defaultValueExpression doesn't work after setting survey.data fix #7276…

… (#7277)

src/question.ts

@@ -1861,15 +1861,18 @@ export class Question extends SurveyElement<Question>
     return runner;
   }
   protected setDefaultValue(): void {
+    this.setDefaultValueCore((val: any): void => {
+      if (!this.isTwoValueEquals(this.value, val)) {
+        this.value = val;
+      }
+    });
+  }
+  private setDefaultValueCore(func: (val: any) => void): void {
     this.defaultValueRunner = this.getDefaultRunner(this.defaultValueRunner, this.defaultValueExpression);
     this.setValueAndRunExpression(
       this.defaultValueRunner,
       this.getUnbindValue(this.defaultValue),
-      (val) => {
-        if (!this.isTwoValueEquals(this.value, val)) {
-          this.value = val;
-        }
-      }
+      (val) => func(val)
     );
   }
   protected isValueExpression(val: any): boolean {
@@ -2279,12 +2282,22 @@ export class Question extends SurveyElement<Question>
       newValue = this.valueFromDataCallback(newValue);
     }
     if (!this.checkIsValueCorrect(newValue)) return;
-    this.isChangingViaDefaultValue = this.isValueEmpty(newValue);
-    this.setQuestionValue(this.valueFromData(newValue));
-    this.isChangingViaDefaultValue = false;
+    const isEmpty = this.isValueEmpty(newValue);
+    if(!isEmpty && this.defaultValueExpression) {
+      this.setDefaultValueCore((val: any): void => {
+        this.updateValueFromSurveyCore(newValue, this.isTwoValueEquals(newValue, val));
+      });
+    } else {
+      this.updateValueFromSurveyCore(newValue, isEmpty);
+    }
     this.updateDependedQuestions();
     this.updateIsAnswered();
   }
+  private updateValueFromSurveyCore(newValue: any, viaDefaultVal: boolean): void {
+    this.isChangingViaDefaultValue = viaDefaultVal;
+    this.setQuestionValue(this.valueFromData(newValue));
+    this.isChangingViaDefaultValue = false;
+  }
   updateCommentFromSurvey(newValue: any): any {
     this.questionComment = newValue;
   }

tests/surveyquestiontests.ts

@@ -7283,6 +7283,21 @@ QUnit.test("Set array and convert it to a string & defaultValueExpression, bug#6
   assert.equal(q2.value, "a\nb\nc", "q2");
   assert.equal(q3.value, "a, b, c", "q3");
 });
+QUnit.test("defaultValueExpression & set data", function (assert) {
+  const survey = new SurveyModel({
+    elements: [
+      { type: "text", name: "q1" },
+      { type: "text", name: "q2" },
+      { type: "text", name: "q3", defaultValueExpression: "{q1} + {q2}" }
+    ]
+  });
+  const q1 = survey.getQuestionByName("q1");
+  const q3 = survey.getQuestionByName("q3");
+  survey.data = { q1: 1, q2: 2, q3: 3 };
+  assert.equal(q3.value, 3, "Value is set correctly");
+  q1.value = 5;
+  assert.equal(q3.value, 7, "Value is changed based on expression");
+});
 QUnit.test("question.resetValueIf, basic functionality", function (assert) {
   const survey = new SurveyModel({
     elements: [{