Setting 0 as default value for matrix dynamic rowCount property doesn…

…'t work as expected fix #8258 (#8259)

src/question_matrixdynamic.ts

@@ -66,11 +66,12 @@ export class QuestionMatrixDynamicModel extends QuestionMatrixDropdownModelBase
     sender: QuestionMatrixDynamicModel
   ) => any;
   private rowCounter = 0;
-  private initialRowCount: number = 2;
+  private initialRowCount: number;
   private setRowCountValueFromData: boolean = false;
 
   constructor(name: string) {
     super(name);
+    this.initialRowCount = this.getDefaultPropertyValue("rowCount");
     this.createLocalizableString("confirmDeleteText", this, false, "confirmDelete");
     var locAddRowText = this.createLocalizableString("addRowText", this);
     locAddRowText.onGetTextCallback = (text: string): string => {
@@ -827,6 +828,11 @@ export class QuestionMatrixDynamicModel extends QuestionMatrixDropdownModelBase
     this.setPropertyValueDirectly("rowCount", val.length);
     return true;
   }
+  updateValueFromSurvey(newValue: any, clearData: boolean = false): void {
+    this.setRowCountValueFromData = true;
+    super.updateValueFromSurvey(newValue, clearData);
+    this.setRowCountValueFromData = false;
+  }
   protected onBeforeValueChanged(val: any) {
     if (!val || !Array.isArray(val)) return;
     var newRowCount = val.length;

tests/question_matrixdynamictests.ts

@@ -9384,4 +9384,54 @@ QUnit.test("table: check animation options", function (assert) {
   assert.equal(questionHtmlElement.style.getPropertyValue("--animation-height"), "40px");
 
   tableHtmlElement.remove();
-});
+});
+QUnit.test("set data from the survey", function (assert) {
+  const survey = new SurveyModel({
+    elements: [
+      {
+        type: "matrixdynamic",
+        name: "matrix",
+        columns: [{ name: "col1" }]
+      }
+    ]
+  });
+  survey.data = { matrix: [{ col1: 1 }] };
+  const matrix = <QuestionMatrixDynamicModel>survey.getQuestionByName("matrix");
+  assert.equal(matrix.visibleRows.length, 1, "There one row");
+});
+QUnit.test("set data from the survey and default row count is 0", function (assert) {
+  const prop = Serializer.findProperty("matrixdynamic", "rowCount");
+  const prevValue = prop.defaultValue;
+  assert.equal(prevValue, 2, "The default rowCount value is 2");
+  prop.defaultValue = 0;
+  const survey = new SurveyModel({
+    elements: [
+      {
+        type: "matrixdynamic",
+        name: "matrix",
+        columns: [{ name: "col1" }]
+      }
+    ]
+  });
+  survey.data = { matrix: [{ col1: 1 }] };
+  const matrix = <QuestionMatrixDynamicModel>survey.getQuestionByName("matrix");
+  assert.equal(matrix.visibleRows.length, 1, "There one row");
+  Serializer.findProperty("matrixdynamic", "rowCount").defaultValue = 2;
+  prop.defaultValue = prevValue;
+});
+QUnit.test("set data from the defaultValue and ignore rowCount", function (assert) {
+  const survey = new SurveyModel({
+    elements: [
+      {
+        type: "matrixdynamic",
+        name: "matrix",
+        rowCount: 3,
+        defaultValue: [{ col1: 1 }],
+        columns: [{ name: "col1" }]
+      }
+    ]
+  });
+  survey.data = { matrix: [{ col1: 1 }] };
+  const matrix = <QuestionMatrixDynamicModel>survey.getQuestionByName("matrix");
+  assert.equal(matrix.visibleRows.length, 1, "There one row");
+});