special no inheritance mark

examples/no_inherit/.fmf/version

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

examples/no_inherit/a/main.fmf

@@ -0,0 +1,2 @@
+/inherited:
+  special!: 2

examples/no_inherit/main.fmf

@@ -0,0 +1,6 @@
+special!: 1
+x: X
+/a:
+  b: b
+  x!: abc
+  /inherited:

fmf/base.py

@@ -226,8 +226,14 @@ 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 not key.endswith('!'):
+                print(f"no inherit {value}")
+                data[key] = copy.deepcopy(value)
+
         self._merge_special(data, self.data)
         self.data = data
 

tests/unit/test_no_inheritance_mark.py

@@ -0,0 +1,24 @@
+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(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)