mercurial presentation: master blueprint v 7.0 - university of

ICOSST-2010, Dec 22-24, Lahore, Pakistan

Jamshaid Iqbal Janjua, Shahid Awan

[email protected]

[email protected]

M E R C U R I A L (The Source Control Management)

Al-Khawarizmi Institute of Computer Science

University of Engineering & Technology, Lahore, Pakistan.

Presented in Open Source Series Workshop 2010

22-24 December, 2010 © ICOSST 2010

mailto:[email protected]




Agenda

Introduction

Source Control Management

Mercurial

Basic Concepts

Branches

Merging

Changesets

Mercurial Features

Underlying Model

Talking to Other Systems

Third Party Tools

Demonstration



Source Control Management (SCM)

Source Control Management is the administrative

organization of Changes to Documents, Programs,

and Other information stored as computer files.

Also known as

Revision Control System (RCS)

Version Control System (VCS)



SCM :: Usage

Why is Source Control Management Needed ?

Avoid Manual Management (an error-prone task)

Tracks the History of the Project

Easy to Manage the Drift

Helps to Recover from Mistakes



SCM :: Options

Software Maintainer Development

Status

Repository

Model

License Cost

Mercurial Matt

Mackall

Actively

developed Distributed

GPL Free

SVN CollabNet,

Inc

Actively

developed

Client–

server

Apache/BSD

style

Free

Git Junio

Hamano

Actively

developed Distributed

GPL Free

CVS The CVS

Team

Maintained but

new features not

added

Client–

server

GPL Free

VSS Microsoft

Serious bug

fixes only

Shared

Folder

Proprietary Non -free



Knowing Mercurial …

Main Features

Free source control management tool & Easier to learn

Cross-platform, Fast, Distributed revision control system

Robust support for branching & merging

Scales to the demands of Real, Challenging environments

High performance & Extensible

Strong focus on back & forward Compatibility

New Clients can Read/Write all old formats on disk

Old clients can read/Write to all new Servers

Strong focus on Data Safety

Files are not overwritten, only appended to

Easier to recover from disk crashes

http:/

/ w

ww

.mercu

rial.se

lenic.co

m/



Why Distributed ?

Distributed SCM gives you:

Offline commits

Rich set of fast local operations

Derived effects

Fine file commits

Searchable history

Branching & Merging becomes a natural task

Enables better Work flows



Who is Using Mercurial ?

And Many Others …..



Mercurial Commands

Local Commands

hg commit : Save a snapshot into current repository

hg update : Checkout revision into working directory

hg merge : Join different lines of history

Network Commands

hg pull : Retrieve changesets from another repository

hg push : Send your changesets to another repository

Administrative Commands

hg clone : Copies or downloads a repository

hg add : Adds a file or directory to the local source tree

hg remove : Removes a file or directory from the local source



Key Concepts

Repository

A Remote Copy of Source Tree with Revision History.

Working Copy

Also known as working directory. It's the Top-level Directory in a repository, in which the plain

versions of files are available to read, edit and build.

Changeset

It's a Collection of all the Changes that lead to a new revision of the repository.

Hello.java

Makefile

commit

update

User A

push

pull



Mercurial Branches

A Key Concept

Parallel lines of development

Used to track releases

Used to isolate disruptive changes

1.0.1 1.0.2

1.0

1.0.1 1.0.2

1.0



Mercurial Merging

A Key Concept

Combines two branches

Used to merge back bug fixes

Used to integrate feature branches

1.0.1 1.0.2

1.0



Moving Changesets Around

0 A1 A2 A3

C1 0

B1 0

B1

C2

A1

C4

A2

C3

B1

A3

USER A USER B

USER C

pull



Distributed Revision Control

Mercurial duplicates the history on many servers

USER B USER C

USER A USER A’s

Laptop



Distributed Revision Control

Mercurial duplicates the history on many servers

USER B USER C

USER A USER A’s

Laptop

SERVER



Workflow In a Team

Mercurial scales from a single team ….

USER A

USER C

USER B

TEST

SERVER

PROD

SEVER



Workflow Between Company Divisions

…. to enterprise wide development ….

SITE A

SITE B

SITE C



Workflow Between Two Computers

…. to working with yourself

USER A USER B



The Underlying Model

A Mercurial changeset conceptually consists of:

0-2 parent changeset IDs

Root changeset has no parents

Normal changeset has one parents

Merge changeset has two parents

Date, username, commit message

Difference from first parent changeset

Changeset ID is computed as SHA-1 hash of above.



Migration

The convert extension in Mercurial can import history from

CVS, SVN, Git, Bazaar, Darcs, etc.

Incremental conversion

The hgsubversion extension in Mercurial let’s you:

Use hg clone on SVN Url

Use hg pull to convert new SVN revisions

Use hg push to commit changesets to SVN Server

Goal: make Mercurial a better Subversion client then SVN!



Third-Party Tools

Tools with Mercurial support:

Shell integration:

TortoiseHg(Windows, Mac, Linux)

IDEs: Eclipse, NetBeans, IntelliJ,

Visual Studio, Emacs

Project Support: Trac, JIRA,

Maven, Hudson, BuildBot

Ant tasks



Installation



Tortoise Overlay Icon Server



TortoiseHg Global Settings



D E M O N S T R A T I O N



Conclusion

Free source control management tool & Easier to Learn

Cross-platform, Fast, Distributed Revision Control system

Simple yet Strong Model for Branching & Merging

Scales to the demands of Real, Challenging Environments

Light Weight & High performance



Further Information

http://mercurial.selenic.com/

http://hgbook.red-bean.com

http://hginit.com

http://mercurial.selenic.com/wiki/Tutorial

http://www.mercurial.ch

http://jaoo.dk/dl/2009/Web/Mercurial.pdf

http://www.softwareprojects.com/resources/programming/t-

mercurial-version-control-1853.html



http://mercurial.selenic.com/wiki/Tutorial

Thank You!

