The document discusses distributed version control systems (DVCS) like Mercurial compared to centralized version control systems like Subversion. It covers basic DVCS concepts like repositories, changesets, branching and merging in Mercurial. It also provides examples of using Mercurial for separate feature development, collaborative feature development, and tagging revisions.

1. 2010

2. The Subversion Dilemma !
Check in buggy code and drive everyone else crazy
Avoid checking it in until it’s fully debugged
or

3. The Subversion Dilemma !
Weeks withoutVersion Control

4. Jens Schumacher – Atlassian
What is DVCS and why it will
change the way we work!
2010

5. Overview!
1. Mercurial vs. Subversion
2. Basic concepts
3. Use cases

7. Subversion vs Mercurial!

8. Subversion vs Mercurial!
Merging

9. Subversion vs Mercurial!
Branching

10. Subversion vs Mercurial!
Repository
Access

11. Subversion vs Mercurial!
Performance

12. Subversion vs Mercurial!
Sharing

13. Subversion vs Mercurial!
Tool Support

14. Subversion vs Mercurial!
Authentication

15. Subversion vs Mercurial!
Check Out

16. Subversion vs Mercurial!

17. Overview!
1. Mercurial vs. Subversion
2. Basic concepts
3. Use cases

18. Repository Architecture!

19. Subversion!

20. Mercurial!

21. Subversion!
Revisions
Subversion is always linear

22. Mercurial!
Changesets
head
Each Changeset can have multiple children

23. Mercurial!
head
head

24. Mercurial!
Pull
Merge

25. 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

26. Branching in Mercurial!
• Forks"
• Named Branches"
• Bookmarks"
• Anonymous Branches"

27. Forks!

28. Forks!
• Complete Isolation"
• Very easy to discard"
• Forking is slower"
Disadvantages"Advantages"
1 2

29. Forks!
When to use Forks"
• When you donʼt have commit access"
• To experiment"
• For a build repository"

30. Named Branches!

31. Named Branches!
• Branch Metadata"
• Faster than Forking"
• Branch Metadata"
• Closing a Branch
(fixed in 1.2)"
Disadvantages"Advantages"

32. Named Branches!
When to use Named Branches"
• Working in a team on a feature"

33. Bookmarks!

34. Bookmarks!
• Lightweight"
• Can be deleted"
• Similar to git"
• Local (fixed in 1.6) "
• Possible loss of context "
Disadvantages"Advantages"

35. 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"

36. Anonymous Branches!

37. Anonymous Branches!
• Fast "
• No name required"
• No closing required"
• No description"
• Changeset # required
(lookup with hg log)"
Disadvantages"Advantages"

38. Anonymous Branches!
When to use Anonymous Branches"
• For quick & small fixes"

39. Overview!
1. Mercurial vs. Subversion
2. Basic concepts
3. Use cases

40. BitBucket!
Mercurial code hosting"
• Free for 5 users"
• Unlimited public collaborators"
• Unlimited disk space"

41. Getting Started!

42. 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 di
rectoryhg help <command>

43. Separate Features!
Use Case
Work on several features in parallel

44. Separate Features!
$ hg clone project feature$ cd feature$
(do some changes and commits)
Clone

45. Separate Features!
$ cd ../project$ hg incoming ../feature
Incoming
Use hg incoming --patch to view the diffs

46. 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

47. Separate Features!
$ hg merge
Merge
$ hg commit(enter commit message)
Commit

48. Separate Features!
Changesets

49. Collaborative Feature Development!
Use Case
Using Mercurial to help coordinate the coding

50. 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)

51. 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.

52. Collaborative Feature Development!
Changesets

53. Tagging Revisions!
Use Case
Release a plugin

54. 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

55. Tagging Revisions!
Tags"

56. Overview!
1. Mercurial vs. Subversion
2. Basic concepts
3. Use cases

57. Try BitBucket!
bitbucket.org"

58. Links!
• http://mercurial.selenic.com"
• http://stevelosh.com/blog/2009/08/a-guide-to-
branching-in-mercurial"
• http://hgbook.red-bean.com/"

59. Thank you!!