Using setAttachment with the name of an exiting attachment minus its extensions overrides it

Example of reproduction step from the UI:

• Creation a new document
• Upload a first "test.txt" attachment
• Upload a second "test" attachment

Excepted result:

Two attachments in version 1.1 are listed in the attachments pane

Actual result:

test.txt is in version 1.2 and has the content of "test" (is, "test.txt" has been overriden)