In the event more than 3 rows contain formuls the following exception occurs: There was 1 error: 1) testAddIntegers(org.apache.poi.hssf.usermodel.TestFormulas) java.lang.ArrayIndexOutOfBoundsException at org.apache.poi.util.LittleEndian.putNumber(LittleEndian.java:536) at org.apache.poi.util.LittleEndian.putShort(LittleEndian.java:243) at org.apache.poi.hssf.record.SelectionRecord.serialize(SelectionRecord.java:262) at org.apache.poi.hssf.model.Sheet.serialize(Sheet.java:584) at org.apache.poi.hssf.usermodel.HSSFWorkbook.getBytes(HSSFWorkbook.java:522) at org.apache.poi.hssf.usermodel.HSSFWorkbook.write(HSSFWorkbook.java:474) at org.apache.poi.hssf.usermodel.TestFormulas.testAddIntegers(TestFormulas.java:130) at org.apache.poi.hssf.usermodel.TestFormulas.main(TestFormulas.java:157)
*** Bug 8593 has been marked as a duplicate of this bug. ***
Turned out that formulas only worked by cooincidence. There was a horrid mismatch between Formula Records and Value Records aggregate. Basically we couldn't handle records whose size changed later. Calculating it earlier was more efficient but later lets us handle this. At some point this should be revisited for optimization. If some manner of lightweight notification could be performed then we could calculate size early and only update the deltas. Might not be worth it for most sheets. (Then again...it might) Another approach might make a collection of only VariableSizeCellRecords (of which there are fewer on average) and only calculate them at the end. Regardless this works now.