Why does Git use a colon (:) to delete remote branches?

Question

Why does Git use

git push <remote> :<branch>

as in

git push origin :featureA

to delete the branch featureA from the remote server?

I am interested in why the colon was used as the delete flag.

It's so different from git branch -d <localbranch>.

Why don't we do something like

git branch -d --remote origin <branchname>

or is there a deeper meaning behind the colon symbol that I didn't know?

For deleting remote branches, there's now a prettier syntax [`git push origin --delete foobar`](http://git-scm.com/book/ch3-5.html#Deleting-Remote-Branches) — quetzalcoatl, Nov 05 '15 at 13:56

score 106 · Accepted Answer · answered Sep 05 '11 at 03:41

106

It is not the meaning of the : per se, but what is present, or rather absent before it.

The refspec format is

<+><source>:<destination>

(optional + for non-fast forward)

So when you do something like git push origin :featureA, you are specifying an empty source ref and basically making the destination "empty" or deleting it.

PS: Note that the refspec of : or nothing doesn't mean push nothing to nothing however. It makes git to push "matching" branches: for every branch that exists on the local side, the remote side is updated if a branch of the same name already exists on the remote side.

answered Sep 05 '11 at 03:41

manojlds

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Git >=1.7.0 added `git push origin -d ` to delete and `git push origin -D ` to force delete a remote branch. – robsn May 10 '17 at 07:53
So when would you put something before the :? – ITIA Jul 12 '19 at 21:45
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@ITIA when your local branch has a different name than the remote one. – listerreg Feb 28 '20 at 15:30

score 34 · Answer 2 · edited Dec 18 '13 at 15:53

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The colon isn't a "delete flag". Note that git push and git pull both accept zero or more refspecs as their final argument(s). Now read about refspecs. A colon separates source from destination in a refspec. The command git push origin :foo has an empty source and essentially says "push nothing to branch foo of origin", or, in other words, "make branch foo on origin not exist".

edited Dec 18 '13 at 15:53

Andris

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answered Sep 05 '11 at 03:40

Ryan Stewart

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IMO, your answer doesn't answer the question for the following reason: if I try to push a branch whose history has diverged, I need to force push the branch. However, this is not the case when deleting a branch using `:foo`. An empty branch does not share history with an existing remote branch and so it cannot, the way I see it, overwrite an existing remote branch with an empty branch. Something feels wrong with your answer. – Umang Sep 05 '11 at 04:02
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@Umang: afaik, it's only a conceptual thing, and I didn't say "push an empty branch". I said "push nothing". I don't disagree with your assessment that it would make more sense with a "+" in front of it, but this is just how it works. See the [last section](http://progit.org/book/ch9-5.html#deleting_references) of the refspecs link I posted, and decide whether you trust the author. – Ryan Stewart Sep 05 '11 at 04:06
I think I understand a little better now. Thanks! – Umang Sep 05 '11 at 04:27

Why does Git use a colon (:) to delete remote branches?

2 Answers2

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