Difference between revisions of "How to submit patches"

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(Make a patch: Fix git send-email example to use "criu-dev" instead of "master" branch)
 
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{{DISPLAYTITLE:How to submit patches into the CRIU}}
+
== Set up working environment ==
  
=Obtaining the source code=
+
Although criu could be run as non-root (see [[Security]]), development is better to be done as root. For example, some tests require root. So, it would be a good idea to set up some recent Linux distro on a virtual machine.
  
The CRIU sources are tracked by Git SCM at http://git.criu.org
+
== Get the source code ==
repository. You either could download packed sources or use git
 
tool itself.
 
  
For example to clone crtools one need to type
+
The CRIU sources are tracked by Git. Official CRIU repo is at [https://github.com/checkpoint-restore/criu https://github.com/checkpoint-restore/criu].
  
        git clone git://git.criu.org/crtools.git
+
The repository may contain multiple branches. Development happens in the '''criu-dev''' branch.
  
=Changing the source code=
+
To clone CRIU repo and switch to the proper branch, run:
  
When you change the source code keep in mind -- we prefer tabs and
+
<pre><nowiki>
indentations to be 8 characters width.
+
        git clone https://github.com/checkpoint-restore/criu criu
 +
        cd criu
 +
        git checkout criu-dev
 +
</nowiki></pre>
  
Other "rules" could be learned from the source code -- just make your code
+
== Compile ==
to look similar.
 
  
=Producing a patch=
+
First, you need to install compile-time dependencies. Check [[Installation#Dependencies]] for more info.
  
There are at least two ways to make it right.
+
To compile CRIU, run:
  
1) git format-patch
+
        make
  
You might need to read documentation on Git SCM how to prepare patch
+
This should create the <code>./criu/criu</code> executable.
for mail submission. Take a look on http://book.git-scm.com/ and/or
+
 
 +
== Edit the source code ==
 +
 
 +
If you use ctags, you can generate the ctags file by running
 +
 
 +
        make tags
 +
 
 +
When you change the source code, please keep in mind the following code conventions:
 +
 
 +
* we prefer tabs and indentations to be 8 characters width
 +
* consider reading [https://www.kernel.org/doc/Documentation/process/coding-style.rst Linux kernel coding style].
 +
 
 +
Other conventions can be learned from the source code itself. In short, make sure your new code
 +
looks similar to what is already there.
 +
 
 +
== Test your changes ==
 +
 
 +
CRIU comes with an extensive test suite. To check whether your changes introduce any regressions, run
 +
 
 +
        make test
 +
 
 +
The command runs [[ZDTM Test Suite]]. Check for any error messages produced by it.
 +
 
 +
In case you'd rather have someone else run the tests, you can use travis-ci for your
 +
own github fork of CRIU. It will check the compilation for various supported platforms,
 +
as well as run most of the tests from the suite. See https://travis-ci.org/checkpoint-restore/criu
 +
for more details.
 +
 
 +
== Make a patch ==
 +
 
 +
To create a patch, run
 +
 
 +
    git format-patch --signoff origin/criu-dev
 +
 
 +
You might need to read GIT documentation on how to prepare patches
 +
for mail submission. Take a look at http://book.git-scm.com/ and/or
 
http://git-scm.com/documentation for details. It should not be hard
 
http://git-scm.com/documentation for details. It should not be hard
 
at all.
 
at all.
  
2) Use "diff -up"
+
We recommend to post patches using <code>git send-email</code>
 +
   
 +
  git send-email --cover-letter --no-chain-reply-to --annotate \
 +
                --confirm=always --to=criu@openvz.org criu-dev
 +
 
 +
Note that the <code>git send-email</code> subcommand may not be in
 +
the main git package and using it may require installation of a
 +
separate package, for example the "git-email" package in Fedora and
 +
Debian.
 +
 
 +
If this is your first time using git send-email, you might need to
 +
configure it to point it to your SMTP server with something like:
  
Use <code>diff -up</code> or <code>diff -uprN</code> to create patches.
+
    git config --global sendemail.smtpServer stmp.example.net
  
=Signing your work=
+
If you get tired of typing <code>--to=criu@openvz.org</code> all the time,
 +
you can configure that to be automatically handled as well:
  
To improve tracking of who did what we've introduced a "sign-off" procedure
+
    git config sendemail.to criu@openvz.org
on patches that are being emailed around.
+
 
 +
If a developer is sending another version of the patch (e.g. to address
 +
review comments), they are advised to note differences to previous versions
 +
after the <code>---</code> line in the patch so that it helps reviewers but
 +
doesn't become part of git history. Moreover, such patch needs to be prefixed
 +
correctly with <code>--subject-prefix=PATCHv2</code> appended to
 +
<code>git send-email</code> (substitute <code>v2</code> with the correct
 +
version if needed though).
 +
 
 +
== Sign your work ==
 +
 
 +
To improve tracking of who did what, we ask you to sign off the patches
 +
that are to be emailed.
  
 
The sign-off is a simple line at the end of the explanation for the
 
The sign-off is a simple line at the end of the explanation for the
 
patch, which certifies that you wrote it or otherwise have the right to
 
patch, which certifies that you wrote it or otherwise have the right to
pass it on as a open-source patch.  The rules are pretty simple: if you
+
pass it on as an open-source patch.  The rules are pretty simple: if you
 
can certify the below:
 
can certify the below:
  
    Developer's Certificate of Origin 1.1
+
<div class="toccolours mw-collapsible mw-collapsed" style="width: 46em;">
   
+
'''Developer's Certificate of Origin 1.1'''
 +
<div class="mw-collapsible-content">
 
     By making a contribution to this project, I certify that:
 
     By making a contribution to this project, I certify that:
 
      
 
      
Line 69: Line 129:
 
         maintained indefinitely and may be redistributed consistent with
 
         maintained indefinitely and may be redistributed consistent with
 
         this project or the open source license(s) involved.
 
         this project or the open source license(s) involved.
 
+
</div></div>
 
then you just add a line saying
 
then you just add a line saying
  
Line 75: Line 135:
  
 
using your real name (please, no pseudonyms or anonymous contributions if
 
using your real name (please, no pseudonyms or anonymous contributions if
it possible)
+
it possible).
 +
 
 +
Hint: you can use <code>git commit -s</code> to add Signed-off-by line to your
 +
commit message. To append such line to a commit you already made, use
 +
<code>git commit --amend -s</code>.
  
=An example of patch message=
+
<div class="toccolours mw-collapsible mw-collapsed" style="width: 46em;">
 +
'''Example patch message'''
 +
<div class="mw-collapsible-content">
  
 
  From: Random J Developer <random at developer.example.org>
 
  From: Random J Developer <random at developer.example.org>
Line 88: Line 154:
 
  ---
 
  ---
 
  Patch body here
 
  Patch body here
 +
</div></div>
  
=Mailing patches=
+
== Mail patches ==
  
The patches should be sent to CRIU development mailing list
+
The patches should be sent to CRIU development mailing list, <code>criu AT openvz.org</code>. Note that you need to be subscribed first in order to post. The list web interface is available at https://openvz.org/mailman/listinfo/criu; you can also use standard mailman aliases to work with it.
which is located at https://openvz.org/mailman/listinfo/criu
 
  
Please make sure the email client you're using doesn't screw
+
Please make sure the email client you're using doesn't screw your patch (line wrapping and so on).
your patch (line wrapping and so on).
 
  
=Wait for response=
+
== Wait for response ==
  
 
Be patient. Most CRIU developers are pretty busy people so if
 
Be patient. Most CRIU developers are pretty busy people so if
there is no immediate response on your patch -- don't be surprised,
+
there is no immediate response on your patch don't be surprised,
sometimes a patch may fly around a week(s) before it get reviewed.
+
sometimes a patch may fly around a week before it gets reviewed.
But definitely the patches will not go to <code>/dev/null</code>.
+
 
 +
== Continuous integration ==
 +
 
 +
''Main article: [[Continuous integration]]''
 +
 
 +
CRIU tests are run for each series sent to the mailing list. If you get a message from our patchwork that patches failed to pass the tests, you have to investigate what is wrong.
 +
 
 +
We also recommend you to [[Continuous integration#Enable Travis CI for your repo|enable Travis CI for your repo]] to check patches in your git branch, before sending them to the mailing list.
 +
 
 +
[[Category:Development]]

Latest revision as of 18:31, 4 January 2019

Set up working environment[edit]

Although criu could be run as non-root (see Security), development is better to be done as root. For example, some tests require root. So, it would be a good idea to set up some recent Linux distro on a virtual machine.

Get the source code[edit]

The CRIU sources are tracked by Git. Official CRIU repo is at https://github.com/checkpoint-restore/criu.

The repository may contain multiple branches. Development happens in the criu-dev branch.

To clone CRIU repo and switch to the proper branch, run:

        git clone https://github.com/checkpoint-restore/criu criu
        cd criu
        git checkout criu-dev

Compile[edit]

First, you need to install compile-time dependencies. Check Installation#Dependencies for more info.

To compile CRIU, run:

       make

This should create the ./criu/criu executable.

Edit the source code[edit]

If you use ctags, you can generate the ctags file by running

       make tags

When you change the source code, please keep in mind the following code conventions:

Other conventions can be learned from the source code itself. In short, make sure your new code looks similar to what is already there.

Test your changes[edit]

CRIU comes with an extensive test suite. To check whether your changes introduce any regressions, run

        make test

The command runs ZDTM Test Suite. Check for any error messages produced by it.

In case you'd rather have someone else run the tests, you can use travis-ci for your own github fork of CRIU. It will check the compilation for various supported platforms, as well as run most of the tests from the suite. See https://travis-ci.org/checkpoint-restore/criu for more details.

Make a patch[edit]

To create a patch, run

   git format-patch --signoff origin/criu-dev

You might need to read GIT documentation on how to prepare patches for mail submission. Take a look at http://book.git-scm.com/ and/or http://git-scm.com/documentation for details. It should not be hard at all.

We recommend to post patches using git send-email

 git send-email --cover-letter --no-chain-reply-to --annotate \
                --confirm=always --to=criu@openvz.org criu-dev

Note that the git send-email subcommand may not be in the main git package and using it may require installation of a separate package, for example the "git-email" package in Fedora and Debian.

If this is your first time using git send-email, you might need to configure it to point it to your SMTP server with something like:

   git config --global sendemail.smtpServer stmp.example.net

If you get tired of typing --to=criu@openvz.org all the time, you can configure that to be automatically handled as well:

   git config sendemail.to criu@openvz.org

If a developer is sending another version of the patch (e.g. to address review comments), they are advised to note differences to previous versions after the --- line in the patch so that it helps reviewers but doesn't become part of git history. Moreover, such patch needs to be prefixed correctly with --subject-prefix=PATCHv2 appended to git send-email (substitute v2 with the correct version if needed though).

Sign your work[edit]

To improve tracking of who did what, we ask you to sign off the patches that are to be emailed.

The sign-off is a simple line at the end of the explanation for the patch, which certifies that you wrote it or otherwise have the right to pass it on as an open-source patch. The rules are pretty simple: if you can certify the below:

Developer's Certificate of Origin 1.1

   By making a contribution to this project, I certify that:
   
   (a) The contribution was created in whole or in part by me and I
       have the right to submit it under the open source license
       indicated in the file; or
   
   (b) The contribution is based upon previous work that, to the best
       of my knowledge, is covered under an appropriate open source
       license and I have the right under that license to submit that
       work with modifications, whether created in whole or in part
       by me, under the same open source license (unless I am
       permitted to submit under a different license), as indicated
       in the file; or
   
   (c) The contribution was provided directly to me by some other
       person who certified (a), (b) or (c) and I have not modified
       it.
   
   (d) I understand and agree that this project and the contribution
       are public and that a record of the contribution (including all
       personal information I submit with it, including my sign-off) is
       maintained indefinitely and may be redistributed consistent with
       this project or the open source license(s) involved.

then you just add a line saying

       Signed-off-by: Random J Developer <random at developer.example.org>

using your real name (please, no pseudonyms or anonymous contributions if it possible).

Hint: you can use git commit -s to add Signed-off-by line to your commit message. To append such line to a commit you already made, use git commit --amend -s.

Example patch message

From: Random J Developer <random at developer.example.org>
Subject: [PATCH] Short patch description

Long patch description (could be skipped if patch
is trivial enough)

Signed-off-by: Random J Developer <random at developer.example.org>
---
Patch body here

Mail patches[edit]

The patches should be sent to CRIU development mailing list, criu AT openvz.org. Note that you need to be subscribed first in order to post. The list web interface is available at https://openvz.org/mailman/listinfo/criu; you can also use standard mailman aliases to work with it.

Please make sure the email client you're using doesn't screw your patch (line wrapping and so on).

Wait for response[edit]

Be patient. Most CRIU developers are pretty busy people so if there is no immediate response on your patch — don't be surprised, sometimes a patch may fly around a week before it gets reviewed.

Continuous integration[edit]

Main article: Continuous integration

CRIU tests are run for each series sent to the mailing list. If you get a message from our patchwork that patches failed to pass the tests, you have to investigate what is wrong.

We also recommend you to enable Travis CI for your repo to check patches in your git branch, before sending them to the mailing list.