Fix duplicated branch completion for git checkout issue 505

[bergmeister]

Fixes #505 by outputting only unique branches.
Instead of the proposed Sort-Object -Unique, I used Select-Object -Unique because:

• the 3 arrays for local branches, remote branches and tags are already sorted by themselves
• in order to not break existing behaviour and only fix the bug
• most user are less interested in tags and remote branches when using git checkout, therefore keeping the order as it was before makes sense
• better performance

[lzybkr]

You aren't trying to cache the branches, so you probably shouldn't save them in a script scope variable.
I think using the pipeline like this might be a bit more natural and avoids creating multiple arrays:

& {
    gitBranches $matches['ref'] $true
    gitRemoteUniqueBranches $matches['ref']
    gitTags $matches['ref']
} | Select-Object -Unique

You could use a function instead of the script block like I used here.

[bergmeister]

Thanks for the suggestion, you're right that this is the more efficient way of doing it.

[dahlbyk]

Shouldn't need the surrounding @(...) on these.

[bergmeister]

Well spotted, this was a left over from the previous version when I was using arrays.

[dahlbyk]

I just noticed this is targeting develop; I've opened #512 against master.

Still wish GitHub supported retargeting PRs...

[bergmeister]

Hmm, isn't that what gitflow would be for (except that it is from the command line)

[dahlbyk]

Despite the alignment of branch names, we don't use Git Flow. master is still targeting v0.x, develop is code with breaking changes working toward v1.0.