[BUG] Formula not correctly evaluated

[MatWein]

Describe the bug
I have the following formula:
IF(Length(${DOC.Properties.832504:/current/XXX-WPNRID-D}) == 6, ${DOC.Properties.832504:/current/XXX-WPNRID-D}, null)
which is not correctly calculated. I tried to change the source code at:
io.atlasmap.core.DefaultAtlasFieldActionService#processActionForEachCollectionItem
from:
subField.setValue(value);
to:
fieldGroup.setValue(value);
That seems to work, but I don't know what side-effects this can have.

Attach .adm file and source document examples
mapping.zip

To Reproduce
Steps to reproduce the behavior:

1. Import adm file
2. Go to mapping of target DSER_DEPOT_BESTAND_WKN
3. use preview

Expected behavior
If the input field has exactly 6 characters than we want a mapping. Otherwise not.

Screenshots

Environment (please complete the following information):

• OS: Linux Mint 21
• Browser chrome
• Version 105

Additional context
Maybe you should think about using some existing frameworks / interpreter like Lua/JS/... instead of writing a custom formula interpreter.

[MatWein]

The above change does not seem to work and breaks other formulas.

Hint: formulas like:
NormalizeDouble('de',${DOC.Properties.832504:/current/XXX-NW-M}) * NormalizeDouble('de',${DOC.Properties.832504:/current/XXX-EINKURS-M})
are also not correctly evaluated.