fix endless loop when dimensions that are not enough to fit one character

cocos/2d/CCLabelTextFormatter.cpp

@@ -151,16 +151,20 @@ bool LabelTextFormatter::multilineText(Label *theLabel)
             else
             {
                 StringUtils::trimUTF16Vector(last_word);
+                if (isStartOfLine)
+                    last_word.push_back(character);
 
                 last_word.push_back('\n');
-                
+
                 multiline_string.insert(multiline_string.end(), last_word.begin(), last_word.end());
                 last_word.clear();
+                if (!isStartOfLine)
+                    --j;
+
                 isStartOfWord = false;
                 isStartOfLine = false;
                 startOfWord = -1;
                 startOfLine = -1;
-                --j;
             }
         }
         else

tests/cpp-tests/Classes/LabelTest/LabelTestNew.cpp

@@ -80,7 +80,8 @@ static std::function<Layer*()> createFunctions[] =
     CL(LabelIssue4428Test),
     CL(LabelIssue4999Test),
     CL(LabelLineHeightTest),
-    CL(LabelAdditionalKerningTest)
+    CL(LabelAdditionalKerningTest),
+    CL(LabelIssue8492Test)
 };
 
 #define MAX_LAYER    (sizeof(createFunctions) / sizeof(createFunctions[0]))
@@ -1814,3 +1815,21 @@ std::string LabelAdditionalKerningTest::subtitle() const
 {
     return "Testing additional kerning of label";
 }
+
+LabelIssue8492Test::LabelIssue8492Test()
+{
+    auto label = Label::createWithBMFont("fonts/bitmapFontChinese.fnt", "中国中国中国中国中国");
+    label->setDimensions(5,100);
+    label->setPosition(VisibleRect::center());
+    addChild(label);
+}
+
+std::string LabelIssue8492Test::title() const
+{
+    return "Reorder issue #8492";
+}
+
+std::string LabelIssue8492Test::subtitle() const
+{
+    return "Work fine when dimensions are not enough to fit one character";
+}

tests/cpp-tests/Classes/LabelTest/LabelTestNew.h

@@ -509,6 +509,17 @@ private:
     Label* label;
 };
 
+class LabelIssue8492Test : public AtlasDemoNew
+{
+public:
+    CREATE_FUNC(LabelIssue8492Test);
+
+    LabelIssue8492Test();
+
+    virtual std::string title() const override;
+    virtual std::string subtitle() const override;
+};
+
 // we don't support linebreak mode
 
 #endif