Git: Deleting old local branches

Just looking at old local branches. They tend to proliferate, especially if you have a release cadence.

To list the local branches (the default), or list the branches according to a pattern, see the two examples directly below.

git branch
git branch --list "V2022*"

Small explanation of the output of the command:

• existing branches are listed
• the current branch will be highlighted in green and marked with an asterisk
• any branches checked out in linked worktrees will be highlighted in cyan and marked with a plus sign

I'm usually only interested in local branches, but "-r" shows remote-tracking branches and "-a" shows both remote and local branches, if you're interested.

Removing branches

git branch -D `git branch --list "V2022*"`

Bear in mind that branches that are used by a worktree cannot be deleted. Remove the worktree first.

Actually, I really like that behaviour.

Checking old branches

Apparently you can sort the list of branches based on last comitterdate.

git branch --sort=-committerdate # DESC

In the example above, you'll see branches that have been committed to recently at the top.

Finding a commit

This is nice, you can find which branches contain a certain commit quickly.

git branch --list --contains 089aafb331a08d19ed805fff6fea3846776980a0

Unfortunately, we're currently using git as a local repo, and svn remote, so there's a disconnect between commit hashes.

References

Git - git branch documentation

https://git-scm.com/docs/git-branch

StackOverflow - Can you delete multiple branches in one command with Git?

https://stackoverflow.com/questions/3670355/can-you-delete-multiple-branches-in-one-command-with-git

Kotlin: From List To Map

So I've been trying to make a Map from a List in Kotlin, and as I have not much experience with Kotlin and not much experience with Maps, I turn to the Internet.

Funnily enough, after getting it working, my IDE keeps giving me subtle hints that it can be shorter and more concise.

I thought it would be nice to put the steps here.

val primaryKeys = listOf(12L, 15L, 16L, 22L, 204L)
val firstTry = primaryKeys.map { it to getUser(it) }

In the example above it's not a Map yet, but it's a good first step.

As you can tell, it transforms your list into another List of type List<Pair<Long, User>>.

Kotlin has a toMap() method that does what we want.

    @Test
    fun testListToMapConversion() {
        val primaryKeys = listOf(12L, 15L, 16L, 22L, 204L)
        val map = primaryKeys.map { it to getUser(it) }.toMap()
        assertThat(map).isEqualTo(
            mapOf(
                12L to User(12L, "Bob"),
                15L to User(15L, "Jimmy"),
                16L to User(16L, "Jack"),
                22L to User(22L, "Henry"),
                204L to User(204L, "William")
            )
        )
    }

Now my IDE tells me this can be shortened.

    @Test
    fun testListToMapConversion() {
        val primaryKeys = listOf(12L, 15L, 16L, 22L, 204L)
        val map = primaryKeys.associate { it to getUser(it) }
        assertThat(map).isEqualTo(
            mapOf(
                12L to User(12L, "Bob"),
                15L to User(15L, "Jimmy"),
                16L to User(16L, "Jack"),
                22L to User(22L, "Henry"),
                204L to User(204L, "William")
            )
        )
    }

Now my IDE tells me this can be shortened AGAIN!

    @Test
    fun testListToMapConversion() {
        val primaryKeys = listOf(12L, 15L, 16L, 22L, 204L)
        val map = primaryKeys.associateWith { getUser(it) }
        assertThat(map).isEqualTo(
            mapOf(
                12L to User(12L, "Bob"),
                15L to User(15L, "Jimmy"),
                16L to User(16L, "Jack"),
                22L to User(22L, "Henry"),
                204L to User(204L, "William")
            )
        )
    }

Nice!

References

Syntax Highlighter

https://highlight.hohli.com/