Mercurial, "Branching with bookmarks"

Question

I read this document: A Guide to Branching with Mercurial, specifically the section titled Branching with Bookmarks.

It says:

Now you’ve got two bookmarks (essentially a tag) for your two branches at the current changeset.

To switch to one of these branches you can use hg update feature to update to the tip changeset of that branch and mark yourself as working on that branch. When you commit, it will move the bookmark to the newly created changeset.

I tried this, but it ended up moving both bookmarks at the same time.

Is that guide wrong, outdated, or did I do something wrong? Note that I know that having bookmarks on separate branches only moves the bookmark related to the branch I'm currently working on, but that guide (which a lot of people says is the definite guide to this) specifically says the above text, which indicates that it should've worked by "telling" Mercurial which bookmark (branch) I'm working on.

Testing shows otherwise though.

Any ideas?

Example:

> hg init
> echo 1 >test.txt
> hg commit -m "initial" --addremove
adding test.txt

> hg bookmark main
> hg bookmark feature
> hg log
changeset:   0:c56ceb49ee20
tag:         feature
tag:         main
tag:         tip
user:        Lasse V. Karlsen <[email protected]>
date:        Tue Nov 30 23:06:16 2010 +0100
summary:     initial

> hg update feature
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

> echo 2 >test2.txt
> hg commit -m "feature 1" --addremove
adding test2.txt

> hg log
changeset:   1:9f2f5869b57b
tag:         feature                             <---- both were moved
tag:         main                                <----
tag:         tip
user:        Lasse V. Karlsen <[email protected]>
date:        Tue Nov 30 23:06:45 2010 +0100
summary:     feature 1

changeset:   0:c56ceb49ee20
user:        Lasse V. Karlsen <[email protected]>
date:        Tue Nov 30 23:06:16 2010 +0100
summary:     initial

Answer 1

If I got you right, you want only the bookmark you've updated to move on the next commit. For this purpose the bookmarks extensions has the track.current option.

From BookmarksExtension:

By default, when several bookmarks point to the same changeset, they will all move forward together. It is possible to obtain a more Git-like experience by adding the following configuration option to your .hgrc

[bookmarks]
track.current = True

In your example, this would keep the main bookmark at revision 0.

If the track.current option is enabled, the currently active bookmark is annotated with an asterisk in the output of hg bookmarks.

UPDATE: Since Mercurial 1.8 the default behavior is to only move the current bookmark, i.e. the above mentioned option is not needed anymore [1].

Answer 2

If you read the description of the BookmarksExtension, it says:

Bookmarks are references to commits that are automatically updated when new commits are made.

and:

Since bookmarks are automatically updated when commiting to the changeset they are pointing to, they are especially useful to keep track of different heads.

In your case, you only had one head in the repository at the time you created both bookmarks. If you use a sequence like the following, it should work as you expect:

hg init foo
# edit, edit, edit
hg commit -A -m "root"
hg bookmark main
# edit, edit, edit ...
hg commit -m "main 1"
hg update 0
# edit, edit edit
hg bookmark feature
hg commit -m "feature 1"