Fix 'default' on non-visible choice symbols

Previously, 'default CHOICE_SYM [if <cond>]' in a choice would skip any
following 'default' properties if <cond> was non-'n'. However, those
other defaults should still be considered if CHOICE_SYM has visibility
'n'. Previously, we'd immediately fall back to selecting the first
visible symbol in the choice in that case.

get_selection_from_defaults() now exactly mirrors sym_choice_default()
from the C implementation, and got less convoluted too.

Nothing in the kernel defconfigs triggered this.

Add a new test case too.

3 files changed, 38 insertions, 15 deletions

diff --git a/kconfiglib.py b/kconfiglib.py
index 0cab18f..0865176 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -2872,23 +2872,19 @@ class Choice(Item):
         """Like Choice.get_selection(), but acts as if no symbol has been
         selected by the user and no 'optional' flag is in effect."""
 
-        if not self._actual_symbols:
-            return None
-
-        for symbol, cond_expr in self._def_exprs:
-            if self._config._eval_expr(cond_expr) != "n":
-                chosen_symbol = symbol
-                break
-        else:
-            chosen_symbol = self._actual_symbols[0]
+        # Does any 'default SYM [if <cond>]' property apply?
+        for sym, cond_expr in self._def_exprs:
+            if (self._config._eval_expr(cond_expr) != "n" and
+                # Must be visible too
+                _get_visibility(sym) != "n"):
+                return sym
 
-        # Is the chosen symbol visible?
-        if _get_visibility(chosen_symbol) != "n":
-            return chosen_symbol
         # Otherwise, pick the first visible symbol
         for sym in self._actual_symbols:
             if _get_visibility(sym) != "n":
                 return sym
+
+        # Couldn't find a default
         return None
 
     def get_user_selection(self):
diff --git a/tests/Kchoice b/tests/Kchoice
index 1e841ca..e80e222 100644
--- a/tests/Kchoice
+++ b/tests/Kchoice
@@ -75,6 +75,26 @@ config OPT_4
     tristate "OPT_4"
 endchoice
 
+choice DEFAULTS_NOT_VISIBLE
+    bool "defaults not visible"
+    # Skipped due to condition
+    default OPT_6 if n
+    # Skipped because OPT_7 is not visible
+    default OPT_7
+    # This one should apply
+    default OPT_8
+config OPT_5
+    tristate "OPT_5"
+config OPT_6
+    tristate "OPT_6"
+config OPT_7
+    tristate "OPT_7" if n
+config OPT_8
+    tristate "OPT_8"
+config OPT_9
+    tristate "OPT_9"
+endchoice
+
 # Choices without an explicitly specified type should get the type of the first
 # symbol with a type
 
diff --git a/testsuite.py b/testsuite.py
index 9d364c8..870195f 100644
--- a/testsuite.py
+++ b/testsuite.py
@@ -1825,9 +1825,9 @@ def run_selftests():
 
     choice_bool, choice_bool_opt, choice_tristate, choice_tristate_opt, \
       choice_bool_m, choice_tristate_m, choice_defaults, \
-      choice_no_type_bool, choice_no_type_tristate, \
-      choice_missing_member_type_1, choice_missing_member_type_2, \
-      choice_weird_syms = c.get_choices()
+      choice_defaults_not_visible, choice_no_type_bool, \
+      choice_no_type_tristate, choice_missing_member_type_1, \
+      choice_missing_member_type_2, choice_weird_syms = c.get_choices()
 
     for choice in (choice_bool, choice_bool_opt, choice_bool_m,
                    choice_defaults):
@@ -1901,6 +1901,13 @@ def run_selftests():
     verify(choice_defaults.get_selection() is c["OPT_1"],
            "User selection should override defaults")
 
+    verify(choice_defaults_not_visible.get_selection_from_defaults()
+           is c["OPT_8"] and
+           choice_defaults_not_visible.get_selection()
+           is c["OPT_8"],
+           "Non-visible choice symbols should cause the next default to be "
+           "considered")
+
     # Test "y" mode selection
 
     c["MODULES"].set_user_value("y")