[PATCH v3 2/4] meta: Support opting out of any distro features

[Paul Barker <paul@pbarker.dev>]

Add default values to DISTRO_FEATURES using the new
filter_default_features() function.

This change obsoletes the variables DISTRO_FEATURES_BACKFILL and
DISTRO_FEATURES_BACKFILL_CONSIDERED. Instead, all defaults are added via
DISTRO_FEATURES_DEFAULTS and users can opt out of any of these using
DISTRO_FEATURES_OPTED_OUT. Hopefully the variable naming here is easier
for people to understand and remember.

Migration notes:

- If you have previously assigned DISTRO_FEATURES without using
  DISTRO_FEATURES_DEFAULT, you will now get the default features added
  automatically. You will need to review these and add any features you
  do not want to use to DISTRO_FEATURES_OPTED_OUT.

- DISTRO_FEATURES_DEFAULT is now unused, the new variable name is
  slighlty different to ensure that it is not accidentally used if a
  layer hasn't been modified to adapt to the new naming.

- If you previously set DISTRO_FEATURES_BACKFILL_CONSIDERED, use the new
  variable DISTRO_FEATURES_OPTED_OUT instead.

- If you previously modified DISTRO_FEATURES_BACKFILL, don't do that.

Signed-off-by: Paul Barker <paul@pbarker.dev>
---
 meta/classes-global/base.bbclass                |  5 ++++-
 meta/classes-recipe/crosssdk.bbclass            |  8 ++++----
 meta/classes-recipe/native.bbclass              |  8 ++++----
 meta/classes-recipe/nativesdk.bbclass           |  8 ++++----
 meta/conf/bitbake.conf                          |  1 -
 meta/conf/distro/include/default-distrovars.inc | 15 +++++++++------
 meta/conf/distro/include/tclibc-musl.inc        |  2 +-
 meta/conf/distro/include/tclibc-newlib.inc      |  2 +-
 meta/conf/distro/include/tclibc-picolibc.inc    |  2 +-
 meta/conf/documentation.conf                    |  4 ++--
 10 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/meta/classes-global/base.bbclass b/meta/classes-global/base.bbclass
index 22b427a5211b..0a4cfd594c72 100644
--- a/meta/classes-global/base.bbclass
+++ b/meta/classes-global/base.bbclass
@@ -454,8 +454,11 @@ def set_packagetriplet(d):
 python () {
     import string, re
 
+    # Filter default features to allow users to opt out of features they don't
+    # want.
+    oe.utils.filter_default_features("DISTRO_FEATURES", d)
+
     # Handle backfilling
-    oe.utils.features_backfill("DISTRO_FEATURES", d)
     oe.utils.features_backfill("MACHINE_FEATURES", d)
 
     # To add a recipe to the skip list , set:
diff --git a/meta/classes-recipe/crosssdk.bbclass b/meta/classes-recipe/crosssdk.bbclass
index a2853e6a9201..dac18b39edb2 100644
--- a/meta/classes-recipe/crosssdk.bbclass
+++ b/meta/classes-recipe/crosssdk.bbclass
@@ -16,13 +16,13 @@ PACKAGE_ARCH = "${SDK_ARCH}"
 python () {
     # set TUNE_PKGARCH to SDK_ARCH
     d.setVar('TUNE_PKGARCH', d.getVar('SDK_ARCH'))
-    # Set features here to prevent appends and distro features backfill
-    # from modifying nativesdk distro features
+    # Set features here to prevent DISTRO_FEATURES modifications from affecting
+    # crosssdk distro features
     features = set(d.getVar("DISTRO_FEATURES_NATIVESDK").split())
-    oe.utils.features_backfill("DISTRO_FEATURES", d)
+    oe.utils.filter_default_features("DISTRO_FEATURES", d)
     filtered = set(bb.utils.filter("DISTRO_FEATURES", d.getVar("DISTRO_FEATURES_FILTER_NATIVESDK"), d).split())
     d.setVar("DISTRO_FEATURES", " ".join(sorted(features | filtered)))
-    d.setVar("DISTRO_FEATURES_BACKFILL", "")
+    d.setVar("DISTRO_FEATURES_DEFAULTS", "")
 }
 
 STAGING_BINDIR_TOOLCHAIN = "${STAGING_DIR_NATIVE}${bindir_native}/${TARGET_ARCH}${TARGET_VENDOR}-${TARGET_OS}"
diff --git a/meta/classes-recipe/native.bbclass b/meta/classes-recipe/native.bbclass
index 5aa9c8e4145e..9f4ca170f762 100644
--- a/meta/classes-recipe/native.bbclass
+++ b/meta/classes-recipe/native.bbclass
@@ -126,13 +126,13 @@ python native_virtclass_handler () {
         return
     bpn = d.getVar("BPN")
 
-    # Set features here to prevent appends and distro features backfill
-    # from modifying native distro features
+    # Set features here to prevent DISTRO_FEATURES modifications from affecting
+    # native distro features
     features = set(d.getVar("DISTRO_FEATURES_NATIVE").split())
-    oe.utils.features_backfill("DISTRO_FEATURES", d)
+    oe.utils.filter_default_features("DISTRO_FEATURES", d)
     filtered = set(bb.utils.filter("DISTRO_FEATURES", d.getVar("DISTRO_FEATURES_FILTER_NATIVE"), d).split())
     d.setVar("DISTRO_FEATURES", " ".join(sorted(features | filtered)))
-    d.setVar("DISTRO_FEATURES_BACKFILL", "")
+    d.setVar("DISTRO_FEATURES_DEFAULTS", "")
 
     classextend = d.getVar('BBCLASSEXTEND') or ""
     if "native" not in classextend:
diff --git a/meta/classes-recipe/nativesdk.bbclass b/meta/classes-recipe/nativesdk.bbclass
index 5adb7515bf14..a4801c48b2de 100644
--- a/meta/classes-recipe/nativesdk.bbclass
+++ b/meta/classes-recipe/nativesdk.bbclass
@@ -78,13 +78,13 @@ python nativesdk_virtclass_handler () {
     if not (pn.endswith("-nativesdk") or pn.startswith("nativesdk-")):
         return
 
-    # Set features here to prevent appends and distro features backfill
-    # from modifying nativesdk distro features
+    # Set features here to prevent DISTRO_FEATURES modifications from affecting
+    # nativesdk distro features
     features = set(d.getVar("DISTRO_FEATURES_NATIVESDK").split())
-    oe.utils.features_backfill("DISTRO_FEATURES", d)
+    oe.utils.filter_default_features("DISTRO_FEATURES", d)
     filtered = set(bb.utils.filter("DISTRO_FEATURES", d.getVar("DISTRO_FEATURES_FILTER_NATIVESDK"), d).split())
     d.setVar("DISTRO_FEATURES", " ".join(sorted(features | filtered)))
-    d.setVar("DISTRO_FEATURES_BACKFILL", "")
+    d.setVar("DISTRO_FEATURES_DEFAULTS", "")
 
     e.data.setVar("MLPREFIX", "nativesdk-")
     e.data.setVar("PN", "nativesdk-" + e.data.getVar("PN").replace("-nativesdk", "").replace("nativesdk-", ""))
diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 6b3443695a04..f851e2adc9f7 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -912,7 +912,6 @@ DISTRO_FEATURES_NATIVESDK:mingw32 = "x11 ipv6"
 DISTRO_FEATURES_FILTER_NATIVE ?= "api-documentation debuginfod opencl opengl wayland"
 DISTRO_FEATURES_FILTER_NATIVESDK ?= "api-documentation debuginfod opencl opengl wayland"
 
-DISTRO_FEATURES_BACKFILL = "pulseaudio gobject-introspection-data ldconfig opengl ptest multiarch wayland vulkan"
 MACHINE_FEATURES_BACKFILL = "rtc qemu-usermode"
 
 COMBINED_FEATURES = "${@oe.utils.set_intersect('DISTRO_FEATURES', 'MACHINE_FEATURES', d)}"
diff --git a/meta/conf/distro/include/default-distrovars.inc b/meta/conf/distro/include/default-distrovars.inc
index 7adcdfad4ff4..daa4d2a74dda 100644
--- a/meta/conf/distro/include/default-distrovars.inc
+++ b/meta/conf/distro/include/default-distrovars.inc
@@ -14,19 +14,22 @@ LOCALE_UTF8_IS_DEFAULT ?= "1"
 LOCALE_UTF8_IS_DEFAULT:class-nativesdk = "0"
 
 # seccomp is not yet ported to rv32
-DISTRO_FEATURES_DEFAULT:remove:riscv32 = "seccomp"
+DISTRO_FEATURES_OPTED_OUT:append:riscv32 = "seccomp"
 
 # seccomp is not yet ported to ARC
-DISTRO_FEATURES_DEFAULT:remove:arc = "seccomp"
+DISTRO_FEATURES_OPTED_OUT:append:arc = "seccomp"
 
 # seccomp is not yet ported to microblaze
-DISTRO_FEATURES_DEFAULT:remove:microblaze = "seccomp"
+DISTRO_FEATURES_OPTED_OUT:append:microblaze = "seccomp"
 
 # seccomp is not yet ported to loongarch64
-DISTRO_FEATURES_DEFAULT:remove:loongarch64 = "seccomp"
+DISTRO_FEATURES_OPTED_OUT:append:loongarch64 = "seccomp"
 
-DISTRO_FEATURES_DEFAULT ?= "acl alsa bluetooth debuginfod ext2 ipv4 ipv6 pcmcia usbgadget usbhost wifi xattr nfs zeroconf pci 3g nfc x11 vfat seccomp"
-DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT}"
+DISTRO_FEATURES_DEFAULTS ?= " \
+    acl alsa bluetooth debuginfod ext2 ipv4 ipv6 pcmcia usbgadget usbhost \
+    wifi xattr nfs zeroconf pci 3g nfc x11 vfat seccomp pulseaudio \
+    gobject-introspection-data ldconfig opengl ptest multiarch wayland vulkan \
+    "
 IMAGE_FEATURES ?= ""
 
 COMMERCIAL_AUDIO_PLUGINS ?= ""
diff --git a/meta/conf/distro/include/tclibc-musl.inc b/meta/conf/distro/include/tclibc-musl.inc
index 98d7a801ac84..a61a6ced0dd2 100644
--- a/meta/conf/distro/include/tclibc-musl.inc
+++ b/meta/conf/distro/include/tclibc-musl.inc
@@ -14,7 +14,7 @@ PREFERRED_PROVIDER_virtual/libc-locale ?= "musl-locales"
 PREFERRED_PROVIDER_virtual/nativesdk-libintl ?= "nativesdk-glibc"
 PREFERRED_PROVIDER_virtual/nativesdk-libiconv ?= "nativesdk-glibc"
 
-DISTRO_FEATURES_BACKFILL_CONSIDERED += "ldconfig"
+DISTRO_FEATURES_OPTED_OUT += "ldconfig"
 
 #USE_NLS ?= "no"
 
diff --git a/meta/conf/distro/include/tclibc-newlib.inc b/meta/conf/distro/include/tclibc-newlib.inc
index 34318b24549c..fff9b9f066fb 100644
--- a/meta/conf/distro/include/tclibc-newlib.inc
+++ b/meta/conf/distro/include/tclibc-newlib.inc
@@ -11,7 +11,7 @@ PREFERRED_PROVIDER_virtual/libintl ?= "newlib"
 PREFERRED_PROVIDER_virtual/nativesdk-libintl ?= "nativesdk-glibc"
 PREFERRED_PROVIDER_virtual/nativesdk-libiconv ?= "nativesdk-glibc"
 
-DISTRO_FEATURES_BACKFILL_CONSIDERED += "ldconfig"
+DISTRO_FEATURES_OPTED_OUT += "ldconfig"
 
 #USE_NLS ?= "no"
 
diff --git a/meta/conf/distro/include/tclibc-picolibc.inc b/meta/conf/distro/include/tclibc-picolibc.inc
index 2cd26cfd7dcd..6134b0d97d6a 100644
--- a/meta/conf/distro/include/tclibc-picolibc.inc
+++ b/meta/conf/distro/include/tclibc-picolibc.inc
@@ -11,7 +11,7 @@ PREFERRED_PROVIDER_virtual/libintl ?= "picolibc"
 PREFERRED_PROVIDER_virtual/nativesdk-libintl ?= "nativesdk-glibc"
 PREFERRED_PROVIDER_virtual/nativesdk-libiconv ?= "nativesdk-glibc"
 
-DISTRO_FEATURES_BACKFILL_CONSIDERED += "ldconfig"
+DISTRO_FEATURES_OPTED_OUT += "ldconfig"
 
 IMAGE_LINGUAS = ""
 
diff --git a/meta/conf/documentation.conf b/meta/conf/documentation.conf
index 1853676fa060..5c93d0e47970 100644
--- a/meta/conf/documentation.conf
+++ b/meta/conf/documentation.conf
@@ -141,8 +141,8 @@ DISTRO[doc] = "The short name of the distribution. If the variable is blank, met
 DISTRO_EXTRA_RDEPENDS[doc] = "Specifies a list of distro-specific packages to add to all images. The variable only applies to the images that include packagegroup-base."
 DISTRO_EXTRA_RRECOMMENDS[doc] = "Specifies a list of distro-specific packages to add to all images if the packages exist. The list of packages are automatically installed but you can remove them."
 DISTRO_FEATURES[doc] = "The features enabled for the distribution."
-DISTRO_FEATURES_BACKFILL[doc] = "Features to be added to DISTRO_FEATURES if not also present in DISTRO_FEATURES_BACKFILL_CONSIDERED. This variable is set in the meta/conf/bitbake.conf file and it is not intended to be user-configurable."
-DISTRO_FEATURES_BACKFILL_CONSIDERED[doc] = "Features from DISTRO_FEATURES_BACKFILL that should not be backfilled (i.e. added to DISTRO_FEATURES) during the build."
+DISTRO_FEATURES_DEFAULTS[doc] = "The default set of distribution features, prior to any filtering. Usually you should leave this alone and modify DISTRO_FEATURES and/or DISTRO_FEATURES_OPTED_OUT."
+DISTRO_FEATURES_OPTED_OUT[doc] = "The set of default distribtion features to disable. Prefer opting out of features using this variable instead of using DISTRO_FEATURES:remove."
 DISTRO_NAME[doc] = "The long name of the distribution."
 DISTRO_PN_ALIAS[doc] = "Alias names used for the recipe in various Linux distributions."
 DISTRO_VERSION[doc] = "The version of the distribution."

-- 
2.43.0