Why do I need hg update after hg pull while in git I'm doing only git pull

Question

In git to pull and use the latest changes to my local repository I'm using git pull.

In hg, I also use hg pull but it prints then

run 'hg update' to get a working copy

I do run hg update but I wonder why is this difference from git?

Answer 1

The other answers don't actually answer the question, which is: why don't Git and Mercurial work the same? Is there a philosophical difference?

In Mercurial, pull is the opposite of push: it syncs the local repo with a remote repo without touching the working copy. So it's more consistent.

In Git, pull is a fetch plus a merge, or a pull plus an update in Mercurial terms. Usually this is what you want. So it's more efficient.

The Distributed Version Control University talk has a slide at the 4-minute mark that clearly demonstrates the way Mercurial works. Michael Ernst's Version control concepts and best practices has a similar diagram (included below):

Answer 2

Because git pull internally performs git fetch and git merge, whereas hg pull only does what git fetch does. Just do hg pull -u instead. See also this command equivalence table.

Git fetch and mercurial pull do the same thing. Mercurial fetch and git pull do the same thing.

Of course Mercurial and Git use different data structures internally, so at some point there is a technical difference in the implementation details. If you really care deeply about it, just compare the documentation for hg pull and git fetch. The Git wording is more technical and verbose, but in the end it is the same.