poky/documentation/dev-manual/quilt.rst
Michael Opdenacker 945c669138 manuals: split dev-manual/common-tasks.rst
A 500 KB source file is always harder to manage,
and can have section title conflicts.

So, the "Common Tasks" document is gone and all
its constituents are moved up one level.
You now have 40 chapters in the Development Tasks Manual.

(From yocto-docs rev: 8a45bc469411410020b8e688c137395fcaf3761b)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2022-12-01 19:20:29 +00:00

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3.6 KiB
ReStructuredText

.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
Using Quilt in Your Workflow
****************************
`Quilt <https://savannah.nongnu.org/projects/quilt>`__ is a powerful tool
that allows you to capture source code changes without having a clean
source tree. This section outlines the typical workflow you can use to
modify source code, test changes, and then preserve the changes in the
form of a patch all using Quilt.
.. note::
With regard to preserving changes to source files, if you clean a
recipe or have :ref:`rm_work <ref-classes-rm-work>` enabled, the
:ref:`devtool workflow <sdk-manual/extensible:using \`\`devtool\`\` in your sdk workflow>`
as described in the Yocto Project Application Development and the
Extensible Software Development Kit (eSDK) manual is a safer
development flow than the flow that uses Quilt.
Follow these general steps:
1. *Find the Source Code:* Temporary source code used by the
OpenEmbedded build system is kept in the :term:`Build Directory`. See the
":ref:`dev-manual/temporary-source-code:finding temporary source code`" section to
learn how to locate the directory that has the temporary source code for a
particular package.
2. *Change Your Working Directory:* You need to be in the directory that
has the temporary source code. That directory is defined by the
:term:`S` variable.
3. *Create a New Patch:* Before modifying source code, you need to
create a new patch. To create a new patch file, use ``quilt new`` as
below::
$ quilt new my_changes.patch
4. *Notify Quilt and Add Files:* After creating the patch, you need to
notify Quilt about the files you plan to edit. You notify Quilt by
adding the files to the patch you just created::
$ quilt add file1.c file2.c file3.c
5. *Edit the Files:* Make your changes in the source code to the files
you added to the patch.
6. *Test Your Changes:* Once you have modified the source code, the
easiest way to test your changes is by calling the :ref:`ref-tasks-compile`
task as shown in the following example::
$ bitbake -c compile -f package
The ``-f`` or ``--force`` option forces the specified task to
execute. If you find problems with your code, you can just keep
editing and re-testing iteratively until things work as expected.
.. note::
All the modifications you make to the temporary source code disappear
once you run the :ref:`ref-tasks-clean` or :ref:`ref-tasks-cleanall`
tasks using BitBake (i.e. ``bitbake -c clean package`` and
``bitbake -c cleanall package``). Modifications will also disappear if
you use the :ref:`rm_work <ref-classes-rm-work>` feature as described in
the ":ref:`dev-manual/disk-space:conserving disk space during builds`"
section.
7. *Generate the Patch:* Once your changes work as expected, you need to
use Quilt to generate the final patch that contains all your
modifications.
::
$ quilt refresh
At this point, the
``my_changes.patch`` file has all your edits made to the ``file1.c``,
``file2.c``, and ``file3.c`` files.
You can find the resulting patch file in the ``patches/``
subdirectory of the source (:term:`S`) directory.
8. *Copy the Patch File:* For simplicity, copy the patch file into a
directory named ``files``, which you can create in the same directory
that holds the recipe (``.bb``) file or the append (``.bbappend``)
file. Placing the patch here guarantees that the OpenEmbedded build
system will find the patch. Next, add the patch into the :term:`SRC_URI`
of the recipe. Here is an example::
SRC_URI += "file://my_changes.patch"