Difference between revisions of "Version Control"

Revision as of 23:46, 20 November 2011

The Dreamwidth code uses a Mercurial repository. However, it also uses code that uses different repository systems like Subversion. (If you aren't familiar with repositories, here's a good intro.)

There are currently two separate strategies for editing code, Working with $LJHOME/bin/cvsreport.pl and Using Mercurial.

Checking out the code

Get the bootstrap script that downloads all of the code:

wget http://hg.dwscoalition.org/dw-free/raw-file/tip/bin/bootstrap.pl

If your $LJHOME environment variable is set up (see Dreamwidth Scratch Installation for more information on this), run the script:

perl bootstrap.pl

Checking out all the various packages and repositories will take some time. Afterwards, you can delete the bootstrap script:

rm bootstrap.pl

Working with $LJHOME/bin/cvsreport.pl

The workhorse that ties all the version control systems of all the code bases together is $LJHOME/bin/cvsreport.pl. With it, you can update to new versions and track changes.

Here is a list of the options that come up with bin/cvsreport.pl -help:

--help          Get this help
--sync          Put files where they need to go.
                All files, unless you specify which ones.
--diff          Show diffs of changed files.
--cvsonly       Don't consider files changed in live dirs.
--liveonly      Don't consider files changed in the CVS dirs.
--init          Copy all files from cvs to main, unconditionally.
--update        Updates files in the CVS dirs from the cvs repositories.
--justfiles -1  Only output files, not the old -> new arrow. (good for xargs)
--livelist -ll  Output the list of all accounted-for files.
--which         Output the source of the given file
--these -t      Refuse to --sync if no files are specified.
--map           Like --livelist and --which combined.
--all           Overrides --these, allowing --sync to run with no args.
--print-current-branches -pcb    Print repositories and their current branches
--print-branches -pb     Print repositories and their branches.
--print-repos -pr        Print repositories and their resource URLs.
--print-vars -pv         Print configuration variables specified in .conf files.
--no-space-changes -b    Do not display whitespace differences.

Updating to the latest code

See the Dev Maintenance article for instructions on this.

Displaying code changes

This will show all the changes you've made to the code:

$LJHOME/bin/cvsreport.pl -diff

You can make a patch by directing this output to a file (see Dev Patches for more information on patches):

$LJHOME/bin/cvsreport.pl -diff > PATCHFILE.

Suggested patchfile name should be something along the lines of bug#_desc.patch, like bug56_titlefix.patch.

Reverting changes

There is unfortunately no .$LJHOME/bin/cvsreport.pl -revert. One way to revert changes is to delete the file with the changes from the live code and then run:

$LJHOME/bin/cvsreport.pl -sync -cvsonly

Using Mercurial

Mercurial Queues

Mercurial queues is a feature for managing commits as a series of patches. It's good for making local changes that are meant to be temporary, like patches you are working on before submitting them to review/commit. Instead of mixing your commits with the official ones, you can have a series, or queue, of patches which can be applied or unapplied at any time. It's also useful when you're going through files implementing a new feature. While you're doing that, you see typos, bugs, or missing/misleading comments and you need to sort your changes by type.

This is useful to make a convient updatable workflow: apply your patches while you are working, unapply before you grab the latest changes to prevent conflict, merge in the updates, then apply your patches again.

When you are working with an MQ system, you will be making changes to the code in the $LJHOME/cvs/dw-free directory. To apply and test those changes to the live code, you will need to use $LJHOME/bin/cvsreport.pl to sync. An easy way to do this is to make an alias dwsync command:

alias dwsync="$LJHOME/bin/cvsreport.pl --sync --cvsonly"

Starting out

Check that mercurial queues are enabled on your system with:

hg help

There should be a section of commands that start with q.

If not, you'll have to add this to a file at ~/.hgrc:

[extensions]
hgext.mq =

You might also want to add a username to that file:

[ui]
username = foxfirefey <skittisheclipse@gmail.com>

To set up MQ for Dreamwidth code, first create a repository to store and keep track of your patches:

cd $LJHOME/cvs/dw-free
hg qinit -c

Working with patches

To start out with, make sure you are in dw-free:

cd $LJHOME/cvs/dw-free

Make sure you have no outstanding changes. You can check that you are working with a clean checkout by using hg diff and use hg revert --all to get there if you're willing to lose all the current changes.

To make a new patch, use the command: (Do this before you start making the changes!)

hg qnew PATCHNAME

If part of your patch involves creating new files, identify the new files for Mercurial:

hg add relative/path/to/NEWFILE relative/path/to/NEWFILE1 relative/path/to/NEWFILE2…

To see what patch is currently on top:

hg qtop

To add changes to a patch, edit a file and do:

hg qrefresh

This updates your patch with all your changes. You can change the "commit" message on a patch at the same time you use qrefresh. To see what changes your patch has, use:

hg export qtip

To see what changes you have made that aren't saved in a patch:

hg diff

To see what changes your patches has, plus all changes that aren't saved in a patch:

hg qdiff

Applying and unapplying patches

Patches are a stack of patches. Using hg qnew to create a new patch will place it on the top of the stack. You can unapply the patch at the top of the stack (and remove it from the stack) using hg qpop, and apply a patch with hg qpush.

See also: Dev Patches

Updating your code

Add this alias to your ~/.bash_profile and source ~/.bashprofile:

alias dwupdate='hg -R $LJHOME/cvs/dw-free qpop -a && \
  hg -R $LJHOME/cvs/dw-free update && \
  hg -R $LJHOME/cvs/dw-free qpush -a'

See Dev Maintenance for more details.

Making a patchfile

You can also use qdiff to make a patch file:

hg qdiff > PATCHFILE

Suggested patchfile name should be something along the lines of bug#_desc.patch, like bug56_titlefix.patch.

Further MQ References

• Managing change with Mercurial Queues
• Mercurial Queues

Committing changes

Only xb95 and a few other developers can do this.

For details, see Dev Committing Guidelines