The fingerprint plugin is no more able to take fingerprint of a "hidden" file such as .git/FETCH_HEAD.
I am assuming it is an issue in Jenkins core, though the plugin might not have reflected a change to how files are detected in core.
How to reproduce:
Install the finger print plugin. Create a simple job. In the workspace directory create a directory '.git' (note the leading dot), create a FETCH_HEAD file in it with some random content.
Add a build step 'fingerprint' files.
In the field "Files to fingerprint" fill in '.git/FETCH_HEAD'.
A red error message is shown:
'.git/FETCH_HEAD' doesn't match anything: even '.git' doesn't exist
The help message give a link to "the workspace", that file browser does show a .git directory containing a FETCH_HEAD file.
I have a "child" job fetching several git repositories. I would like it to just fingerprints any FETCH_HEAD files (**/.git/FETCH_HEAD) to have a quick and fast way to track jobs dependencies.
I am pretty sure it used to work in version 1.431 and was broken with 1.458. Still broken with 1.473.