1.. SPDX-License-Identifier: CC-BY-SA-2.0-UK 2 3Using Quilt in Your Workflow 4**************************** 5 6`Quilt <https://savannah.nongnu.org/projects/quilt>`__ is a powerful tool 7that allows you to capture source code changes without having a clean 8source tree. This section outlines the typical workflow you can use to 9modify source code, test changes, and then preserve the changes in the 10form of a patch all using Quilt. 11 12.. note:: 13 14 With regard to preserving changes to source files, if you clean a 15 recipe or have :ref:`ref-classes-rm-work` enabled, the 16 :ref:`devtool workflow <sdk-manual/extensible:using \`\`devtool\`\` in your sdk workflow>` 17 as described in the Yocto Project Application Development and the 18 Extensible Software Development Kit (eSDK) manual is a safer 19 development flow than the flow that uses Quilt. 20 21Follow these general steps: 22 23#. *Find the Source Code:* Temporary source code used by the 24 OpenEmbedded build system is kept in the :term:`Build Directory`. See the 25 ":ref:`dev-manual/temporary-source-code:finding temporary source code`" section to 26 learn how to locate the directory that has the temporary source code for a 27 particular package. 28 29#. *Change Your Working Directory:* You need to be in the directory that 30 has the temporary source code. That directory is defined by the 31 :term:`S` variable. 32 33#. *Create a New Patch:* Before modifying source code, you need to 34 create a new patch. To create a new patch file, use ``quilt new`` as 35 below:: 36 37 $ quilt new my_changes.patch 38 39#. *Notify Quilt and Add Files:* After creating the patch, you need to 40 notify Quilt about the files you plan to edit. You notify Quilt by 41 adding the files to the patch you just created:: 42 43 $ quilt add file1.c file2.c file3.c 44 45#. *Edit the Files:* Make your changes in the source code to the files 46 you added to the patch. 47 48#. *Test Your Changes:* Once you have modified the source code, the 49 easiest way to test your changes is by calling the :ref:`ref-tasks-compile` 50 task as shown in the following example:: 51 52 $ bitbake -c compile -f package 53 54 The ``-f`` or ``--force`` option forces the specified task to 55 execute. If you find problems with your code, you can just keep 56 editing and re-testing iteratively until things work as expected. 57 58 .. note:: 59 60 All the modifications you make to the temporary source code disappear 61 once you run the :ref:`ref-tasks-clean` or :ref:`ref-tasks-cleanall` 62 tasks using BitBake (i.e. ``bitbake -c clean package`` and 63 ``bitbake -c cleanall package``). Modifications will also disappear if 64 you use the :ref:`ref-classes-rm-work` feature as described in 65 the ":ref:`dev-manual/disk-space:conserving disk space during builds`" 66 section. 67 68#. *Generate the Patch:* Once your changes work as expected, you need to 69 use Quilt to generate the final patch that contains all your 70 modifications:: 71 72 $ quilt refresh 73 74 At this point, the 75 ``my_changes.patch`` file has all your edits made to the ``file1.c``, 76 ``file2.c``, and ``file3.c`` files. 77 78 You can find the resulting patch file in the ``patches/`` 79 subdirectory of the source (:term:`S`) directory. 80 81#. *Copy the Patch File:* For simplicity, copy the patch file into a 82 directory named ``files``, which you can create in the same directory 83 that holds the recipe (``.bb``) file or the append (``.bbappend``) 84 file. Placing the patch here guarantees that the OpenEmbedded build 85 system will find the patch. Next, add the patch into the :term:`SRC_URI` 86 of the recipe. Here is an example:: 87 88 SRC_URI += "file://my_changes.patch" 89 90