OpenXLSX::XLDocument is not saving the same string into another workbook

[NK01]

The issue example:

OpenXLSX::XLDocument doc; // this is used to create and save the workbook
std::vector<std::vector<std::string>> data; // this contains the data to be saved in 2D matrix for easy insertion into excel

doc.create(workbook1, true);
OpenXLSX::XLWorksheet wks = doc.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc.save()
doc.close()

doc.create(workbook2, true);
wks = doc.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc.save()
doc.close()

In the above example the second workbook does not contain any data, but if I change some data in the std::vector<std::vector<std::string>> data matrix then the changed data is inserted into the second matrix but not anything else

Currently the workaround is to create a new OpenXLSX::XLDocument doc like this:

OpenXLSX::XLDocument doc; // this is used to create and save the workbook
std::vector<std::vector<std::string>> data; // this contains the data to be saved in 2D matrix for easy insertion into excel

doc.create(workbook1, true);
OpenXLSX::XLWorksheet wks = doc.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc.save()
doc.close()

OpenXLSX::XLDocument doc2;
doc2.create(workbook2, true);
wks = doc2.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc2.save()
doc2.close()

then everything works as expected.
Is the first way not correct?

[aral-matrix]

Hi @NK01 & thank you for reporting this issue. It sounds like a bug: I see nothing wrong with re-using the XLDocument variable like you do. I will have a look to understand why the document seems to not properly "reset" on ::create, when I find some time - I am currently quite busy & I hope this isn't too urgent, since you have a workaround.

My apologies if this takes a few weeks for me to address.

[NK01]

Thank you for the response and yeah it is not urgent, as I have already put the workaround in the code. No worries for the delay, take your time

[aral-matrix]

Thank you for your patience - I just wanted to give you a heads-up: I will start looking into this this week, and might have questions - so if you can check for notifications to respond within a few hours that would be great. :)

[NK01]

Thank you for taking up this issue, I am not that well versed in programming to actually contribute to the code however I can help you with any question you might have about the issue

[aral-matrix]

Okay, so I was able to reproduce the issue and isolate the root cause: the shared strings cache was not being deleted, so that if you re-assigned the same strings that were already cached to cells in a new document, the XLDocument would think "oh, I already have those strings" and store the indexes from the previous document, but never generate the shared strings table. If you would assign strings not yet cached, they would have been added, but with the wrong index (I didn't verify, the fix was easy enough).

Patched in bf5fe8a - if you could have a look at the development-aral branch, to confirm that this fixes the issue for you as well, that would be appreciated.

Thank you for flagging this, technically speaking this was a memory leak as well (memory from the cache was never released).

[SeaonyongPark]

The below looks similar to this issue.
When opening XLDocument, there is no initialization for list or deque. There might be a problem when opening multiple excel files in application. Would you look at this issue?

void XLDocument::open(const std::string& fileName)
{
// Check if a document is already open. If yes, close it.
if (m_archive.isOpen()) close(); // TBD: consider throwing if a file is already open.
m_filePath = fileName;
m_archive.open(m_filePath);

m_sharedStringCache.clear();   // Added to initialize
m_data.clear();                         // Added to initialize

// ===== Add and open the Relationships and [Content_Types] files for the document level.
std::string relsFilename = "_rels/.rels";
m_data.emplace_back(this, "[Content_Types].xml");
m_data.emplace_back(this, relsFilename);

[NK01]

I have tried the patch bf5fe8a - at the development-aral branch, and can confirm that

OpenXLSX::XLDocument doc; // this is used to create and save the workbook
std::vector<std::vector<std::string>> data; // this contains the data to be saved in 2D matrix for easy insertion into excel

doc.create(workbook1, true);
OpenXLSX::XLWorksheet wks = doc.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc.save()
doc.close()

doc.create(workbook2, true);
wks = doc.workbook().worksheet("Sheet1");
// Inserting data into the workbook
for (std::size_t i = 0; i < data.size(); ++i) 
{
    for (std::size_t j = 0; j < data[i].size(); ++j)
    {
        wks.cell(OpenXLSX::XLCellReference(static_cast<uint16_t>(i) + 1, static_cast<uint16_t>(j) + 1)).value() = data[i][j];
    }
}
doc.save()
doc.close()

works without any issues

[aral-matrix]

@NK01: Thank you for testing :) I will mark this issue as closed when I merge the patch into the main branch!

[aral-matrix]

@SeaonyongPark:

The below looks similar to this issue. When opening XLDocument, there is no initialization for list or deque. There might be a problem when opening multiple excel files in application. Would you look at this issue?

void XLDocument::open(const std::string& fileName) {
[..]
m_sharedStringCache.clear();   // Added to initialize
m_data.clear();                         // Added to initialize

Thank you for the suggestion, but those are actually initialized with default values in the XLDocument.hpp class definition, line 359 & 360.

        mutable std::list<XLXmlData>    m_data {};              /**<  */
        mutable std::deque<std::string> m_sharedStringCache {}; /**<  */
        mutable XLSharedStrings         m_sharedStrings {};     /**<  */

Clearing them as you suggest is exactly the patch that I added, but in XLDocument::close, which is also invoked by the destructor, if forgotten by the user.

[aral-matrix]

Okay, this patch is merged into main - closing the issue as resolved.