Support 'depends on A if B' syntax

This extends the "depends on" syntax to support conditional dependencies
with "depends on A if B". This is functionally equivalent to
"depends on !B || A" but significantly more readable.

Implementation converts "A if B" to "!B || A" during parsing:
- When B is false, dependency is always satisfied
- When B is true, dependency becomes A

Signed-off-by: Jim Huang <jserv@ccns.ncku.edu.tw>

Author: grahamroff-dev

kconfiglib.py

@@ -3148,6 +3148,22 @@ def _parse_cond(self):
 
         return expr
 
+    def _parse_depends(self):
+        # Parses 'depends on' with optional conditional: 'depends on A if B'
+        # Converts 'A if B' to '!B || A' (if B is false, dependency is satisfied;
+        # if B is true, dependency becomes A)
+
+        expr = self._parse_expr(True)
+
+        if self._check_token(_T_IF):
+            # Transform "A if B" into "!B || A"
+            expr = self._make_or((NOT, self._parse_expr(True)), expr)
+
+        if self._tokens[self._tokens_i] is not None:
+            self._trailing_tokens_error()
+
+        return expr
+
     def _parse_props(self, node):
         # Parses and adds properties to the MenuNode 'node' (type, 'prompt',
         # 'default's, etc.) Properties are later copied up to symbols and
@@ -3183,7 +3199,7 @@ def _parse_props(self, node):
                     self._parse_error("expected 'on' after 'depends'")
 
                 node.dep = self._make_and(node.dep,
-                                          self._expect_expr_and_eol())
+                                          self._parse_depends())
 
             elif t0 is _T_HELP:
                 self._parse_help(node)

tests/Kconddep

@@ -0,0 +1,28 @@
+# Test conditional dependencies: "depends on A if B"
+# Should be equivalent to "depends on !B || A"
+
+config COND_DEP_1
+    bool
+    depends on A if B
+
+config COND_DEP_2
+    bool
+    depends on (C && D) if E
+
+config COND_DEP_MIXED
+    bool
+    depends on A
+    depends on B if C
+    depends on D
+
+# Test with choice
+choice COND_CHOICE
+    bool "conditional choice"
+    depends on X if Y
+endchoice
+
+# Test multiple conditional dependencies combined
+config MULTI_COND
+    bool
+    depends on A if B
+    depends on C if D

testsuite.py

@@ -1324,6 +1324,30 @@ def verify_prompts(items, *expected_prompts):
                  "A || B || C")
 
 
+    print("Testing conditional dependencies (depends on A if B)")
+
+    c = Kconfig("Kconfiglib/tests/Kconddep")
+
+    # "depends on A if B" should become "!B || A"
+    verify_equal(expr_str(c.syms["COND_DEP_1"].direct_dep), "!B || A")
+
+    # "depends on (C && D) if E" should become "!E || (C && D)"
+    verify_equal(expr_str(c.syms["COND_DEP_2"].direct_dep), "!E || (C && D)")
+
+    # Multiple depends combined: "depends on A", "depends on B if C", "depends on D"
+    # Should become: "A && (!C || B) && D"
+    verify_equal(expr_str(c.syms["COND_DEP_MIXED"].direct_dep),
+                 "A && (!C || B) && D")
+
+    # Test with choice
+    verify_equal(expr_str(c.named_choices["COND_CHOICE"].direct_dep), "!Y || X")
+
+    # Multiple conditional dependencies: "depends on A if B" and "depends on C if D"
+    # Should become: "(!B || A) && (!D || C)"
+    verify_equal(expr_str(c.syms["MULTI_COND"].direct_dep),
+                 "(!B || A) && (!D || C)")
+
+
     print("Testing expr_items()")
 
     c = Kconfig("Kconfiglib/tests/Kexpr_items")