Skip KEEP_TOGETHER in case of AreaBreak

DEVSIX-5156

Author: ars18wrw

layout/src/main/java/com/itextpdf/layout/renderer/AbstractRenderer.java

@@ -2104,7 +2104,12 @@ protected boolean isAbsolutePosition() {
     }
 
     protected boolean isKeepTogether() {
-        return Boolean.TRUE.equals(getPropertyAsBoolean(Property.KEEP_TOGETHER));
+        return isKeepTogether(null);
+    }
+
+    boolean isKeepTogether(IRenderer causeOfNothing) {
+        return Boolean.TRUE.equals(getPropertyAsBoolean(Property.KEEP_TOGETHER))
+                && !(causeOfNothing instanceof AreaBreakRenderer);
     }
 
     // Note! The second parameter is here on purpose. Currently occupied area is passed as a value of this parameter in

layout/src/main/java/com/itextpdf/layout/renderer/BlockRenderer.java

@@ -196,7 +196,7 @@ public LayoutResult layout(LayoutContext layoutContext) {
                 fixOccupiedAreaIfOverflowedX(overflowX, layoutBox);
 
                 result = new LayoutResult(LayoutResult.NOTHING, null, null, childRenderer);
-                boolean isKeepTogether = isKeepTogether();
+                boolean isKeepTogether = isKeepTogether(childRenderer);
                 int layoutResult = anythingPlaced && !isKeepTogether ? LayoutResult.PARTIAL : LayoutResult.NOTHING;
                 AbstractRenderer[] splitAndOverflowRenderers = createSplitAndOverflowRenderers(childPos, layoutResult, result, waitingFloatsSplitRenderers, waitingOverflowFloatRenderers);
 
@@ -798,7 +798,7 @@ LayoutResult processNotFullChildResult(LayoutContext layoutContext,
                 return null;
             }
         } else if (result.getStatus() == LayoutResult.NOTHING) {
-            boolean keepTogether = isKeepTogether();
+            boolean keepTogether = isKeepTogether(causeOfNothing);
             int layoutResult = anythingPlaced && !keepTogether ? LayoutResult.PARTIAL : LayoutResult.NOTHING;
 
             AbstractRenderer[] splitAndOverflowRenderers = createSplitAndOverflowRenderers(childPos, layoutResult,

layout/src/main/java/com/itextpdf/layout/renderer/FlexContainerRenderer.java

@@ -203,7 +203,7 @@ LayoutResult processNotFullChildResult(LayoutContext layoutContext,
                                            Set<Rectangle> nonChildFloatingRendererAreas, IRenderer causeOfNothing,
                                            boolean anythingPlaced, int childPos, LayoutResult result) {
 
-        final boolean keepTogether = isKeepTogether();
+        final boolean keepTogether = isKeepTogether(causeOfNothing);
 
         final AbstractRenderer[] splitAndOverflowRenderers = createSplitAndOverflowRenderers(
                 childPos, result.getStatus(), result, waitingFloatsSplitRenderers, waitingOverflowFloatRenderers);

layout/src/main/java/com/itextpdf/layout/renderer/ParagraphRenderer.java

@@ -311,7 +311,7 @@ protected LayoutResult directLayout(LayoutContext layoutContext) {
                     lastYLine = layoutBox.getY() + layoutBox.getHeight();
                     firstLineInBox = true;
                 } else {
-                    boolean keepTogether = isKeepTogether();
+                    boolean keepTogether = isKeepTogether(result.getCauseOfNothing());
                     if (keepTogether) {
                         floatRendererAreas.retainAll(nonChildFloatingRendererAreas);
                         return new MinMaxWidthLayoutResult(LayoutResult.NOTHING, null, null, this, null == result.getCauseOfNothing() ? this : result.getCauseOfNothing());

layout/src/main/java/com/itextpdf/layout/renderer/TableRenderer.java

@@ -882,8 +882,12 @@ public LayoutResult layout(LayoutContext layoutContext) {
                     }
                 }
 
-                if ((isKeepTogether() && 0 == lastFlushedRowBottomBorder.size()) && !Boolean.TRUE.equals(getPropertyAsBoolean(Property.FORCED_PLACEMENT))) {
-                    return new LayoutResult(LayoutResult.NOTHING, null, null, this, null == firstCauseOfNothing ? this : firstCauseOfNothing);
+                if (isKeepTogether(firstCauseOfNothing)
+                        && 0 == lastFlushedRowBottomBorder.size()
+                        && !Boolean.TRUE.equals(getPropertyAsBoolean(Property.FORCED_PLACEMENT))) {
+                    return new LayoutResult(LayoutResult.NOTHING, null, null, this, null == firstCauseOfNothing
+                            ? this
+                            : firstCauseOfNothing);
                 } else {
                     int status = ((occupiedArea.getBBox().getHeight()
                             - (null == footerRenderer ? 0 : footerRenderer.getOccupiedArea().getBBox().getHeight())

layout/src/test/java/com/itextpdf/layout/KeepTogetherTest.java

@@ -73,6 +73,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.test.annotations.LogMessage;
 import com.itextpdf.test.annotations.LogMessages;
 import com.itextpdf.test.annotations.type.IntegrationTest;
+
+import java.io.ByteArrayOutputStream;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Ignore;
@@ -131,6 +133,25 @@ public void keepTogetherParagraphTest01() throws IOException, InterruptedExcepti
         Assert.assertNull(new CompareTool().compareByContent(outFile, cmpFileName, destinationFolder, "diff"));
     }
 
+    @Test
+    public void skipKeepTogetherInCaseOfAreaBreak() throws IOException, InterruptedException {
+        PdfDocument pdfDoc = new PdfDocument(new PdfWriter(new ByteArrayOutputStream()));
+        Document doc = new Document(pdfDoc);
+
+        Div keptTogetherDiv = new Div();
+        keptTogetherDiv.setKeepTogether(true);
+
+        AreaBreak areaBreak = new AreaBreak();
+        keptTogetherDiv.add(areaBreak);
+
+        doc.add(keptTogetherDiv);
+
+        // If this line is not triggered, then an NPE occurred
+        Assert.assertTrue(true);
+
+        doc.close();
+    }
+
     @Test
     @LogMessages(messages = {
             @LogMessage(messageTemplate = LogMessageConstant.ELEMENT_DOES_NOT_FIT_AREA)