Transcript "SVN Commit" to - ics-software-engineering

Introduction to
Subversion (SVN)
and
Google Project Hosting
Philip Johnson
Collaborative Software Development Laboratory
Information and Computer Sciences
University of Hawaii
Honolulu HI 96822
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Basic concepts
SVN uses a centralized repository.
•We will not cover repository administration.
•Clients connect to a repository to download
working copies.
Working copies:
•Ordinary directory trees.
•Contains your files plus administrative files
in special subdirectories named '.svn'.
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Updates, Commits, Revisions
Working copy:
• A local directory tree
Commit:
• Upload your working copy to the SVN server.
• Creates a new repository-wide "revision", or
snapshot of the state of the repository.
Update:
• Make some or all of your working copy consistent
with a given revision.
• You can update to the
-latest revision
-any prior revision
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Review: Versions/Configurations
for RCS/CVS style CM
Foo.java
(1.1)
Foo.java
(1.2)
Foo.java
(1.3)
Foo.java
(1.2.1)
Bar.java
(1.1)
1.0.0
Foo.java
(1.4)
Foo.java
(1.2.2)
Bar.java
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1.0.1
Each file has its own version number.
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Foo.java
(1.5)
Bar.java
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1.1.0
SVN has repository-wide revisions
Each time you commit, you 'stamp' not the files you
commit with a new version, but the entire repository.
Foo.java
Foo.java
Bar.java
Bar.java
1
Foo.java
Foo.java
Bar.java
Bar.java
2
Foo.java
3
Bar.java
4
File changes color to indicate changed contents, but
Subversion doesn’t maintain a file-based “version number”.
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"Copying" in SVN is cheap
The database backend in SVN means that you
can make "copies" of an SVN directory
structure very cheaply.
•No files are physically copied, just pointers
to the files and info on which revision.
This means that you create branches, tags,
and the "trunk" by creating and merging
directories that each contain an entire "copy"
of an arbitrary number of files.
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Trunk, Branches, Tags
SVN project directories are structured by convention with
three top-level directories:
trunk/
• Represents the 'main line' of development with an entire
copy of the project.
branches/
• Contains subdirectories, each holding an entire copy of
the project.
• Each branch constitutes a significant enhancement to the
project that can be worked on independently.
tags/
• Contains subdirectories, each containing one snapshot of
the project.
• Each snapshot represents a "public release" or other
archival configuration of the project.
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Example
<repository>/stack/
trunk/
build.xml
src/
:
tags/
release-1.0/
build.xml
src/
:
branches/
add-generics/
build.xml
src/
:
add-intstack/
build.xml
src/
:
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Trunk vs. Branch
Trunk represents "gold" version of system
• Should always compile, always pass tests.
• In 413, this means passing the “verify” target!
Branches represent "temporary" development streams to
implement significant new features.
• Allow commits to repository without breaking the "gold"
version in the trunk.
• Branches don't need to always compile, pass tests.
You must "merge" a branch back into the trunk when
completed.
• Or at intermediate points when branch is "stable".
• The longer you wait to merge, the more difficult the
merge might be.
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Our SVN server: Google
Google provides a free service for hosting
open source projects. Includes:
•SVN server
•Mailing lists
•Issue tracker
We will use Google Project Hosting this
semester for all class projects.
Also good choice for hosting your future open
source projects!
•Alternatives: SourceForge, Java.net
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Local SVN Client Choices
Upcoming examples of local workspace
manipulation use TortoiseSVN client program.
•Best choice for Windows.
Other clients exist for other platforms
•http://subversion.tigris.org/links.html
For Mac I use:
•SmartSVN
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Google Project Hosting
Home: http://code.google.com/hosting/
Docs: http://code.google.com/hosting/faq.html
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Google Project Hosting/SVN
Use Cases
A. Basic Project source download
B. Basic daily activities when working with a
Project.
C. Merge conflicts
D. Defining a new Project
E. Beyond basic usage
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A. Basic Project source download
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A. Steps
Preconditions:
•Obtain the URL for the project.
•Obtain membership in project.
•Get your SVN password.
Setup local folder to hold project contents.
SVN 'checkout' the 'trunk' to your folder.
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A1. Find Project URL
You should be listed as a member or owner.
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A2. Find your SVN password
Only owners/members have a password.
•Allows commit (write) access.
Don’t worry, I’ve changed this.
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A3. Create local folder to hold the
sources
Example: c:\svn-google\stack-johnson
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A4. SVN 'checkout' project to
download sources
https://<project>.googlecode.com/svn/trunk
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https vs. http
The most common beginner mistake is to
check out the project using http, not https.
You can check out any Google project using
http, whether or not you are a member, but
you cannot commit any changes (even if you
are a member).
If you mistakenly check it out using http,
then delete your local directory and start
over using https.
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B. Basic daily activities when
working with a Project
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B. Steps
1. Update:
• "SVN Update" to make your local workspace consistent with
latest version from repository.
2. Run "verify" target
• Make sure your updated local version is running correctly.
3. Edit:
• Make improvements to the Project files.
4. Run "verify" target
• Make sure system works correctly before committing!
3. Commit:
• "SVN Commit" to 'publish' your improvements to the
repository.
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B1. SVN 'Update'
By default, makes your local workspace consistent
with the 'head' revision of the 'trunk' in the
repository.
•Right-click project folder, select SVN Update
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B2. Run "verify"
Ensure you're starting with a working version!
If verify target fails:
• contact your team members!
• check the project discussion list to see who committed!
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B3. Edit files, improve project
Locally modified files shown with red !
So are parent directories.
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B4. Run "verify"
Never commit changes that don't pass verify to
trunk!
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B5. Publish changes with SVN Commit
Select individual files or simply project
folder.
Right-click, select "SVN Commit"
Provide informative commit message.
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Informative Commit Messages
Informative commit messages indicate:
•What you did.
•Why you did it.
•What Google Issue is being addressed by
this commit (if any).
Examples of uninformative commit message:
•“Fixed bugs.”
•“”
Your commit messages will be posted to your
project’s discussion list, and so are easily
accessable for review.
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C. Merge conflicts
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C. Steps
Sometimes your "SVN commit" will fail
•Someone else committed changes to the
same lines that you modified after the time
you last updated your local copy.
To fix:
•Do "SVN Update" to "merge" the other
person's commit into your local copy.
•Make changes to make project consistent.
•Do "SVN Commit" to commit the new
version.
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D. Defining a new project
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D. Steps
1. Define the new project with Google Project Hosting.
• Define initial members.
• Set up mailing lists in google groups.
-Add [email protected] as a member.
• Get your SVN password.
2. Populate the SVN repository
• Checkout the 'trunk' directory to a newly created local
directory called something like “stack-johnson”.
• Add project files/directories to that directory.
• SVN 'add' those files.
• SVN 'commit' those files.
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D1. Creating a repository
We will use Google Projects to hold our course
projects this semester.
•Offers an SVN repository
•Also issue tracking, mailing lists, home page.
You must have a GMail account in order to create a
Google Project and be signed in.
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http://code.google.com/hosting
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D2. Create new project
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Project creation confirmation
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D3. Create <project>-discuss
discussion list
Use google groups interface for this.
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Set up discussion list
Add [email protected]
Also add all other project members.
Make group publicly visible; members by invite
only.
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D4. Add list to Project
Send commits and issues to project automatically to
the discussion list.
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D5. Add owners and members
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D6. SVN repository auto-created
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Google has a browse mode
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And can list changes
Bad!
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trunk/, branches/, tags/
subdirectories automatically created
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D7. Find subversion password
Only project owners and members get a password.
•Passwords allow "commit" (write) access.
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D8. Set up your local workspace
1. Create a folder to hold your project:
•Example: c:\svn-google\stack-johnson
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Setting up your local workspace
2. Right-click project folder, select "SVN Checkout".
• Enter https://<project>.googlecode.com/svn/trunk
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Setting up your local workspace
3. Enter your gmail account and SVN password
to authenticate yourself to the server.
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Setting up your local workspace
This folder is now a replication of the (empty)
"trunk" directory for this project.
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D9. Populate the trunk
directory with your project
Don't include the build or bin directories!
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SVN 'Add' your files/directories
1. Don't select the .svn directory!
2. Right-click selected file, select TortoiseSVN | Add
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SVN 'Commit' your files
1. Red ! means directory modified, not committed.
2. Right-click project folder, select SVN Commit
3. Enter informative log message.
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Files are now in repository
And email sent to stack-johnson-discuss group.
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E. Beyond basic usage
SVN has many other useful features:
•Using branches to isolate development
-Most complex part of SVN usage.
•SVN Blame
-Show who committed last version of each
line in the file.
•SVN Switch
-Move between trunk, branches, tags.
These will be covered later as need arises.
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Beginning SVN
Basic skills:
•Checkout existing project, modify, commit.
•Create new project.
•Resolve merge conflicts
Process simplifications:
•Commit all changes to "trunk".
•Never commit if 'verify' doesn't pass.
You can go very far and very fast with only
"beginner" skills!
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