From f3c0ea3664fea45233413ebabe29575b778f55aa Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Wed, 27 Jul 2016 16:47:23 -0500
Subject: [PATCH 1/2] [tools] Fixed precedence issue in cumulative attribute
 set-arithmetic

Basically this:
a | b - c  !=  (a | b) - c
---
 tools/config.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/config.py b/tools/config.py
index c0af0848968..dbc5c0afef4 100644
--- a/tools/config.py
+++ b/tools/config.py
@@ -169,7 +169,8 @@ def strict_cumulative_overrides(self, overrides):
 
     def update_target(self, target):
         setattr(target, self.name, list(
-                set(getattr(target, self.name, [])) | self.additions - self.removals))
+                (set(getattr(target, self.name, [])) | self.additions) - self.removals))
+
 
 
 # 'Config' implements the mbed configuration mechanism

From 63f9b03e3561605637e28ad8c57f8b2beef75293 Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Wed, 27 Jul 2016 18:01:33 -0500
Subject: [PATCH 2/2] [tools] Added test for removing features

---
 tools/test/config_test/test27/lib1/mbed_lib.json |  8 ++++++++
 tools/test/config_test/test27/mbed_app.json      | 11 +++++++++++
 tools/test/config_test/test27/test_data.py       |  8 ++++++++
 3 files changed, 27 insertions(+)
 create mode 100644 tools/test/config_test/test27/lib1/mbed_lib.json
 create mode 100644 tools/test/config_test/test27/mbed_app.json
 create mode 100644 tools/test/config_test/test27/test_data.py

diff --git a/tools/test/config_test/test27/lib1/mbed_lib.json b/tools/test/config_test/test27/lib1/mbed_lib.json
new file mode 100644
index 00000000000..415bbe941fb
--- /dev/null
+++ b/tools/test/config_test/test27/lib1/mbed_lib.json
@@ -0,0 +1,8 @@
+{
+    "name": "lib1",
+    "target_overrides": {
+        "*": {
+            "target.features_remove": ["IPV4"]
+        }
+    }
+}
diff --git a/tools/test/config_test/test27/mbed_app.json b/tools/test/config_test/test27/mbed_app.json
new file mode 100644
index 00000000000..b9695ed925d
--- /dev/null
+++ b/tools/test/config_test/test27/mbed_app.json
@@ -0,0 +1,11 @@
+{
+    "custom_targets": {
+        "test_target": {
+            "core": "Cortex-M0",
+            "extra_labels": [],
+            "features": ["IPV4"],
+            "default_build": "standard"
+        }
+    }
+}
+
diff --git a/tools/test/config_test/test27/test_data.py b/tools/test/config_test/test27/test_data.py
new file mode 100644
index 00000000000..53853318a43
--- /dev/null
+++ b/tools/test/config_test/test27/test_data.py
@@ -0,0 +1,8 @@
+# Testing when adding two features
+
+expected_results = {
+    "test_target": {
+        "desc": "test removing features",
+        "expected_features": []
+    }
+}