other_matrix)
+            if self_matrix_id != other_matrix_id:
+                args[matrix_name] = other_matrix_id
 
         return [UpdateBindingConstraint(**args)]