Add valid property to sources

Signed-off-by: Nikola Forró <[email protected]>

specfile/sources.py

@@ -66,6 +66,12 @@ def comments(self) -> Comments:
         """List of comments associated with the source."""
         ...
 
+    @property
+    @abstractmethod
+    def valid(self) -> bool:
+        """Whether the source is not located in a false branch of a condition."""
+        ...
+
 
 class TagSource(Source):
     """Class that represents a source backed by a spec file tag."""
@@ -161,6 +167,11 @@ def comments(self) -> Comments:
         """List of comments associated with the source."""
         return self._tag.comments
 
+    @property
+    def valid(self) -> bool:
+        """Whether the source is not located in a false branch of a condition."""
+        return self._tag.valid
+
 
 class ListSource(Source):
     """Class that represents a source backed by a line in a %sourcelist section."""
@@ -224,6 +235,11 @@ def comments(self) -> Comments:
         """List of comments associated with the source."""
         return self._source.comments
 
+    @property
+    def valid(self) -> bool:
+        """Whether the source is not located in a false branch of a condition."""
+        return self._source.valid
+
 
 class Sources(collections.abc.MutableSequence):
     """Class that represents a sequence of all sources."""