Add MenuNode function that returns referenced items

MenuNode.referenced() returns all symbols (and choices, for choice
symbols) referenced in the properties (prompt, defaults, selects,
ranges, etc.) and property conditions of the menu node.

Handy e.g. when generating cross-references.

3 files changed, 110 insertions, 0 deletions

diff --git a/kconfiglib.py b/kconfiglib.py
index 56f9efa..6abb4e6 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -4150,6 +4150,45 @@ class MenuNode(object):
         "ranges"
     )
 
+    def referenced(self):
+        """
+        Returns a set() of all symbols and choices referenced in the properties
+        and property conditions of this menu node.
+
+        Also includes dependencies inherited from surrounding menus and if's.
+        Choices appear in the dependencies of choice symbols.
+        """
+        res = set()
+
+        if self.prompt:
+            res |= expr_items(self.prompt[1])
+
+        if self.item == MENU:
+            res |= expr_items(self.visibility)
+
+        for value, cond in self.defaults:
+            res |= expr_items(value)
+            res |= expr_items(cond)
+
+        for value, cond in self.selects:
+            res.add(value)
+            res |= expr_items(cond)
+
+        for value, cond in self.implies:
+            res.add(value)
+            res |= expr_items(cond)
+
+        for low, high, cond in self.ranges:
+            res.add(low)
+            res.add(high)
+            res |= expr_items(cond)
+
+        # Need this to catch dependencies from a lone 'depends on' when there
+        # are no properties to propagate it to
+        res |= expr_items(self.dep)
+
+        return res
+
     def __repr__(self):
         """
         Returns a string with information about the menu node when it is
diff --git a/tests/Kreferenced b/tests/Kreferenced
new file mode 100644
index 0000000..8dda5a2
--- /dev/null
+++ b/tests/Kreferenced
@@ -0,0 +1,43 @@
+config NO_REFS
+    bool
+
+config JUST_DEPENDS_ON_REFS
+    bool
+    depends on A && B
+
+if A
+
+menu "menu"
+    depends on B
+    visible if C
+    visible if D
+
+config LOTS_OF_REFS
+    bool "lots" if C || D
+    default E || F if G || H
+    default I || J if K || L
+    select M if N || O
+    select P if Q || R
+    imply S if T || U
+    imply V if W || X
+    depends on Y || Z
+
+endmenu
+
+endif
+
+config INT_REFS
+    int "int"
+    range A B if C && D
+    range E F if G && H
+
+choice CHOICE
+    bool "choice"
+
+config CHOICE_REF
+    bool "choice ref"
+
+endchoice
+
+comment "comment"
+    depends on A || B
diff --git a/testsuite.py b/testsuite.py
index 1f1bc32..5c12bc0 100644
--- a/testsuite.py
+++ b/testsuite.py
@@ -1009,8 +1009,36 @@ g
     )
 
 
+    print("Testing MenuNode.referenced()")
+
+    c = Kconfig("Kconfiglib/tests/Kreferenced", warn=False)
+
+    def verify_deps(item, *dep_names):
+        verify_equal(tuple(sorted(item.name for item in item.referenced())),
+                     dep_names)
+
+    verify_deps(c.syms["NO_REFS"].nodes[0], "y")
+
+    verify_deps(c.syms["JUST_DEPENDS_ON_REFS"].nodes[0], "A", "B")
+
+    verify_deps(c.syms["LOTS_OF_REFS"].nodes[0],
+                *(chr(n) for n in range(ord('A'), ord('Z') + 1)))
+
+    verify_deps(c.syms["INT_REFS"].nodes[0],
+                "A", "B", "C", "D", "E", "F", "G", "H", "y")
+
+    verify_deps(c.syms["CHOICE_REF"].nodes[0], "CHOICE")
+
+    verify_deps(c.menus[0], "A", "B", "C", "D")
+
+    verify_deps(c.comments[0], "A", "B")
+
+
     print("Testing split_expr()")
 
+    c = Kconfig("Kconfiglib/tests/empty")
+    c.disable_warnings()
+
     def verify_split(to_split, op, operand_strs):
         # The same hackage as in Kconfig.eval_string()
         c._line = "if " + to_split