SPSS: variable_value_label becomes None if any string value is longer than 8 characters

[wilfredrial]

Hi, not sure how to tell if this is an issue in the c library or pyreadstat. Apologies if it is the former.

As the title says, the "Values" column becomes "None" for a String variable in SPSS if any value is longer than 8 characters.

To reproduce:

import pandas as pd
import pyreadstat

var_values = {'mycol':{'-111':'err1'}}

# I thought setting var_format might have an effect but it seems it does not
# just leaving this here in case you want to compare
var_format = {} # {'mycol':'A50'} 

pyreadstat.write_sav(df=pd.DataFrame({'mycol':['-111', '123456789']}),  # 2nd value is 9 chars
                     dst_path='var_values_is_none.sav', 
                     variable_value_labels=var_values,
                     variable_format=var_format)


pyreadstat.write_sav(df=pd.DataFrame({'mycol':['-111', '12345678']}), # 2nd value is 8 chars
                     dst_path='var_values_is_NOT_none.sav', 
                     variable_value_labels=var_values,
                     variable_format=var_format)

Relevant versions:
python 3.12.3
pyreadstat 1.2.7
pandas 2.2.2