Talend: what does "Component variable are used in the copied elements" mean?

On Talend Studio, you may get the message "Component variables are used in copied elements, do you want to rename them automatically?" when copying and pasting components. What does this message actually mean?

The question is not very explicit, but is very important for your treatment (hence the interest of this article...). This means that there are named variables in the components that are going to be pasted and if you don't rename them (by answering 'No'), the pasted components will refer to the copied source components.

An example will be more telling: in the screenshot below, there is a tFileList_1 linked to a tFileInputDelimited_1. This last component uses as source "((String)globalMap.get("tFileList_1_CURRENT_FILE"))" to iterate over all the files in tFileList_1.

If you copy-paste these 2 components, the message from Talend Studio is displayed to ask you the question of renaming.

• If you answer "yes", asking for the renaming, tFileInputDelimited_2 will refer to the created tFileList_2. This is of course the desired behavior.
• If you answer "no", not asking for the renaming, tFileInputDelimited_2 will refer to the initial tFileList_1.

In most situations, it is therefore essential to rename the variables, choosing "yes" to the question posed by Talend Studio, but there are of course cases where this renaming is not to be done . My advice is therefore to check, once the elements have been pasted, that each component is using the desired variables.