Add support for jgit log search for latest commit when path is given.

[shashken]

Add support for jgit log search for latest commit when path is given.
Solved an edge case where the latest found was actually one commit prior to the latest commit (the merge to master)
Tries to solve #332
@bgalek - please review
@farrukhnajmi FYI

[bgalek]

Hi, looks fine, but we're gonna need some tests, could you add some?

[shashken]

@bgalek I'm not familiar with the tests in this project, could you maybe help me out here?

[bgalek]

@shashken sure! look here https://github.com/allegro/axion-release-plugin/tree/master/src/integration/groovy/pl/allegro/tech/build/axion/release
some tests already use CurrentVersion task so it should be easy to setup few tests based on that ;)

[shashken]

@bgalek I implemented two tests to catch 2 cases for the last position, and implemented a new way to choose between lastCommit and the nearest merge.
Can you please review?

[shashken]

hmm I thought of something, I think the whole approach for monorepo with excludeDirs was wrong to begin with,
Take this example case:
A (Head)
|
B (Tag 1.2.0)
|
C
|
D
|
E (latest change found for path)
|
F (no change to path)
|
G (Tag 1.1.0)

what we expect:
A (1.2.0)
B-E (1.1.0-snapshot)
F-G (1.1.0)

what is currently happening:
A (1.2.0-snapshot)
B (1.2.0-snapshot)
C-G( 1.1.0-snapshot)

This happens because we check if latestChange == tag, but we dont have to use this approach, instead we can go
Diffformatter.setPathFilter(path);
Diffformatter.scan(latestChange, taggedCommit)

[bgalek]

I'll try to look at it today

[shashken]

@bgalek I implemented a new logic for monorepo versioning in versionResolver.
If its a monorepo case (path given) it checks for git differences between latestchange and found tag version commit to determine if its a snapshot version.
Added several tests for those behaviours.
The previous fix I proposed is irrelevant here, as this is a completely different approach to determine snapshot versioning for monorepos.
WTYT?

[shashken]

@bgalek tag me here if you have any comments/suggestions

[shashken]

@bgalek Reminder :) I used a local version of the plugin and it seems to solve the snapshot issue completely

[bgalek]

@shashken I gave it a quick look, overall seems ok, I'would change some formatting and names, but we can do it later, please give me little bit more time to think about the solution - but I think it's gonna be ok! we should also update docs :)

[shashken]

@bgalek I committed some formatting and naming changes. better now? also what do you want to change in docs? the usage of the plugin remains the same :)
Do you think we can merge this until the beginning of next week maybe?

[bgalek]

@shashken cool! Sure, let's say monday - I'll also review some more PR's till then!

[shashken]

@bgalek let me know what you want me to change, I'm available today

[bgalek]

I'll prepare a release, as promised! :)

[bgalek]

@shashken debug left ;)

[shashken]

removed @bgalek

[bgalek]

LGTM, thx for your contribution!