2010

The Subversion Dilemma !

Check in buggy code and drive everyone else crazy

Avoid checking it in until it’s fully debugged

or

The Subversion Dilemma !

Weeks without Version Control

Jens Schumacher – Atlassian What is DVCS and why it will change the way we work!

2010

Overview!

1.  Mercurial vs. Subversion

2.  Basic concepts

3.  Use cases

Subversion vs Mercurial!

Subversion vs Mercurial!

Merging

Subversion vs Mercurial!

Branching

Subversion vs Mercurial!

Repository Access

Subversion vs Mercurial!

Performance

Subversion vs Mercurial!

Sharing

Subversion vs Mercurial!

Tool Support

Subversion vs Mercurial!

Authentication

Subversion vs Mercurial!

Check Out

Subversion vs Mercurial!

Overview!

1.  Mercurial vs. Subversion

2.  Basic concepts

3.  Use cases

Repository Architecture!

Subversion!

Mercurial!

Subversion!

Revisions

Subversion is always linear

Mercurial!

Changesets

head

Each Changeset can have multiple children

Mercurial!

head

head

Mercurial!

Pull

Merge

Mercurial!

"hg commit" adds a new node

"hg push" and "hg pull" transfer nodes in the graph between two repositories

"hg merge" merge changes in a repository

Branching in Mercurial!

•  Forks"•  Named Branches"•  Bookmarks"•  Anonymous Branches"

Forks!

Forks!

•  Complete Isolation"•  Very easy to discard"

•  Forking is slower"

Disadvantages"Advantages"

1 2

Forks!

When to use Forks"

•  When you donʼt have commit access"•  To experiment"•  For a build repository"

Named Branches!

Named Branches!

•  Branch Metadata"•  Faster than Forking"

•  Branch Metadata"•  Closing a Branch

(fixed in 1.2)"

Disadvantages"Advantages"

Named Branches!

When to use Named Branches"

•  Working in a team on a feature"

Bookmarks!

Bookmarks!

•  Lightweight"•  Can be deleted"•  Similar to git"

•  Local (fixed in 1.6) "•  Possible loss of context "

Disadvantages"Advantages"

Bookmarks!

When to use Bookmarks"

•  Working in a team on a feature"•  If you like to way git does branching"•  If you use Mercurial 1.6"

Anonymous Branches!

Anonymous Branches!

•  Fast "•  No name required"•  No closing required"

•  No description"•  Changeset # required

(lookup with hg log)"

Disadvantages"Advantages"

Anonymous Branches!

When to use Anonymous Branches"

•  For quick & small fixes"

Overview!

1.  Mercurial vs. Subversion

2.  Basic concepts

3.  Use cases

BitBucket!

Mercurial code hosting"

•  Free for 5 users"•  Unlimited public collaborators"•  Unlimited disk space"

Getting Started!

The Basics!

hg init create a new repositoryhg commit save your changes in the current repositoryhg log see all changes in your repositoryhg pull pull all changes from another repository into yourshg push push your changes into another repositoryhg merge join different lines of history

hg update update the repository's working directoryhg help <command>

Separate Features!

Use Case Work on several features in parallel

Separate Features!

$ hg clone project feature$ cd feature$ (do some changes and commits)

Clone

Separate Features!

$ cd ../project$ hg incoming ../feature

Incoming

Use hg incoming --patch to view the diffs

Separate Features!

$ hg pull ../feature

Pull

The history of feature one is now in your project. However, changes are not yet visible and only stored in the .hg directory

Separate Features!

$ hg merge

Merge

$ hg commit(enter commit message)

Commit

Separate Features!

Changesets

Collaborative Feature Development!

Use Case Using Mercurial to help coordinate the coding

Collaborative Feature Development!

$ hg branch feature(do some changes)$ hg commit(write commit message)

Create a branch

$ hg update feature(do some changes)$ hg commit(write commit message)

Collaborative Feature Development!

$ hg update default$ hg merge feature$ hg commit(write commit message)

Merge the named branch

Named branches stay in history as permanent records after you finished your work.

Collaborative Feature Development!

Changesets

Tagging Revisions!

Use Case Release a plugin

Tagging Revisions!

$ hg tag -r 8 v0.1

Add a tag

$ hg tags

See all tags

$ hg update v0.1

Update to a tagged revision

Tagging Revisions!

Tags"

Overview!

1.  Mercurial vs. Subversion

2.  Basic concepts

3.  Use cases

Try BitBucket!

bitbucket.org"

Links!

•  http://mercurial.selenic.com"•  http://stevelosh.com/blog/2009/08/a-guide-to-

branching-in-mercurial"•  http://hgbook.red-bean.com/"

Thank you!!