[PATCH v2 2/2] kconfig: remove 'optional' property support

From: Masahiro Yamada
Date: Mon Apr 22 2024 - 12:43:41 EST


The 'choice' statement is primarily used to exclusively select one
option, but the 'optional' property allows all entries to be disabled.

In the following example, both A and B can be disabled simultaneously:

choice
prompt "choose A, B, or nothing"
optional

config A
bool "A"

config B
bool "B"

endchoice

You can achieve the equivalent outcome by other means.

A common solution is to add another option to guard the choice block.
In the following example, you can set ENABLE_A_B_CHOICE=n to disable
the entire choice block:

choice
prompt "choose A or B"
depends on ENABLE_A_B_CHOICE

config A
bool "A"

config B
bool "B"

endchoice

Another approach is to insert one more entry as a place-holder:

choice
prompt "choose A, B, or disable both"

config A
bool "A"

config B
bool "B"

config DISABLE_A_AND_B
bool "choose this to disable both A and B"

endchoice

Some real examples are DEBUG_INFO_NONE, INITRAMFS_COMPRESSION_NONE,
LTO_NONE, etc.

The 'optional' property is even more unnecessary for a tristate choice.

Without the 'optional' property, you can disable A and B; you can set
'm' in the choice prompt, and disable A and B individually:

choice
prompt "choose one built-in or make them modular"

config A
tristate "A"

config B
tristate "B"

endchoice

In conclusion, the 'optional' property was unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

(no changes since v1)

Documentation/kbuild/kconfig-language.rst | 3 ---
scripts/kconfig/confdata.c | 5 +---
scripts/kconfig/expr.h | 1 -
scripts/kconfig/gconf.c | 2 --
scripts/kconfig/lexer.l | 1 -
scripts/kconfig/lkc.h | 5 ----
scripts/kconfig/menu.c | 12 +++------
scripts/kconfig/parser.y | 9 -------
scripts/kconfig/tests/choice/Kconfig | 26 -------------------
.../tests/choice/allmod_expected_config | 4 ---
.../tests/choice/allyes_expected_config | 4 ---
.../tests/choice/oldask0_expected_stdout | 2 --
scripts/kconfig/tests/choice/oldask1_config | 1 -
.../tests/choice/oldask1_expected_stdout | 6 -----
14 files changed, 5 insertions(+), 76 deletions(-)

diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 79ac2e8184f6..555c2f839969 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -410,9 +410,6 @@ to be set to 'm'. This can be used if multiple drivers for a single
hardware exists and only a single driver can be compiled/loaded into
the kernel, but all drivers can be compiled as modules.

-A choice accepts another option "optional", which allows to set the
-choice to 'n' and no entry needs to be selected.
-
comment::

"comment" <prompt>
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index a86e71bab5fa..bcce87658998 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -810,9 +810,6 @@ int conf_write_defconfig(const char *filename)
/*
* If symbol is a choice value and equals to the
* default for a choice - skip.
- * But only if value is bool and equal to "y" and
- * choice is not "optional".
- * (If choice is "optional" then all values can be "n")
*/
if (sym_is_choice_value(sym)) {
struct symbol *cs;
@@ -820,7 +817,7 @@ int conf_write_defconfig(const char *filename)

cs = prop_get_symbol(sym_get_choice_prop(sym));
ds = sym_choice_default(cs);
- if (!sym_is_optional(cs) && sym == ds) {
+ if (sym == ds) {
if ((sym->type == S_BOOLEAN) &&
sym_get_tristate_value(sym) == yes)
continue;
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 68b3dd65cb08..f646a98de006 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -132,7 +132,6 @@ struct symbol {
#define SYMBOL_CHECK 0x0008 /* used during dependency checking */
#define SYMBOL_CHOICEVAL 0x0020 /* used as a value in a choice block */
#define SYMBOL_VALID 0x0080 /* set when symbol.curr is calculated */
-#define SYMBOL_OPTIONAL 0x0100 /* choice is optional - values can be 'n' */
#define SYMBOL_WRITE 0x0200 /* write symbol to file (KCONFIG_CONFIG) */
#define SYMBOL_CHANGED 0x0400 /* ? */
#define SYMBOL_WRITTEN 0x0800 /* track info to avoid double-write to .config */
diff --git a/scripts/kconfig/gconf.c b/scripts/kconfig/gconf.c
index 74f193272a00..13e2449ac83f 100644
--- a/scripts/kconfig/gconf.c
+++ b/scripts/kconfig/gconf.c
@@ -87,8 +87,6 @@ static const char *dbg_sym_flags(int val)
strcat(buf, "choiceval/");
if (val & SYMBOL_VALID)
strcat(buf, "valid/");
- if (val & SYMBOL_OPTIONAL)
- strcat(buf, "optional/");
if (val & SYMBOL_WRITE)
strcat(buf, "write/");
if (val & SYMBOL_CHANGED)
diff --git a/scripts/kconfig/lexer.l b/scripts/kconfig/lexer.l
index 89544c3a1a29..8dd597c4710d 100644
--- a/scripts/kconfig/lexer.l
+++ b/scripts/kconfig/lexer.l
@@ -120,7 +120,6 @@ n [A-Za-z0-9_-]
"menuconfig" return T_MENUCONFIG;
"modules" return T_MODULES;
"on" return T_ON;
-"optional" return T_OPTIONAL;
"prompt" return T_PROMPT;
"range" return T_RANGE;
"select" return T_SELECT;
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 5e27432e4939..64dfc354dd5c 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -138,11 +138,6 @@ static inline bool sym_is_choice_value(struct symbol *sym)
return sym->flags & SYMBOL_CHOICEVAL ? true : false;
}

-static inline bool sym_is_optional(struct symbol *sym)
-{
- return sym->flags & SYMBOL_OPTIONAL ? true : false;
-}
-
static inline bool sym_has_value(struct symbol *sym)
{
return sym->flags & SYMBOL_DEF_USER ? true : false;
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index fe6af8700622..e01b9ee87c05 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -593,15 +593,11 @@ static void _menu_finalize(struct menu *parent, bool inside_choice)
}

/*
- * For non-optional choices, add a reverse dependency (corresponding to
- * a select) of '<visibility> && m'. This prevents the user from
- * setting the choice mode to 'n' when the choice is visible.
- *
- * This would also work for non-choice symbols, but only non-optional
- * choices clear SYMBOL_OPTIONAL as of writing. Choices are implemented
- * as a type of symbol.
+ * For choices, add a reverse dependency (corresponding to a select) of
+ * '<visibility> && m'. This prevents the user from setting the choice
+ * mode to 'n' when the choice is visible.
*/
- if (sym && !sym_is_optional(sym) && parent->prompt) {
+ if (sym && sym_is_choice(sym) && parent->prompt) {
sym->rev_dep.expr = expr_alloc_or(sym->rev_dep.expr,
expr_alloc_and(parent->prompt->visible.expr,
expr_alloc_symbol(&symbol_mod)));
diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
index b95993ff3837..69dc0c098acb 100644
--- a/scripts/kconfig/parser.y
+++ b/scripts/kconfig/parser.y
@@ -69,7 +69,6 @@ struct menu *current_menu, *current_entry;
%token T_MODULES
%token T_ON
%token T_OPEN_PAREN
-%token T_OPTIONAL
%token T_PLUS_EQUAL
%token T_PROMPT
%token T_RANGE
@@ -140,7 +139,6 @@ stmt_list_in_choice:

config_entry_start: T_CONFIG nonconst_symbol T_EOL
{
- $2->flags |= SYMBOL_OPTIONAL;
menu_add_entry($2);
printd(DEBUG_PARSE, "%s:%d:config %s\n", cur_filename, cur_lineno, $2->name);
};
@@ -152,7 +150,6 @@ config_stmt: config_entry_start config_option_list

menuconfig_entry_start: T_MENUCONFIG nonconst_symbol T_EOL
{
- $2->flags |= SYMBOL_OPTIONAL;
menu_add_entry($2);
printd(DEBUG_PARSE, "%s:%d:menuconfig %s\n", cur_filename, cur_lineno, $2->name);
};
@@ -272,12 +269,6 @@ choice_option: logic_type prompt_stmt_opt T_EOL
printd(DEBUG_PARSE, "%s:%d:type(%u)\n", cur_filename, cur_lineno, $1);
};

-choice_option: T_OPTIONAL T_EOL
-{
- current_entry->sym->flags |= SYMBOL_OPTIONAL;
- printd(DEBUG_PARSE, "%s:%d:optional\n", cur_filename, cur_lineno);
-};
-
choice_option: T_DEFAULT nonconst_symbol if_expr T_EOL
{
menu_add_symbol(P_DEFAULT, $2, $3);
diff --git a/scripts/kconfig/tests/choice/Kconfig b/scripts/kconfig/tests/choice/Kconfig
index 0930eb65e932..8cdda40868a1 100644
--- a/scripts/kconfig/tests/choice/Kconfig
+++ b/scripts/kconfig/tests/choice/Kconfig
@@ -17,19 +17,6 @@ config BOOL_CHOICE1

endchoice

-choice
- prompt "optional boolean choice"
- optional
- default OPT_BOOL_CHOICE1
-
-config OPT_BOOL_CHOICE0
- bool "choice 0"
-
-config OPT_BOOL_CHOICE1
- bool "choice 1"
-
-endchoice
-
choice
prompt "tristate choice"
default TRI_CHOICE1
@@ -41,16 +28,3 @@ config TRI_CHOICE1
tristate "choice 1"

endchoice
-
-choice
- prompt "optional tristate choice"
- optional
- default OPT_TRI_CHOICE1
-
-config OPT_TRI_CHOICE0
- tristate "choice 0"
-
-config OPT_TRI_CHOICE1
- tristate "choice 1"
-
-endchoice
diff --git a/scripts/kconfig/tests/choice/allmod_expected_config b/scripts/kconfig/tests/choice/allmod_expected_config
index f1f5dcdb7923..d1f51651740c 100644
--- a/scripts/kconfig/tests/choice/allmod_expected_config
+++ b/scripts/kconfig/tests/choice/allmod_expected_config
@@ -1,9 +1,5 @@
CONFIG_MODULES=y
# CONFIG_BOOL_CHOICE0 is not set
CONFIG_BOOL_CHOICE1=y
-# CONFIG_OPT_BOOL_CHOICE0 is not set
-CONFIG_OPT_BOOL_CHOICE1=y
CONFIG_TRI_CHOICE0=m
CONFIG_TRI_CHOICE1=m
-CONFIG_OPT_TRI_CHOICE0=m
-CONFIG_OPT_TRI_CHOICE1=m
diff --git a/scripts/kconfig/tests/choice/allyes_expected_config b/scripts/kconfig/tests/choice/allyes_expected_config
index e5a062a1157c..8a76c1816893 100644
--- a/scripts/kconfig/tests/choice/allyes_expected_config
+++ b/scripts/kconfig/tests/choice/allyes_expected_config
@@ -1,9 +1,5 @@
CONFIG_MODULES=y
# CONFIG_BOOL_CHOICE0 is not set
CONFIG_BOOL_CHOICE1=y
-# CONFIG_OPT_BOOL_CHOICE0 is not set
-CONFIG_OPT_BOOL_CHOICE1=y
# CONFIG_TRI_CHOICE0 is not set
CONFIG_TRI_CHOICE1=y
-# CONFIG_OPT_TRI_CHOICE0 is not set
-CONFIG_OPT_TRI_CHOICE1=y
diff --git a/scripts/kconfig/tests/choice/oldask0_expected_stdout b/scripts/kconfig/tests/choice/oldask0_expected_stdout
index b251bba9698b..d2257db46423 100644
--- a/scripts/kconfig/tests/choice/oldask0_expected_stdout
+++ b/scripts/kconfig/tests/choice/oldask0_expected_stdout
@@ -3,8 +3,6 @@ boolean choice
1. choice 0 (BOOL_CHOICE0) (NEW)
> 2. choice 1 (BOOL_CHOICE1) (NEW)
choice[1-2?]:
-optional boolean choice [N/y/?] (NEW)
tristate choice [M/y/?] (NEW)
choice 0 (TRI_CHOICE0) [N/m/?] (NEW)
choice 1 (TRI_CHOICE1) [N/m/?] (NEW)
-optional tristate choice [N/m/y/?] (NEW)
diff --git a/scripts/kconfig/tests/choice/oldask1_config b/scripts/kconfig/tests/choice/oldask1_config
index b67bfe3c641f..0f417856c81c 100644
--- a/scripts/kconfig/tests/choice/oldask1_config
+++ b/scripts/kconfig/tests/choice/oldask1_config
@@ -1,2 +1 @@
# CONFIG_MODULES is not set
-CONFIG_OPT_BOOL_CHOICE0=y
diff --git a/scripts/kconfig/tests/choice/oldask1_expected_stdout b/scripts/kconfig/tests/choice/oldask1_expected_stdout
index c2125e9bf96a..ffa20ad7f38e 100644
--- a/scripts/kconfig/tests/choice/oldask1_expected_stdout
+++ b/scripts/kconfig/tests/choice/oldask1_expected_stdout
@@ -3,13 +3,7 @@ boolean choice
1. choice 0 (BOOL_CHOICE0) (NEW)
> 2. choice 1 (BOOL_CHOICE1) (NEW)
choice[1-2?]:
-optional boolean choice [Y/n/?] (NEW)
-optional boolean choice
-> 1. choice 0 (OPT_BOOL_CHOICE0)
- 2. choice 1 (OPT_BOOL_CHOICE1) (NEW)
-choice[1-2?]:
tristate choice
1. choice 0 (TRI_CHOICE0) (NEW)
> 2. choice 1 (TRI_CHOICE1) (NEW)
choice[1-2?]:
-optional tristate choice [N/y/?]
--
2.40.1