2.1   How can I become a developer?

One way to become a developer is through the School of Hard Knocks.

Otherwise just contribute on a regular basis through patches and just ask for commit privileges once you have helped out enough that other developers tire of doing commits for you.

3.1   Where can I learn about Subversion (svn)?

Subversion has its official web site at http://subversion.tigris.org/ (it is also known as svn thanks to that being the name of the executable of Subversion itself). A book on Subversion published by O'Reilly Media, Version Control with Subversion, is available for free online.

With Subversion installed, you can run the help tool that comes with Subversion to get help:

svn help

This will give you the needed information to use the tool. The man page for svn is rather scant and thus not worth reading.

3.2   What do I need to use Subversion?

[tunnels]
ssh="c:/path/to/putty/plink.exe" -T

3.3   How do I get a checkout of the repository (read-only and read-write)?

Regardless of whether you are checking out a read-only or read-write version of the repository, the basic command is the same:

svn checkout <URL> [PATH]

<URL> is the specified location of the project within the repository that you would like to check out (those paths are discussed later). The optional [PATH] argument specifies the local directory to put the checkout into. If left out then the tail part of <URL> is used for the directory name.

For a read-only checkout, the format of <URL> is:

http://svn.python.org/projects/<path>

with <path> representing the path to the project. A list of projects can be viewed at http://svn.python.org/view/ . Do note that any subdirectory may also be checked out individually.

For a read-write checkout (with a caveat for Windows users using PuTTY without Pageant), the format for <URL> is:

svn+ssh://pythondev@svn.python.org/<path>

There are three critical differences between a read-only URL and a read-write URL. One is the protocol being specified as svn+ssh and not http. Next, notice the addition of the username pythondev (note that for Windows users using PuTTY without Pageant should leave off pythondev@ if PuTTY was set up following the instructions in this FAQ). Lastly, note that projects was removed from the path entirely for a read-write checkout.

The Subversion repository has many projects under it. Most people are probably interested in one of these three projects:

• the trunk or HEAD (the current version under development)
• the latest release (plus bug fixes) of Python (e.g., 2.5)
• the PEPs (Python Enhancement Proposals)

A read-only checkout of the three projects above can be checked out using the following <URL> paths, respectively:

• http://svn.python.org/projects/python/trunk
• http://svn.python.org/projects/python/branches/release25-maint
• http://svn.python.org/projects/peps/trunk

For read-write checkouts (which require that you have commit privileges), the URLs for the same projects are:

• svn+ssh://pythondev@svn.python.org/python/trunk
• svn+ssh://pythondev@svn.python.org/python/branches/release25-maint
• svn+ssh://pythondev@svn.python.org/peps/trunk

3.4   How do I update my working copy to be in sync with the repository?

Run:

svn update

from the directory you wish to update (and all subdirectories).

3.5   How do I browse the source code through a web browser?

Visit http://svn.python.org/view/ to browse the Subversion repository.

3.6   Where can I find a downloadable snapshot of the source code?

Visit http://svn.python.org/snapshots/ to download a tarball containing a daily snapshot of the repository.

3.7   Who has commit privileges on the Subversion repository?

See http://www.python.org/dev/committers for a list of committers.

3.8   How do I get commit privileges on the svn repository if I had the same privileges on the CVS repository?

If you have established commit privileges as listed at http://sourceforge.net/project/memberlist.php?group_id=5470 but do not have them yet for the Subversion repository, then there are a few steps you must take:

1. Generate an SSH 2 public key
2. Email key and name (first and last required, middle optional)
3. Wait for verification email that the key has been installed
4. Verify access

3.9   How do I verify that my commit privileges are working?

ssh pythondev@svn.python.org

( success ( 1 2 ( ANONYMOUS EXTERNAL ) ( edit-pipeline ) ) )

c:\path\to\putty\plink.exe pythondev@svn.python.org

( success ( 1 2 ( ANONYMOUS EXTERNAL ) ( edit-pipeline ) ) )

3.10   What configuration settings should I use?

Make sure the following settings are in your Subversion config file (~/.subversion/config under UNIX):

[miscellany]
enable-auto-props = yes

[auto-props]
* = svn:eol-style=native
*.c = svn:keywords=Id
*.h = svn:keywords=Id
*.py = svn:keywords=Id
*.txt = svn:keywords=Author Date Id Revision

The [auto-props] line specifies the beginning of the section in the config file. The svn:eol-style setting tells Subversion to check out files using the native line endings on your OS. It will also automatically convert line endings upon committal so that they are consistent across all platforms. The svn:keywords settings are to automatically substitute $keyword$ arguments in files that match the pattern. *.txt has more options so as to cover all needed keywords for PEPs.

The [miscellany] section and its one option make Subversion apply the various rules in the [auto-props] section automatically to all added or imported files into the respository.

3.11   How do I add a file or directory to the repository?

Simply specify the path to the file or directory to add and run:

svn add PATH

Subversion will skip any directories it already knows about. But if you want new files that exist in any directories specified in PATH, specify --force and Subversion will check all directories for new files.

You will then need to run svn commit (as discussed in How do I commit a change to a file?) to commit the file to the repository.

3.12   How do I commit a change to a file?

To have any changes to a file (which include adding a new file or deleting an existing one), you use the command:

svn commit [PATH]

Although [PATH] is optional, if PATH is omitted all changes in your local copy will be committed to the repository. DO NOT USE THIS!!! You should specify the specific files to be committed unless you are absolutely positive that all outstanding modifications are meant to go in this commit.

To abort a commit that you are in the middle of, perform a commit with no message (i.e., close the text editor without adding any text for the message). Subversion will ask if you want to abort the commit or not at that point.

If you do not like the default text editor Subversion uses for entering commmit messages, you may specify a different editor in your Subversion config file with the editor-cmd option in the [helpers] section.

3.13   How do I delete a file or directory in the repository?

Specify the path to be removed with:

svn delete PATH

Any modified files or files that are not checked in will not be deleted in the working copy on your machine.

3.14   What files are modified locally in my working copy?

Running:

svn status [PATH]

will list any differences between your working copy and the repository. Some key indicators that can appear in the first column of output are:

3.15   How do I find out what Subversions properties are set for a file or directory?

svn proplist PATH

3.16   How do I revert a file I have modified back to the version in the respository?

Running:

svn revert PATH

will change PATH to match the version in the repository, throwing away any changes you made locally. If you run:

svn revert -R

from the root of your local repository it will recursively restore everything to match up with the main server.

3.17   How do I find out who edited or what revision changed a line last?

You want:

svn blame PATH

This will output to stdout every line of the file along with what revision number last touched that line and who committed that revision. Since it is printed to stdout, you probably want to pipe the output to a pager:

svn blame PATH | less

3.18   How can I see a list of log messages for a file or specific revision?

To see the log messages for a specific file, run:

svn log PATH

That will list all messages that pertain to the file specified in PATH.

If you want to view the log message for a specific revision, run:

svn log --verbose -r REV

With REV substituted with the revision number. The --verbose flag should be used to get a listing of all files modified in that revision.

3.19   How can I edit the log message of a committed revision?

Use:

svn propedit -r <revision> --revprop svn:log

Replace <revision> with the revision number of the commit whose log message you wish to change.

3.20   How do I get a diff between the repository and my working copy for a file?

The diff between your working copy and what is in the repository can be had with:

svn diff PATH

This will work off the current revision in the repository. To diff your working copy with a specific revision, do:

svn diff -r REV PATH

Finally, to generate a diff between two specific revisions, use:

svn diff -r REV1:REV2 PATH

Notice the : between REV1 and REV2.

3.21   How do I undo the changes made in a recent committal?

Assuming your bad revision is NEW and OLD is the equivalent of NEW - 1, then run:

svn merge -r NEW:OLD PATH

This will revert all files back to their state in revision OLD. The reason that OLD is just NEW - 1 is you do not want files to be accidentally reverted to a state older than your changes, just to the point prior.

Note: PATH here refers to the top of the checked out repository, not the full pathname to a file. PATH can refer to a different branch when merging from the head, but it must still be the top and not an individual file or subdirectory.

3.22   How do I update to a specific release tag?

Run:

svn list svn+ssh://pythondev@svn.python.org/python/tags

or visit:

http://svn.python.org/view/python/tags/

to get a list of tags. To switch your current sandbox to a specific tag, run:

svn switch svn+ssh://pythondev@svn.python.org/python/tags/r242

To just update to the revision corresponding to that tag without changing the metadata for the repository, note the revision number corresponding to the tag of interest and update to it, e.g.:

svn update -r 39619

What you probably want though, is the switch that sandbox to the tag's url:

svn switch svn+ssh://pythondev@svn.python.org/python/tags/r242

3.23   Why should I use svn switch?

I found this small treatise by Giovanni Bajo in python-dev on the svn switch command helpful:

If you realize that each file/directory in Subversion is uniquely identified by a 2-space coordinate system [URL, revision] (given a checkout, you can use "svn info" to get its coordinates), then we can say that "svn up -r N" (for some revision number N) keeps the url unchanged and changes the revision to whatever number you specified. In other words, you get the state of the working copy URL at the time revision N was created. For instance, if you execute it with revision 39619 within the trunk working copy, you will get the trunk at the moment 2.4.2 was released.

On the other hand, "svn switch" moves the URL: it basically "moves" your checkout from [old_URL, revision] to [new_URL, HEAD], downloading the minimal set of diffs to do so. If the new_URL is a tag URL (e.g. .../tags/r242), it means any revision is good, since nobody is going to commit into that directory (it will stay unchanged forever). So [/tags/r242, HEAD] is the same as any other [/tags/r242, revision] (assuming of course that /tags/r242 was already created at the time the revision was created).

If you want to create a sandbox corresponding to a particular release tag, use svn switch to switch to [/tags/some_tag, HEAD] if you don't plan on doing modifications. On the other hand if you want to make modifications to a particular release branch, use svn switch to change to [/branches/some_branch, HEAD].

3.24   How do I create a branch?

The best way is to do a server-side copy by specifying the URL for the source of the branch, and the eventual destination URL for the new branch:

svn copy SRC_URL DEST_URL

You can then checkout your branch as normal. You will want to prepare your branch for future merging from the source branch so as to keep them in sync. To find out how to do that, read `How do I merge branches?`_.

3.25   How do I merge between branches?

First, you need svnmerge.py. Then you need to initialize the branch by having svnmerge.py discover the revision number that the branch was created with. Do this with the command:

svnmerge.py init

Then check in the change to the root of the branch. This is a one-time operation.

When you want to merge from the branch you branched off of, you execute the command:

svnmerge.py merge

All revisions that apply to your branch will be applied to your branch. If there are conflicts they need to be resolved. Once that has been done, check in the changes created by the merge.

To commit the branch, you can use the generated commit message, e.g.:

svn ci -F svnmerge-commit-message.txt
rm svnmerge-commit-message.txt

3.26   How do I block a specific revision from being merged into a branch?

With the revision number that you want to block handy and svnmerge.py, go to your checkout of the branch where you want to block the revision and run:

svnmerge.py block -r <revision #>

This will modify the repository's top directory (which should be your current directory) and create svnmerge-commit-message.txt which contains a generated log message.

If the command says "no available revisions to block", then it means someone already merged the revision.

To check in the new metadata, run:

svn ci -F svnmerge-commit-message.txt

3.27   How do I include an external svn repository (external definition) in the repository?

Before attempting to include an external svn repository into Python's repository, it is important to realize that you can only include directories, not individual files.

To include a directory of an external definition (external svn repository) as a directory you need to edit the svn:externals property on the root of the repository you are working with using the format of:

local_directory remote_repositories_http_address

For instance, to include Python's sandbox repository in the 'sandbox' directory of your repository, run svn propedit svn:externals . while in the root of your repository and enter:

sandbox http://svn.python.org/projects/sandbox/trunk/

in your text editor. The next time you run svn update it will pull in the external definition.

3.28   How can I create a directory in the sandbox?

Assuming you have commit privileges and you do not already have a complete checkout of the sandbox itself, the easiest way is to use svn's mkdir command:

svn mkdir svn+ssh://pythondev@svn.python.org/sandbox/trunk/<directory>

That command will create the new directory on the server. To gain access to the new directory you then checkout it out (substitute mkdir in the command above with checkout).

If you already have a complete checkout of the sandbox then you can just use svn mkdir on a local directory name and check in the new directory itself.

4.1   How do I generate an SSH 2 public key?

ssh-keygen -t dsa

4.2   Is there a way to prevent from having to enter my password for my SSH 2 public key constantly?

4.3   Can I make check-ins from machines other than the one I generated the keys on?

Yes, all you need is to make sure that the machine you want to check in code from has both the public and private keys in the standard place that ssh will look for them (i.e. ~/.ssh on Unix machines). Please note that although the key file ending in .pub contains your user name and machine name in it, that information is not used by the verification process, therefore these key files can be moved to a different computer and used for verification. Please guard your keys and never share your private key with anyone. If you lose the media on which your keys are stored or the machine on which your keys are stored, be sure to report this to pydotorg@python.org at the same time that you change your keys.

5.1   How to make a patch?

If you are using subversion (anonymous or developer) you can use subversion to make the patches for you. Just edit your local copy and enter the following command:

svn diff | tee ~/name_of_the_patch.diff

Else you can use the diff util which comes with most operating systems (a Windows version is available as part of the cygwin tools).

5.2   How do I apply a patch?

For the general case, to apply a patch go to the directory that the patch was created from (usually /dist/src/) and run:

patch -p0 < name_of_the_patch.diff

The -p option specifies the number of directory separators ("/" in the case of UNIX) to remove from the paths of the files in the patch. -p0 leaves the paths alone.

5.3   How do I undo an applied patch?

Undoing a patch differs from applying one by only a command-line option:

patch -R -p0 < name_of_the_patch.diff

Another option is to have 'patch' create backups of all files by using the -b command-line option. See the man page for 'patch' on the details of use.

5.4   How to submit a patch?

Please consult the patch submission guidelines at http://www.python.org/patches/ .

5.5   How to test a patch?

Start by testing on your own system. Python comes with an extensive regression test suite by running the Lib/test/regrtest.py script. For more thorough documentation, read the documentation for the test package at http://www.python.org/doc/lib/module-test.html.

If you suspect the patch may impact other operating systems, test as many as you have easy access to. You can get help on alternate platforms by contacting the people listed on http://www.python.org/moin/PythonTesters, who have volunteered to support a particular operating system.

5.6   How to change the status of a patch?

To change the status of a patch or assign it to somebody else you have to be a) a SourceForge-recognized Python developer and b) a patch administrator. Unfortunately the SourceForge default for developers is not to be patch administrators. Contact one of the project administrators if the following does not work for you.

Click on the patch itself. In the screen that comes up, there is a drop-box for "Assigned To:" and a drop-box for "Status:" where you can select a new responsible developer or a new status respectively. After selecting the appropriate victim and status, hit the "Submit Changes" button at the bottom of the page.

Note: If you are sure that you have the right permissions and a drop-box does not appear, check that you are actually logged in to SourceForge!

For more information about the use of the "Status:" and "Assigned To:" fields consult the Patch Manager Guidelines; A recent copy can be found in the Appendix of this FAQ.

6.1   Where can I submit/view bugs for Python?

The Python project uses Roundup for bug tracking. Go to http://bugs.python.org/ for all bug management needs. You will need to create a Roundup account for yourself before submitting the first bug report; anonymous reports have been disabled since it was too difficult to get in contact with submitters. If you previously had used SourceForge to report Python bugs, you can use Roundup's "Lost your login?" link to obtain your Roundup password.

6.2   How do I use the sourceforge bug manager?

By default, you will see the list of all Open bugs. You can change which bugs you're viewing by selecting the assigned_to/status/area/type select boxes.

To submit a bug, use the "Submit a Bug" link, near the top of the page.

7.1   Patch Manager Guidelines

Intended use of SourceForge patch Resolution, Status & "Assigned To" fields Revision 4 16-Mar-2001

In general, the Resolution and Status fields should be close to self-explanatory, and the "Assigned to:" field should be the person responsible for taking the next step in the patch process. Both fields are expected to change value over the life of a patch; the normal workflow is detailed below.

When you've got the time and the ability, feel free to move any patch that catches your eye along, whether or not it's been assigned to you. And if you're assigned to a patch but aren't going to take reasonably quick action (for whatever reason), please assign it to someone else ASAP: at those times you can't actively help, actively get out of the way.

If you're an expert in some area and know that a patch in that area is both needed and non-controversial, just commit your changes directly -- no need then to get the patch mechanism involved in it.

You should add a comment to every patch assigned to you at least once a week, if only to say that you realize it's still on your plate. This rule is meant to force your attention periodically: patches get harder & harder to deal with the longer they sit.