Fix project marked dirty when model expression unchanged

src/tailor/app.py

@@ -922,6 +922,12 @@ def load_project(self, filename):
             # remember filename for subsequent call to "Save"
             self._set_project_path(filename)
             self.update_recent_files(filename)
+            # rebuild UI on all tabs
+            current_idx = self.ui.tabWidget.currentIndex()
+            for idx in range(self.ui.tabWidget.count()):
+                self.ui.tabWidget.setCurrentIndex(idx)
+            self.ui.tabWidget.setCurrentIndex(current_idx)
+            # mark project as not dirty (clean)
             self.mark_project_dirty(False)
 
     def export_csv(self):

src/tailor/plot_model.py

@@ -260,7 +260,7 @@ def get_limits_from_data(self, padding=0.05) -> tuple[float]:
 
         return xmin, xmax, ymin, ymax
 
-    def update_model_expression(self, expression: str) -> None:
+    def update_model_expression(self, expression: str) -> bool:
         """Update the model expression.
 
         Update the stored (transformed) model expression independent of column
@@ -269,6 +269,9 @@ def update_model_expression(self, expression: str) -> None:
 
         Args:
             expression (str): the model expression.
+
+        Returns:
+            True if the expression is successfully updated, False otherwise.
         """
         # remove whitespace after newlines to prevent indentation errors
         expression = re.sub(r"\n\s*", "\n", expression)
@@ -281,6 +284,7 @@ def update_model_expression(self, expression: str) -> None:
             self._model_expression = expression
             self._model = None
             self.best_fit = None
+            return True
         else:
             if self._model_expression != transformed:
                 self._model_expression = transformed
@@ -294,6 +298,8 @@ def update_model_expression(self, expression: str) -> None:
                 else:
                     self.update_model_parameters()
                 self.best_fit = None
+                return True
+        return False
 
     def is_model_valid(self) -> bool:
         """Return if the model expression is a valid model.

src/tailor/plot_tab.py

@@ -382,12 +382,13 @@ def get_adjusted_limits(self):
     def update_model_expression(self):
         """Update the model expression and related UI."""
         expression = self.ui.model_func.toPlainText()
-        self.model.update_model_expression(expression)
+        is_updated = self.model.update_model_expression(expression)
         self.update_expression_border()
         self.update_params_ui()
         self.plot_initial_model()
         self.plot_best_fit()
-        self.main_window.mark_project_dirty()
+        if is_updated:
+            self.main_window.mark_project_dirty()
 
     def update_expression_border(self) -> None:
         """Update border of the model expression widget.

tests/test_plot_model.py

@@ -311,8 +311,9 @@ def test_update_model_expression(
         model.data_model.get_column_name.return_value = col_names[x_col]
         model.x_col = x_col
 
-        model.update_model_expression(expression)
+        is_updated = model.update_model_expression(expression)
 
+        assert is_updated is True
         model.data_model.get_column_name.assert_called_with(x_col)
         assert model._model_expression == transformed
         assert isinstance(model._model, lmfit.models.ExpressionModel)
@@ -334,9 +335,16 @@ def test_update_model_expression_keeps_fit_if_no_changes(
         bare_bones_data.data_model.get_column_name.return_value = "x"
         bare_bones_data.best_fit = sentinel.fit
 
-        bare_bones_data.update_model_expression("a*x+b")
+        is_updated = bare_bones_data.update_model_expression("a*x+b")
+        assert is_updated is False
         assert bare_bones_data.best_fit is sentinel.fit
 
+    def test_update_model_expression_returns_True_if_expr_is_broken(
+        self, bare_bones_data: PlotModel
+    ):
+        is_updated = bare_bones_data.update_model_expression("a*x+")
+        assert is_updated is True
+
     @pytest.mark.parametrize(
         "expression, transformed",
         [("x + (2 * ", "x + (2 * "), ("a * y + b", "a * y + b")],