From patchwork Wed Aug 9 14:25:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Opdenacker X-Patchwork-Id: 28584 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BF24C41513 for ; Wed, 9 Aug 2023 14:25:37 +0000 (UTC) Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) by mx.groups.io with SMTP id smtpd.web11.89486.1691591129209565689 for ; Wed, 09 Aug 2023 07:25:29 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=pnYYEfme; spf=pass (domain: bootlin.com, ip: 217.70.183.200, mailfrom: michael.opdenacker@bootlin.com) Received: by mail.gandi.net (Postfix) with ESMTPSA id 1236C20007; Wed, 9 Aug 2023 14:25:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1691591127; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=KhkPO+DFzZduoMfiOzty7UyYdcszbcxsk4BZ7bFAAQ0=; b=pnYYEfmem3Sm/8RXIRv/017CY4Z0uoSa0M5gB6UwSpS6cFhB+pJKbGhDOvej6ni4GYTmXp +knIIkYurGmMkO8P9LsF/c5tO/lZza42u+svp8VQV/DDcz0l3wkLAPNmKNDM9D2hnBE7ha 9xNtwMNotaJ0uxOmXwIA9nWizaQ5Wo/BYf7XPdD7+UZZuvKx7+8djOrwXCW2AnOhEFCFxY 11HaLZrHL8C2cEkLelUafja1nJ5reHycLEEDSXyIKxn5dIbnCkQSMYGj75G8IwcLjJR9rY sq/+NYpR5cUteEKF6Th/18AvhlitKP/j+Wy5oOAJ0uLyEQsVtbNlbsy9PQhAmA== From: michael.opdenacker@bootlin.com To: docs@lists.yoctoproject.org Cc: Michael Opdenacker Subject: [PATCH 1/3] contributor-guide: add missing links to mailing lists Date: Wed, 9 Aug 2023 16:25:18 +0200 Message-Id: <20230809142520.226581-1-michael.opdenacker@bootlin.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-GND-Sasl: michael.opdenacker@bootlin.com List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 09 Aug 2023 14:25:37 -0000 X-Groupsio-URL: https://lists.yoctoproject.org/g/docs/message/4120 From: Michael Opdenacker And fix such a link too. Signed-off-by: Michael Opdenacker --- documentation/contributor-guide/submit-change.rst | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/documentation/contributor-guide/submit-change.rst b/documentation/contributor-guide/submit-change.rst index ba56e5986d..2555767102 100644 --- a/documentation/contributor-guide/submit-change.rst +++ b/documentation/contributor-guide/submit-change.rst @@ -52,7 +52,7 @@ varies by component: For changes to other layers hosted in the Yocto Project source repositories (i.e. ``yoctoproject.org``) and tools use the -:yocto_lists:`Yocto Project ` general mailing list. +:yocto_lists:`yocto ` general mailing list. .. note:: @@ -63,7 +63,8 @@ For additional recipes that do not fit into the core Metadata, you should determine which layer the recipe should go into and submit the change in the manner recommended by the documentation (e.g. the ``README`` file) supplied with the layer. If in doubt, please ask on the -Yocto general mailing list or on the openembedded-devel mailing list. +:yocto_lists:`yocto ` general mailing list or on the +:oe_lists:`openembedded-devel ` mailing list. You can also push a change upstream and request a maintainer to pull the change into the component's upstream repository. You do this by pushing From patchwork Wed Aug 9 14:25:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michael Opdenacker X-Patchwork-Id: 28582 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87A0BC04A6A for ; Wed, 9 Aug 2023 14:25:37 +0000 (UTC) Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by mx.groups.io with SMTP id smtpd.web10.89544.1691591131677996551 for ; Wed, 09 Aug 2023 07:25:32 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=ga8jS592; spf=pass (domain: bootlin.com, ip: 217.70.183.195, mailfrom: michael.opdenacker@bootlin.com) Received: by mail.gandi.net (Postfix) with ESMTPSA id E055B60009; Wed, 9 Aug 2023 14:25:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1691591129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OvG18oMg+53nk1OnQmTCWd3V5/UCXpTO063lCtAVGkM=; b=ga8jS592IiSRfiGFOor2TRQ9e7I+nDRVpsmdFF2g/iQWerqyj2nWbEeA4hsUtRI7H8fDE3 zW96pWNJpvGDa4cvpN9QSmj6Bings1P1JTCdxs/8RQfvY/TWeNYt/6wGSKTaBmEUePyje5 2KtQpAMDIvH3A4LQwIujHnZFqwkXYtHRkqmLqMrzz6Bjxn2Q3CmmegZG8yQ5qmT0V4CBOY 64D+3siGlET3FJ0S/m7OFbgN4fSKo9RNiD/sLAMmg2AZAztES59y+NYERfB2qcgoAaW1Ve fTTQMlu52wrgNUS+xKShjvMeDLV6kDFg71ZPkAhBQkTQ9pKBfdI8ntztWRs9Wg== From: michael.opdenacker@bootlin.com To: docs@lists.yoctoproject.org Cc: Michael Opdenacker , Richard Purdie Subject: [PATCH 2/3] contributor-guide: add section about why we use mailing lists Date: Wed, 9 Aug 2023 16:25:19 +0200 Message-Id: <20230809142520.226581-2-michael.opdenacker@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230809142520.226581-1-michael.opdenacker@bootlin.com> References: <20230809142520.226581-1-michael.opdenacker@bootlin.com> MIME-Version: 1.0 X-GND-Sasl: michael.opdenacker@bootlin.com List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 09 Aug 2023 14:25:37 -0000 X-Groupsio-URL: https://lists.yoctoproject.org/g/docs/message/4121 From: Michael Opdenacker Signed-off-by: Michael Opdenacker Signed-off-by: Richard Purdie --- .../contributor-guide/submit-change.rst | 41 ++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/documentation/contributor-guide/submit-change.rst b/documentation/contributor-guide/submit-change.rst index 2555767102..573491ecbc 100644 --- a/documentation/contributor-guide/submit-change.rst +++ b/documentation/contributor-guide/submit-change.rst @@ -8,10 +8,49 @@ Because the system is extremely configurable and flexible, we recognize that developers will want to extend, configure or optimize it for their specific uses. +.. _ref-why-mailing-lists: + +Contributing through mailing lists --- Why not using web-based workflows? +========================================================================= + +Both Yocto Project and OpenEmbedded have many key components that are +maintained by patches being submitted on mailing lists. We appreciate this +approach does look a little old fashioned when other workflows are available +through web technology such as GitHub, GitLab and others. Since we are often +asked this question, we’ve decided to document the reasons for using mailing +lists. + +One significant factor is that we value peer review. When a change is proposed +to many of the core pieces of the project, it helps to have many eyes of review +go over them. Whilst there is ultimately one maintainer who needs to make the +final call on accepting or rejecting a patch, the review is made by many eyes +and the exact people reviewing it are likely unknown to the maintainer. It is +often the surprise reviewer that catches the most interesting issues! + +This is in contrast to the "GitHub" style workflow where either just a +maintainer makes that review, or review is specifically requested from +nominated people. We believe there is significant value added to the codebase +by this peer review and that moving away from mailing lists would be to the +detriment of our code. + +We also need to acknowledge that many of our developers are used to this +mailing list workflow and have worked with it for years, with tools and +processes built around it. Changing away from this would result in a loss +of key people from the project, which would again be to its detriment. + +The projects are acutely aware that potential new contributors find the +mailing list approach off-putting and would prefer a point-and-click web GUI. +Since we don’t believe that can work for us, the project is aiming to ensure +`patchwork ` is available to help track +patch status and also looking at how tooling can provide more feedback to users +about patch status. We are looking at tools such as ``patchtest`` to +test user contributions before they hit the mailing lists and also at better +documenting how to use such workflows since we recognise that whilst this was +common knowledge a decade ago, it might not be as familiar now. + Finding a Suitable Mailing List =============================== -The Yocto Project uses a mailing list and a patch-based workflow that is similar to the Linux kernel but contains important differences. In general, there is a mailing list through which you can submit patches. You should send patches to the appropriate mailing list so that they can be From patchwork Wed Aug 9 14:25:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Michael Opdenacker X-Patchwork-Id: 28583 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7954DC0015E for ; Wed, 9 Aug 2023 14:25:37 +0000 (UTC) Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) by mx.groups.io with SMTP id smtpd.web11.89489.1691591132257860277 for ; Wed, 09 Aug 2023 07:25:32 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=KGio+S0d; spf=pass (domain: bootlin.com, ip: 217.70.183.200, mailfrom: michael.opdenacker@bootlin.com) Received: by mail.gandi.net (Postfix) with ESMTPSA id C5C5820007; Wed, 9 Aug 2023 14:25:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1691591130; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HcUeWOYXViH5dNSw60YNAuEQlvsa+6bSJU9sI6LlPXo=; b=KGio+S0dbLlFypG4oyf2M9HjluJYa7aieFZ6XUbohVYMK5+nE0rlonP3ys178uGzWShVtH 2A8DnFiN2bQScW5GmXUdeXnTOyQUYw+zpp5Va+RvwpIEBq3rjRjphGcV3Vvhc37kBFqXEZ LmCvTc6rVy6DLsOmWCF/jXhbgDj5kNuIrwSOo1iDUenblg9CMc7I/E+oP6YdSeGrTRgIOH +BqkhHggZDJLeOVOVkmflX0bMfzC44Htk3UE9M49y7wJbMAvpWyZ6TkadEC64LiDaWTLgx ac/5+TLBZk4PQbIx7PZ3yO4y6Xk3xQi4kOMDzJNqQgSkD3wtPJDWmDYg+v01AA== From: michael.opdenacker@bootlin.com To: docs@lists.yoctoproject.org Cc: Michael Opdenacker Subject: [PATCH 3/3] contributor-guide: add recipe style guide Date: Wed, 9 Aug 2023 16:25:20 +0200 Message-Id: <20230809142520.226581-3-michael.opdenacker@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230809142520.226581-1-michael.opdenacker@bootlin.com> References: <20230809142520.226581-1-michael.opdenacker@bootlin.com> MIME-Version: 1.0 X-GND-Sasl: michael.opdenacker@bootlin.com List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 09 Aug 2023 14:25:37 -0000 X-Groupsio-URL: https://lists.yoctoproject.org/g/docs/message/4122 From: Michael Opdenacker Signed-off-by: Michael Opdenacker --- documentation/contributor-guide/index.rst | 1 + .../contributor-guide/recipe-style-guide.rst | 263 ++++++++++++++++++ documentation/dev-manual/new-recipe.rst | 54 +--- 3 files changed, 268 insertions(+), 50 deletions(-) create mode 100644 documentation/contributor-guide/recipe-style-guide.rst diff --git a/documentation/contributor-guide/index.rst b/documentation/contributor-guide/index.rst index d723854843..7a39f994e2 100644 --- a/documentation/contributor-guide/index.rst +++ b/documentation/contributor-guide/index.rst @@ -20,6 +20,7 @@ this. identify-component submit-defect + recipe-style-guide submit-change .. include:: /boilerplate.rst diff --git a/documentation/contributor-guide/recipe-style-guide.rst b/documentation/contributor-guide/recipe-style-guide.rst new file mode 100644 index 0000000000..5210062802 --- /dev/null +++ b/documentation/contributor-guide/recipe-style-guide.rst @@ -0,0 +1,263 @@ +.. SPDX-License-Identifier: CC-BY-SA-2.0-UK + +Recipe Style Guide +****************** + +Recipe Naming Conventions +========================= + +In general, most recipes should follow the naming convention +``recipes-category/package/packagename_version.bb``. Recipes for related +projects may share the same package directory. ``packagename``, ``category``, +and ``package`` may contain hyphens, but hyphens are not allowed in ``version``. + +If the recipe is tracking a Git revision that does not correspond to a released +version of the software, ``version`` may be ``git`` (e.g. ``packagename_git.bb``) + +Version Policy +============== + +Our versions follow the form ``:-`` +or in BitBake variable terms ${:term:`PE`}:${:term:`PV`}-${:term:`PR`}. We +generally follow the `Debian `__ +version policy which defines these terms. + +In most cases the version :term:`PV` will be set automatically from the recipe +file name. It is recommended to use released versions of software as these are +revisions that upstream are expecting people to use. + +Package versions should always compare and sort correctly so that upgrades work +as expected. With conventional versions such as ``1.4`` upgrading ``to 1.5`` +this happens naturally, but some versions don't sort. For example, +``1.5 Release Candidate 2`` could be written as ``1.5rc2`` but this sorts after +``1.5``, so upgrades from feeds won't happen correctly. + +Instead the tilde (``~``) operator can be used, which sorts before the empty +string so ``1.5~rc2`` comes before ``1.5``. There is a historical syntax which +may be found where :term:`PV` is set as a combination of the prior version +``+`` the pre-release version, for example ``PV=1.4+1.5rc2``. This is a valid +syntax but the tilde form is preferred. + +For version comparisons, the ``opkg-compare-versions`` program from +``opkg-utils`` can be useful when attempting to determine how two version +numbers compare to each other. Our definitive version comparison algorithm is +the one within bitbake which aims to match those of the package managers and +Debian policy closely. + +When a recipe references a git revision that does not correspond to a released +version of software (e.g. is not a tagged version), the :term:`PV` variable +should include the Git revision using the following to make the +version clear:: + + PV = "+git${SRCPV}" + +In this case, ```` should be the most recently released version of the +software from the current source revision (``git describe`` can be useful for +determining this). Whilst not recommended for published layers, this format is +also useful when using :term:`AUTOREV` to set the recipe to increment source +control revisions automatically, which can be useful during local development. + +Version Number Changes +====================== + +The :term:`PR` variable is used to indicate different revisions of a recipe +that reference the same upstream source version. It can be used to force a +new version of a package to be installed onto a device from a package feed. +These once had to be set manually but in most cases these can now be set and +incremented automatically by a PR Server connected with a package feed. + +When :term:`PV` increases, any existing :term:`PR` value can and should be +removed. + +If :term:`PV` changes in such a way that it does not increase with respect to +the previous value, you need to increase :term:`PE` to ensure package managers +will upgrade it correctly. If unset you should set :term:`PE` to "1" since +the default of empty is easily confused with "0" depending on the package +manager. :term:`PE` can only have an integer value. + +Recipe formatting +================= + +Variable Formatting +------------------- + +- Variable assignment should a space around each side of the operator, e.g. + ``FOO = "bar"``, not ``FOO="bar"``. + +- Double quotes should be used on the right-hand side of the assignment, + e.g. ``FOO = "bar"`` not ``FOO = 'bar'`` + +- Spaces should be used for indenting variables, with 4 spaces per tab + +- Long variables should be split over multiple lines when possible by using + the continuation character (``\``) + +- When splitting a long variable over multiple lines, all continuation lines + should be indented (with spaces) to align with the start of the quote on the + first line:: + + FOO = "this line is \ + long \ + " + + Instead of:: + + FOO = "this line is \ + long \ + " + +Python Function formatting +-------------------------- + +- Spaces must be used for indenting Python code, with 4 spaces per tab + +Shell Function formatting +------------------------- + +- The formatting of shell functions should be consistent within layers. + Some use tabs, some use spaces. + +Recipe metadata +=============== + +Required Variables +------------------ + +The following variables should be included in all recipes: + +- :term:`SUMMARY`: a one line description of the upstream project + +- :term:`DESCRIPTION`: an extended description of the upstream project, + possibly with multiple lines. If no reasonable description can be written, + this may be omitted as it defaults to :term:`SUMMARY`. + +- :term:`HOMEPAGE`: the URL to the upstream projects homepage. + +- :term:`BUGTRACKER`: the URL upstream projects bug tracking website, + if applicable. + +Recipe Ordering +--------------- + +When a variable is defined in recipes and classes, variables should follow the +general order when possible: + +- :term:`SUMMARY` +- :term:`DESCRIPTION` +- :term:`AUTHOR` +- :term:`HOMEPAGE` +- :term:`BUGTRACKER` +- :term:`SECTION` +- :term:`LICENSE` +- :term:`LIC_FILES_CHKSUM` +- :term:`DEPENDS` +- :term:`PROVIDES` +- :term:`PV` +- :term:`SRC_URI` +- :term:`SRCREV` +- :term:`S` +- ``inherit ...`` +- :term:`PACKAGECONFIG` +- Build class specific variables such as ``EXTRA_QMAKEVARS_POST`` and :term:`EXTRA_OECONF` +- Tasks such as :ref:`ref-tasks-configure` +- :term:`PACKAGE_ARCH` +- :term:`PACKAGES` +- :term:`FILES` +- :term:`RDEPENDS` +- :term:`RRECOMMENDS` +- :term:`RSUGGESTS` +- :term:`RPROVIDES` +- :term:`RCONFLICTS` +- :term:`BBCLASSEXTEND` + +There are some cases where ordering is important and these cases would override +this default order. Examples include: + +- :term:`PACKAGE_ARCH` needing to be set before ``inherit packagegroup`` + +Tasks should be ordered based on the order they generally execute. For commonly +used tasks this would be: + +- :ref:`ref-tasks-fetch` +- :ref:`ref-tasks-unpack` +- :ref:`ref-tasks-patch` +- :ref:`ref-tasks-prepare_recipe_sysroot` +- :ref:`ref-tasks-configure` +- :ref:`ref-tasks-compile` +- :ref:`ref-tasks-install` +- :ref:`ref-tasks-populate_sysroot` +- :ref:`ref-tasks-package` + +Custom tasks should be sorted similarly. + +Package specific variables are typically grouped together, e.g.:: + + RDEPENDS:${PN} = “foo” + RDEPENDS:${PN}-libs = “bar” + + RRECOMMENDS:${PN} = “one” + RRECOMMENDS:${PN}-libs = “two” + +Recipe License Fields +--------------------- + +Recipes need to define both the :term:`LICENSE` and +:term:`LIC_FILES_CHKSUM` variables: + +- :term:`LICENSE`: This variable specifies the license for the software. + If you do not know the license under which the software you are + building is distributed, you should go to the source code and look + for that information. Typical files containing this information + include ``COPYING``, :term:`LICENSE`, and ``README`` files. You could + also find the information near the top of a source file. For example, + given a piece of software licensed under the GNU General Public + License version 2, you would set :term:`LICENSE` as follows:: + + LICENSE = "GPL-2.0-only" + + The licenses you specify within :term:`LICENSE` can have any name as long + as you do not use spaces, since spaces are used as separators between + license names. For standard licenses, use the names of the files in + ``meta/files/common-licenses/`` or the :term:`SPDXLICENSEMAP` flag names + defined in ``meta/conf/licenses.conf``. + +- :term:`LIC_FILES_CHKSUM`: The OpenEmbedded build system uses this + variable to make sure the license text has not changed. If it has, + the build produces an error and it affords you the chance to figure + it out and correct the problem. + + You need to specify all applicable licensing files for the software. + At the end of the configuration step, the build process will compare + the checksums of the files to be sure the text has not changed. Any + differences result in an error with the message containing the + current checksum. For more explanation and examples of how to set the + :term:`LIC_FILES_CHKSUM` variable, see the + ":ref:`dev-manual/licenses:tracking license changes`" section. + + To determine the correct checksum string, you can list the + appropriate files in the :term:`LIC_FILES_CHKSUM` variable with incorrect + md5 strings, attempt to build the software, and then note the + resulting error messages that will report the correct md5 strings. + See the ":ref:`dev-manual/new-recipe:fetching code`" section for + additional information. + + Here is an example that assumes the software has a ``COPYING`` file:: + + LIC_FILES_CHKSUM = "file://COPYING;md5=xxx" + + When you try to build the + software, the build system will produce an error and give you the + correct string that you can substitute into the recipe file for a + subsequent build. + +Tips and Guidelines for Writing Recipes +--------------------------------------- + +- Use :term:`BBCLASSEXTEND` instead of creating separate recipes such as ``-native`` + and ``-nativesdk`` ones, whenever possible. This avoids having to maintain multiple + recipe files at the same time. + +- Avoid manually mangling ``pkg-config`` ``.pc`` files. + Recipes using ``pkg-config`` should use variables to ensure they are correctly + relocatable and not need manual path correction in the recipe. + diff --git a/documentation/dev-manual/new-recipe.rst b/documentation/dev-manual/new-recipe.rst index af390773a9..cb9533ff5d 100644 --- a/documentation/dev-manual/new-recipe.rst +++ b/documentation/dev-manual/new-recipe.rst @@ -432,56 +432,10 @@ named the same as the base name of the recipe Licensing ========= -Your recipe needs to have both the -:term:`LICENSE` and -:term:`LIC_FILES_CHKSUM` -variables: - -- :term:`LICENSE`: This variable specifies the license for the software. - If you do not know the license under which the software you are - building is distributed, you should go to the source code and look - for that information. Typical files containing this information - include ``COPYING``, :term:`LICENSE`, and ``README`` files. You could - also find the information near the top of a source file. For example, - given a piece of software licensed under the GNU General Public - License version 2, you would set :term:`LICENSE` as follows:: - - LICENSE = "GPL-2.0-only" - - The licenses you specify within :term:`LICENSE` can have any name as long - as you do not use spaces, since spaces are used as separators between - license names. For standard licenses, use the names of the files in - ``meta/files/common-licenses/`` or the :term:`SPDXLICENSEMAP` flag names - defined in ``meta/conf/licenses.conf``. - -- :term:`LIC_FILES_CHKSUM`: The OpenEmbedded build system uses this - variable to make sure the license text has not changed. If it has, - the build produces an error and it affords you the chance to figure - it out and correct the problem. - - You need to specify all applicable licensing files for the software. - At the end of the configuration step, the build process will compare - the checksums of the files to be sure the text has not changed. Any - differences result in an error with the message containing the - current checksum. For more explanation and examples of how to set the - :term:`LIC_FILES_CHKSUM` variable, see the - ":ref:`dev-manual/licenses:tracking license changes`" section. - - To determine the correct checksum string, you can list the - appropriate files in the :term:`LIC_FILES_CHKSUM` variable with incorrect - md5 strings, attempt to build the software, and then note the - resulting error messages that will report the correct md5 strings. - See the ":ref:`dev-manual/new-recipe:fetching code`" section for - additional information. - - Here is an example that assumes the software has a ``COPYING`` file:: - - LIC_FILES_CHKSUM = "file://COPYING;md5=xxx" - - When you try to build the - software, the build system will produce an error and give you the - correct string that you can substitute into the recipe file for a - subsequent build. +Your recipe needs to define variables related to the license +under whith the software is distributed. See the +:ref:`contributor-guide/recipe-style-guide:recipe license fields` +section in the Contributor Guide for details. Dependencies ============