How do I add a comment to a subtask and reference subtasks fields in the comment?

[Andrew Madar]

I know I can use for example {{issue.key}} but if I have a custom field for the subtask, what would be the smart value for it?

I tried a few things with no success:

{{fieldname}}

{{issue.subtask.fieldname}}

{{issue.fields.fieldname}}

[Mikael Sandberg]

The smart value is either the field name or the custom field Id:

{{issue.fieldname}}

{{issue.customfield_XXXXX}}

Sub-tasks are treated the same way as a regular issue.

You can get the custom field Id if you go to Settings > Issues > Custom fields, locate the field and then hover over one of the options under the three dot menu. The URL that is shown contains the id.