special no inheritance mark

examples/no_inherit/.fmf/version

@@ -0,0 +1 @@
+1

examples/no_inherit/a/main.fmf

@@ -0,0 +1,6 @@
+/inherited:
+  special!: 2
+/stop_inherit:
+  c!: stop
+  /no_c:
+    test: x

examples/no_inherit/main.fmf

@@ -0,0 +1,7 @@
+special!: 1
+x: X
+c: cc
+/a:
+  b: b
+  x!: abc
+  /inherited:

fmf/base.py

@@ -58,6 +58,9 @@ def __init__(self, data, name=None, parent=None):
         # (needed to prevent removing nodes with an empty dict).
         self._updated = False
 
+        # stop inheritance item
+        self.stop_inheritance_list = list()
+
         # Store symlinks in while walking tree in grow() to detect
         # symlink loops
         if parent is None:
@@ -218,6 +221,16 @@ def init(path):
                 root, error))
         return root
 
+    def _stop_inherit_item(self, item: str):
+        if item in self.stop_inheritance_list:
+            print(f"{item} already")
+            return item[:-1]
+        elif item.endswith('!'):
+            print(f"{item} ADD")
+            self.stop_inheritance_list.append(item)
+            return item[:-1]
+        return None
+
     def merge(self, parent=None):
         """ Merge parent data """
         # Check parent, append source files
@@ -226,10 +239,16 @@ def merge(self, parent=None):
         if parent is None:
             return
         self.sources = parent.sources + self.sources
-        # Merge child data with parent data
-        data = copy.deepcopy(parent.data)
+        data = {}
+        # Merge child data with parent da
+        for key, value in parent.data.items():
+            # avoid to copy data if marked as stop inheritance
+            if key + "!" not in parent.stop_inheritance_list:
+                data[key] = copy.deepcopy(value)
         self._merge_special(data, self.data)
-        self.data = data
+        for key, value in data.items():
+            item = self._stop_inherit_item(key) or key
+            self.data[item] = data[key]
 
     def inherit(self):
         """ Apply inheritance """
@@ -268,7 +287,8 @@ def update(self, data):
                 self.child(name, value)
             # Update regular attributes
             else:
-                self.data[key] = value
+                item = self._stop_inherit_item(key) or key
+                self.data[item] = data[key]
         log.debug("Data for '{0}' updated.".format(self))
         log.data(pretty(self.data))
 

tests/unit/test_no_inheritance_mark.py

@@ -0,0 +1,32 @@
+import os
+import unittest
+
+import fmf
+
+# Prepare path to examples
+PATH = os.path.dirname(os.path.realpath(__file__))
+EXAMPLES = PATH + "/../../examples/"
+
+
+class TestNoInheritance(unittest.TestCase):
+    """ Verify storing modifed data to disk """
+
+    def setUp(self):
+        self.path = EXAMPLES + "no_inherit"
+        self.tree = fmf.Tree(self.path)
+
+    def test_base(self):
+        root_item = self.tree.find('/')
+        a_item = self.tree.find('/a')
+        inherite_item = self.tree.find('/a/inherited')
+        self.assertIn("special", root_item.data)
+        self.assertIn("special", inherite_item.data)
+        self.assertNotIn("special", a_item.data)
+
+    def test_undefine(self):
+        c_item = self.tree.find("/a/stop_inherit")
+        no_c_item = self.tree.find("/a/stop_inherit/no_c")
+        self.assertNotIn("special", c_item.data)
+        self.assertNotIn("special", no_c_item.data)
+        self.assertIn("c", c_item.data)
+        self.assertNotIn("c", no_c_item.data)