Styleguide

Naming Conventions

Use $packagename_$version.bb

Format Guidelines

• No spaces are allowed behind the line continuation symbol
• The correct spacing for a variable is FOO = "BAR".
• Use quotes on the right hand side of assignments: FOO = "BAR"
• Comments inside bb files are allowed using the '#' character at the beginning of a line.
• Use spaces for indentation as developers tends to use different amount of spaces per one tab.
• Indentation of multiline variables such as SRC_URI is desireable.
• Python functions should be four space indented, no tabs.
• Shell functions are usually tab character indented.

Style Checking tools

Please run ./contrib/oe-stylize.py on your recipes before submitting them.

Style Guidelines

• Put the inherit declaration after the initial variables are set up and before any custom do_ routines. This is flexible as ordering is often important.
• If you define custom do_ routines, keep them in the order of the tasks being executed, that is:
  • do_fetch
  • do_unpack
  • do_patch
  • do_configure
  • do_compile
  • do_install
  • do_populate_sysroot
  • do_package

• Don't use cp to put files into staging or destination directories, use install instead.
• Don't use mkdir to create destination directories, use install -d instead.

• There is a standard set of variables often found in a .bb file and the preferred order (to make the file easily readable to seasoned developers) is
  • DESCRIPTION
  • AUTHOR
  • HOMEPAGE
  • SECTION
  • PRIORITY
  • LICENSE
  • DEPENDS
  • RDEPENDS
  • RRECOMMENDS
  • RSUGGESTS
  • PROVIDES
  • RPROVIDES
  • RCONFLICTS
  • SRCDATE
  • PV
  • PR
  • SRC_URI
  • S
  • inherit ...
  • build class specific variables, i.e. EXTRA_QMAKEVARS_POST
  • task overrides, i.e. do_configure
  • PACKAGE_ARCH
  • PACKAGES
  • FILES

• Package related variables for a given package are often grouped together for clarity.

Example Recipe

SUMMARY = "X11 Code Viewer"
DESCRIPTION = "Allow viewing of X11 code in a fancy way which allows easier \
               and more productive X11 programming"
AUTHOR = "John Bazz <john.bazz@example.org>"
HOMEPAGE = "http://www.example.org/xcv/"
SECTION = "x11/applications"
LICENSE = "GPL-2.0"
DEPENDS = "libsm libx11 libxext libxaw"
PV = "0.9+git${SRCPV}"

# upstream does not yet publish any release so we have to fetch last working version from GIT
SRCREV = "6a5e79ae8a0f4a273a603b2df1742972510d3d8f"
SRC_URI = "git://xcv.example.org/xcv;protocol=http \
           file://toolbar-resize-fix.patch"

S = "${WORKDIR}/xcv/"

inherit autotools

do_configure_prepend() {
    rm ${S}/aclocal.m4
}

do_install() {
    install -d ${D}${bindir}
    install -d ${D}${mandir}/man1

    install -m 0755 xcv ${D}${bindir}/   
    install -m 0644 xcv.1.gz ${D}${mandir}/man1/
}

RDEPENDS_${PN} = "shared-mime-info"
RRECOMMENDS_${PN} = "ctags"
RCONFLICTS_${PN} = "xcv2"

PR variables with recipes that use INC files

When recipe include files are used, the PR handling gets kind of messy. Its a pain to have to audit the PR in all the dependent recipes when you change something in an INC file. We usually use the following solution:

recipe: PR = "${INC_PR}.1"

inc file: INC_PR = "r1"

When converting existing recipes to use INC_PR, set the initial INC_PR to the maximum of the current PRs.

Also see https://wiki.yoctoproject.org/wiki/Recipe_%26_Patch_Style_Guide