Commit fbe98bb9ed3d ("kconfig: Fix defconfig when one choice menu
selects options that another choice menu depends on") fixed defconfig
when two choices interact (i.e. calculating the visibility of a choice
requires to calculate another choice).

The test code in that commit log was based on the real world example,
and complicated.  So, I shrunk it down to the following:


config MODULES
        def_bool y
        option modules

        prompt "Choice"

config CHOICE_VAL0
        tristate "Choice 0"

config CHOICE_VAL1
        tristate "Choice 1"


        prompt "Another choice"
        depends on CHOICE_VAL0

config DUMMY
        bool "dummy"


Prior to commit fbe98bb9ed3d,

  $ scripts/kconfig/conf --defconfig=defconfig.choice Kconfig.choice

resulted in:

  # CONFIG_CHOICE_VAL1 is not set

where the expected result would be:

  # CONFIG_CHOICE_VAL1 is not set

Roughly, this weird behavior happened like this:

Symbols are calculated a couple of times.  First, all symbols are
calculated in conf_read().  The first 'choice' is evaluated to 'y'
due to the SYMBOL_DEF_USER flag, but sym_calc_choice() clears it
unless all of its choice values are explicitly set by the user.

conf_set_all_new_symbols() clears all SYMBOL_VALID flags.  Then, only
choices are calculated.  Here, the SYMBOL_DEF_USER for the first choice
has been forgotten, so it is evaluated to 'm'.  set_all_choice_values()
sets SYMBOL_DEF_USER again to choice symbols.

When calculating the second choice, due to 'depends on CHOICE_VAL0',
it triggers the calculation of CHOICE_VAL0.  As a result, SYMBOL_VALID
is set for CHOICE_VAL0.

Symbols except choices get the final chance of re-calculation in
conf_write().  In a normal case, CHOICE_VAL0 would be re-calculated,
then the first choice would be indirectly re-calculated with the
SYMBOL_DEF_USER which has been recalled by set_all_choice_values(),
which would be evaluated to 'y'.  But, in this case, CHOICE_VAL0 has
already been marked as SYMBOL_VALID, so this re-calculation does not
happen.  Then, =m from the conf_set_all_new_symbols() phase is written
out to the .config file.

Add a unit test for this naive case.

Signed-off-by: Masahiro Yamada <>
Reviewed-by: Ulf Magnusson <>

Changes in v3:
  - Use def_bool for MODULES

Changes in v2:
  - Newly added

 scripts/kconfig/tests/inter_choice/Kconfig         | 23 ++++++++++++++++++++++
 scripts/kconfig/tests/inter_choice/     | 14 +++++++++++++
 scripts/kconfig/tests/inter_choice/defconfig       |  1 +
 scripts/kconfig/tests/inter_choice/expected_config |  4 ++++
 4 files changed, 42 insertions(+)
 create mode 100644 scripts/kconfig/tests/inter_choice/Kconfig
 create mode 100644 scripts/kconfig/tests/inter_choice/
 create mode 100644 scripts/kconfig/tests/inter_choice/defconfig
 create mode 100644 scripts/kconfig/tests/inter_choice/expected_config

diff --git a/scripts/kconfig/tests/inter_choice/Kconfig 
new file mode 100644
index 0000000..e44449f
--- /dev/null
+++ b/scripts/kconfig/tests/inter_choice/Kconfig
@@ -0,0 +1,23 @@
+config MODULES
+       def_bool y
+       option modules
+       prompt "Choice"
+config CHOICE_VAL0
+       tristate "Choice 0"
+config CHOIVE_VAL1
+       tristate "Choice 1"
+       prompt "Another choice"
+       depends on CHOICE_VAL0
+config DUMMY
+       bool "dummy"
diff --git a/scripts/kconfig/tests/inter_choice/ 
new file mode 100644
index 0000000..5c7fc36
--- /dev/null
+++ b/scripts/kconfig/tests/inter_choice/
@@ -0,0 +1,14 @@
+Do not affect user-assigned choice value by another choice.
+Handling of state flags for choices is complecated.  In old days,
+the defconfig result of a choice could be affected by another choice
+if those choices interact by 'depends on', 'select', etc.
+Related Linux commit: fbe98bb9ed3dae23e320c6b113e35f129538d14a
+def test(conf):
+    assert conf.defconfig('defconfig') == 0
+    assert conf.config_contains('expected_config')
diff --git a/scripts/kconfig/tests/inter_choice/defconfig 
new file mode 100644
index 0000000..162c414
--- /dev/null
+++ b/scripts/kconfig/tests/inter_choice/defconfig
@@ -0,0 +1 @@
diff --git a/scripts/kconfig/tests/inter_choice/expected_config 
new file mode 100644
index 0000000..5dceefb
--- /dev/null
+++ b/scripts/kconfig/tests/inter_choice/expected_config
@@ -0,0 +1,4 @@
+# CONFIG_CHOIVE_VAL1 is not set

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