Extend the "depends on" syntax to support conditional dependencies
using "depends on X if Y". While functionally equivalent to "depends
on X || (Y == n)", "depends on X if Y" is much more readable and
makes the kconfig language uniform in supporting the "if <expr>"
suffix.
This also improves readability for "optional" dependencies, which
are the subset of conditional dependencies where X is Y.
Previously such optional dependencies had to be expressed as
the counterintuitive "depends on X || !X", now this can be
represented as "depends on X if X".
The change is implemented by converting the "X if Y" syntax into the
"X || (Y == n)" syntax during "depends on" token processing.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
[Graham Roff: Rewrote commit message, updated patch, added tests]
Signed-off-by: Graham Roff <grahamr@qti.qualcomm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20251215-kconfig_conditional_deps-v3-1-59519af0a5df@qti.qualcomm.com
[nathan: Minor adjustments to spacing]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This is a shorthand notation for a type definition plus a value.
Optionally dependencies for this default value can be added with "if".
-- dependencies: "depends on" <expr>
+- dependencies: "depends on" <expr> ["if" <expr>]
This defines a dependency for this menu entry. If multiple
dependencies are defined, they are connected with '&&'. Dependencies
bool "foo"
default y
+ The dependency definition itself may be conditional by appending "if"
+ followed by an expression. For example::
+
+ config FOO
+ tristate
+ depends on BAR if BAZ
+
+ meaning that FOO is constrained by the value of BAR only if BAZ is
+ also set.
+
- reverse dependencies: "select" <symbol> ["if" <expr>]
While normal dependencies reduce the upper limit of a symbol (see
or build cleanly with that module disabled, but cause a link failure
when trying to use that loadable module from a built-in driver.
-The most common way to express this optional dependency in Kconfig logic
-uses the slightly counterintuitive::
+The recommended way to express this optional dependency in Kconfig logic
+uses the conditional form::
+
+ config FOO
+ tristate "Support for foo hardware"
+ depends on BAR if BAR
+
+This slightly counterintuitive style is also widely used::
config FOO
tristate "Support for foo hardware"
struct menu *menu_add_menu(void);
void menu_end_menu(void);
void menu_add_entry(struct symbol *sym, enum menu_type type);
-void menu_add_dep(struct expr *dep);
+void menu_add_dep(struct expr *dep, struct expr *cond);
void menu_add_visibility(struct expr *dep);
struct property *menu_add_prompt(enum prop_type type, const char *prompt,
struct expr *dep);
return e;
}
-void menu_add_dep(struct expr *dep)
+void menu_add_dep(struct expr *dep, struct expr *cond)
{
+ if (cond) {
+ /*
+ * We have "depends on X if Y" and we want:
+ * Y != n --> X
+ * Y == n --> y
+ * That simplifies to: (X || (Y == n))
+ */
+ dep = expr_alloc_or(dep,
+ expr_trans_compare(cond, E_EQUAL, &symbol_no));
+ }
current_entry->dep = expr_alloc_and(current_entry->dep, dep);
}
{
printd(DEBUG_PARSE, "%s:%d:if\n", cur_filename, cur_lineno);
menu_add_entry(NULL, M_IF);
- menu_add_dep($2);
+ menu_add_dep($2, NULL);
$$ = menu_add_menu();
};
/* depends option */
-depends: T_DEPENDS T_ON expr T_EOL
+depends: T_DEPENDS T_ON expr if_expr T_EOL
{
- menu_add_dep($3);
+ menu_add_dep($3, $4);
printd(DEBUG_PARSE, "%s:%d:depends on\n", cur_filename, cur_lineno);
};
--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+# Test Kconfig file for conditional dependencies.
+
+# Enable module support for tristate testing
+config MODULES
+ bool "Enable loadable module support"
+ modules
+ default y
+
+config FOO
+ bool "FOO symbol"
+
+config BAR
+ bool "BAR symbol"
+
+config TEST_BASIC
+ bool "Test basic conditional dependency"
+ depends on FOO if BAR
+ default y
+
+config TEST_COMPLEX
+ bool "Test complex conditional dependency"
+ depends on (FOO && BAR) if (FOO || BAR)
+ default y
+
+config BAZ
+ tristate "BAZ symbol"
+
+config TEST_OPTIONAL
+ tristate "Test simple optional dependency"
+ depends on BAZ if BAZ
+ default y
--- /dev/null
+# SPDX-License-Identifier: GPL-2.0
+"""
+Correctly handle conditional dependencies.
+"""
+
+def test(conf):
+ assert conf.oldconfig('test_config1') == 0
+ assert conf.config_matches('expected_config1')
+
+ assert conf.oldconfig('test_config2') == 0
+ assert conf.config_matches('expected_config2')
+
+ assert conf.oldconfig('test_config3') == 0
+ assert conf.config_matches('expected_config3')
--- /dev/null
+#
+# Automatically generated file; DO NOT EDIT.
+# Main menu
+#
+CONFIG_MODULES=y
+CONFIG_FOO=y
+CONFIG_BAR=y
+CONFIG_TEST_BASIC=y
+CONFIG_TEST_COMPLEX=y
+CONFIG_BAZ=m
+CONFIG_TEST_OPTIONAL=m
--- /dev/null
+#
+# Automatically generated file; DO NOT EDIT.
+# Main menu
+#
+CONFIG_MODULES=y
+# CONFIG_FOO is not set
+CONFIG_BAR=y
+CONFIG_BAZ=y
+CONFIG_TEST_OPTIONAL=y
--- /dev/null
+#
+# Automatically generated file; DO NOT EDIT.
+# Main menu
+#
+CONFIG_MODULES=y
+# CONFIG_FOO is not set
+# CONFIG_BAR is not set
+CONFIG_TEST_BASIC=y
+CONFIG_TEST_COMPLEX=y
+# CONFIG_BAZ is not set
+CONFIG_TEST_OPTIONAL=y
--- /dev/null
+# Basic check that everything can be configured if selected.
+CONFIG_FOO=y
+CONFIG_BAR=y
+CONFIG_BAZ=m
+# Ensure that TEST_OPTIONAL=y with BAZ=m is converted to TEST_OPTIONAL=m
+CONFIG_TEST_OPTIONAL=y
--- /dev/null
+# If FOO is not selected, then TEST_BASIC should fail the conditional
+# dependency since BAR is set.
+# TEST_COMPLEX will fail dependency as it depends on both FOO and BAR
+# if either of those is selected.
+CONFIG_FOO=n
+CONFIG_BAR=y
+CONFIG_BAZ=y
--- /dev/null
+# If FOO is not selected, but BAR is also not selected, then TEST_BASIC
+# should pass since the dependency on FOO is conditional on BAR.
+# TEST_COMPLEX should be also set since neither FOO nor BAR are selected
+# so it has no dependencies.
+CONFIG_FOO=n
+CONFIG_BAR=n
projects / thirdparty / kernel / linux.git / commitdiff
