[PATCH v3 1/4] oelib: utils: Support filtering default features

[Paul Barker <paul@pbarker.dev>]

The new library function filter_default_features() allows us to support
opting out of any default features without having to use :remove.

Signed-off-by: Paul Barker <paul@pbarker.dev>
---
 meta/lib/oe/utils.py                        | 34 ++++++++++++++++++++++++++
 meta/lib/oeqa/selftest/cases/oelib/utils.py | 38 ++++++++++++++++++++++++++++-
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
index afcfeda0c6d5..52f2f1bd55e0 100644
--- a/meta/lib/oe/utils.py
+++ b/meta/lib/oe/utils.py
@@ -83,6 +83,31 @@ def set_intersect(variable1, variable2, d):
     val2 = set(d.getVar(variable2).split())
     return " ".join(val1 & val2)
 
+def set_difference(variable1, variable2, d):
+    """
+    Expand both variables, interpret them as lists of strings, and return the
+    intersection as a flattened string.
+
+    For example:
+    s1 = "a b c"
+    s2 = "b c d"
+    s3 = set_difference(s1, s2)
+    => s3 = "a"
+    """
+    val1 = d.getVar(variable1)
+    if not val1:
+        return ""
+    val2 = d.getVar(variable2)
+    if not val2:
+        return val1
+
+    val1 = set(val1.split())
+    val2 = set(val2.split())
+
+    # Return a sorted string to ensure that the result is consistent between
+    # parser runs.
+    return " ".join(sorted(val1 - val2))
+
 def prune_suffix(var, suffixes, d):
     # See if var ends with any of the suffixes listed and
     # remove it if found
@@ -133,6 +158,15 @@ def features_backfill(var,d):
     if addfeatures:
         d.appendVar(var, " " + " ".join(addfeatures))
 
+def filter_default_features(varname, d):
+    # Process default features to exclude features which the user has opted out
+    # of. The result is appended to the target variable (e.g. DISTRO_FEATURES
+    # or MACHINE_FEATURES).
+    default_features = set_difference(varname + "_DEFAULTS",
+                                      varname + "_OPTED_OUT",
+                                      d)
+    d.appendVar(varname, " " + default_features)
+
 def all_distro_features(d, features, truevalue="1", falsevalue=""):
     """
     Returns truevalue if *all* given features are set in DISTRO_FEATURES,
diff --git a/meta/lib/oeqa/selftest/cases/oelib/utils.py b/meta/lib/oeqa/selftest/cases/oelib/utils.py
index 0cb46425a02d..a72a0f5983f1 100644
--- a/meta/lib/oeqa/selftest/cases/oelib/utils.py
+++ b/meta/lib/oeqa/selftest/cases/oelib/utils.py
@@ -8,7 +8,7 @@ import sys
 from unittest.case import TestCase
 from contextlib import contextmanager
 from io import StringIO
-from oe.utils import packages_filter_out_system, trim_version, multiprocess_launch
+from oe.utils import packages_filter_out_system, trim_version, multiprocess_launch, filter_default_features
 
 class TestPackagesFilterOutSystem(TestCase):
     def test_filter(self):
@@ -102,3 +102,39 @@ class TestMultiprocessLaunch(TestCase):
         with captured_output() as (out, err):
             self.assertRaises(bb.BBHandledException, multiprocess_launch, testfunction, ["1", "2", "3", "4", "5", "6"], d, extraargs=(d,))
         self.assertIn("KeyError: 'Invalid number 2'", out.getvalue())
+
+
+class TestDefaultFeatures(TestCase):
+    def test_filter_default_features(self):
+        try:
+            import bb
+            d = bb.data_smart.DataSmart()
+        except ImportError:
+            self.skipTest("Cannot import bb")
+
+        # Test with nothing opted out
+        d.setVar("DISTRO_FEATURES", "")
+        d.setVar("DISTRO_FEATURES_DEFAULTS", "alpha beta gamma")
+        filter_default_features("DISTRO_FEATURES", d)
+        self.assertEqual(d.getVar("DISTRO_FEATURES").strip(), "alpha beta gamma")
+
+        # opt out of a single feature
+        d.setVar("DISTRO_FEATURES", "")
+        d.setVar("DISTRO_FEATURES_DEFAULTS", "alpha beta gamma")
+        d.setVar("DISTRO_FEATURES_OPTED_OUT", "beta")
+        filter_default_features("DISTRO_FEATURES", d)
+        self.assertEqual(d.getVar("DISTRO_FEATURES").strip(), "alpha gamma")
+
+        # opt out of everything
+        d.setVar("DISTRO_FEATURES", "")
+        d.setVar("DISTRO_FEATURES_DEFAULTS", "alpha beta gamma")
+        d.setVar("DISTRO_FEATURES_OPTED_OUT", "gamma alpha beta")
+        filter_default_features("DISTRO_FEATURES", d)
+        self.assertEqual(d.getVar("DISTRO_FEATURES").strip(), "")
+
+        # opt out of something that isn't in our defaults
+        d.setVar("DISTRO_FEATURES", "")
+        d.setVar("DISTRO_FEATURES_DEFAULTS", "alpha beta gamma")
+        d.setVar("DISTRO_FEATURES_OPTED_OUT", "omega")
+        filter_default_features("DISTRO_FEATURES", d)
+        self.assertEqual(d.getVar("DISTRO_FEATURES").strip(), "alpha beta gamma")

-- 
2.43.0