Support injecting Copyright Years based on file existence

[rvesse]

For some Copyright policies the years in the header should reflect only
the existence of that file not the project as a whole. While this can
be achieved by using ${license.git.copyrightCreationYear} and
${license.git.copyrightLastYear} in the header template you end up
generating awkward headers for some files e.g. 2021-2021. And you
cannot use ${license.git.copyrightYears} for this use case because that
will use the project inception year giving you something like 2019-2021.

This commit adds a new calculated property
${license.git.copyrightExistenceYears} which provides this information
and may be used in header templates where this behaviour is desired. This
should basically address the issue described in adobe/S3Mock#241

It also fixes a bug in GitLookup whereby if you had modified the file
it would incorrectly calculate the year range (because the creation year
was always defaulted to current year for modified files) and falsely flag
a license header as missing (or reformat unncessarily).

[mathieucarbou]

Sorry for the delay, I will merge and issue a 4.2.rc2.
Thanks!

[rvesse]

@mathieucarbou No worries, thanks for accepting this PR 👍

[mathieucarbou]

@rvesse : FYI a (minor) bug was discovered in a part implemented by @rremer so I will probably wait a little more before a new rc to get the chance to fix that. But if you need that sooner please let me know...

[rvesse]

@mathieucarbou No great rush on my end

[dbwiddis]

I just discovered this new feature and I'd like to implement it. Any chance of rc2 soon-ish? I tried using SNAPSHOT but it appears only the metadata is there and no actual release files.

[mathieucarbou]

I just discovered this new feature and I'd like to implement it. Any chance of rc2 soon-ish? I tried using SNAPSHOT but it appears only the metadata is there and no actual release files.

Yes it's planned next week 😊

[dbwiddis]

I'm running into an odd issue with this plugin. It's rewriting all headers and removing the earlier year, but only on OpenBSD.

For a sample file:

mvn verify

Changes the file thus:

- * Copyright (c) 2020-2021 ...
+ * Copyright (c) 2021 ...

This of course modifies the file so running it again turns it all into 2021-2022 on the next pass...

Should I create a new issue? Anything else I can help test/debug? Some configuration I'm missing?

[dbwiddis]

Ah, figured it out. On that VM I had a shallow clone so the year determination was only going back a few hundred commits.

So, the follow on question: would it be possible for the plugin to detect the presence of a shallow clone and not rewrite if that is the case?

[mathieucarbou]

@dbwiddis : I think this is a legitimate use case, yes. We could add an option in the plugin. I have created #252.
I won't / cannot work on it now, if you would like to contribute it, you are welcomed to 👍
The new RC was done on Monday, by the way ;-)