Math formula is empty

lpfinke · April 11, 2021, 6:05pm

Hi there,

I am using Ubuntu 20 with lo 6.4.6.2. While working on a document build under an older lo version I encounter a strange behaviour:

I can view all my embedded math formula, but when I try to open and reddit it, the formula clears. This cannot be recovered.

Any help is appreciated.

Lars Peer

See example file: (most formulas behave like told)

FormelLeer.odt

ajlittoz · April 11, 2021, 6:15pm

Edit your question and attach a sample file still exhibiting the problem. To attach, click on edit link, scroll to bottom, type two Enter and use the paperclip tool.

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lpfinke · April 12, 2021, 5:55am

Please see edited question above, Thx

mikekaganski · April 12, 2021, 6:12am

While working on a document build under an older lo version I encounter a strange behaviour

I see the problem locally, using Version: 7.1.2.2 (x64) / LibreOffice Community
Build ID: 8a45595d069ef5570103caea1b71cc9d82b2aae4
CPU threads: 12; OS: Windows 10.0 Build 19042; UI render: Skia/Raster; VCL: win
Locale: ru-RU (ru_RU); UI: en-US
Calc: CL.

But examining the formula data in the document, it has totally wrong XML - starting with wrong root element name.

E.g., /Object 158/content.xml:

<?xml version="1.0" encoding="UTF-8"?>
<matrix-covered xmlns="http://www.w3.org/1998/Math/MathML"
                display-details="block">
    <sender-city>
    ...

must have been:

<?xml version="1.0" encoding="UTF-8"?>
<math xmlns="http://www.w3.org/1998/Math/MathML"
      display="block">
    <semantics>
    ...

It was generated using a broken generator.

mikekaganski · April 12, 2021, 6:17am

I remember we had a problem like this once - a bug made some XML elements “shifted”. I suppose that this document can only be recovered by opening the ODT, and manually replacing relevant element names with correct names.

ajlittoz · April 12, 2021, 6:28am

I used 4.1.6.2 (I hope this is an old enough version) to display your file. Same issue. The XML shows the description of the formula is empty or contains varying number of {. Writer uses the embedded equivalent picture to display the formula.

Hagar_Delest · April 12, 2021, 6:15am

I see the same on y Windows 10 machine with your file.

To retrieve the formulas without retyping all, make a copy of the file and open it with an archive manager. Then go to the /Object xxx folders and open the contents.xml file. At the end, you can copy the formula code (highlighted below) and paste it in a new formula to replace the former one:

To be done for each formula…

It may be worth a bug report to highlight this retro-compatibility issue.

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mikekaganski · April 12, 2021, 6:19am

Unfortunately, this is not a retro-compatibility issue, it is a bug in the version used for generation of the document… It created a file broken for both earlier and later versions.

I wrote “unfortunately”, because this way, it’s impossible to “fix” the bug in a way that the file would read correctly in current versions. But I seem to remember that that bug was in a “early adopter” version (like X.Y.0 or X.Y.1); yet, I may be mistaken.

Hagar_Delest · April 12, 2021, 6:38am

Thanks for the clarification!

Another point against the use of fresh versions for production work.