Formula field of new history plots is broken

[Giorgio Pintaudi]

Steps to reproduce:

• Create a new history plot with multiple variables
• Try to set the formula field of at least one variable, for example: 0.5*x

Error message:

[mhttpd,ERROR] [odb.cxx:7063:db_set_data_index,ERROR] "/History/Display/Data size (MB)/All/Formula" invalid element data size 256, expected 32

When it is happening:

Always when setting the formula field

Tested on commit:

$  git log --name-status HEAD^..HEAD
commit f2b4c9a963f6d9d6da6df904826ad9fb3895f0e5 (HEAD -> develop, origin/develop)
Author: Konstantin Olchanski <olchansk@home>
Date:   Sun Feb 14 10:24:12 2021 -0800

    Fix fetest event generator fuzzer

M       progs/fetest.cxx

‌

[Stefan Ritt]

Fixed in last commit (Link). The "Formula" array is not automatically extended from 32 chars to 256. We need 256 chars because some formulas need more than 32 chars (linearization of PT1000 sensors).