kconfig: do not write choice values when their dependency becomes n

Web:        https://git.kernel.org/torvalds/c/cb67ab2cd2b8abd9650292c986c79901e3073a59
Commit:     cb67ab2cd2b8abd9650292c986c79901e3073a59
Parent:     a2b0fe7435faee6f6fbb27409878013bc4727e98
Refname:    refs/heads/master
Author:     Masahiro Yamada <[email protected]>
AuthorDate: Tue Feb 6 09:34:42 2018 +0900
Committer:  Masahiro Yamada <[email protected]>
CommitDate: Fri Feb 9 04:08:05 2018 +0900

    kconfig: do not write choice values when their dependency becomes n
    
    "# CONFIG_... is not set" for choice values are wrongly written into
    the .config file if they are once visible, then become invisible later.
    
      Test case
      ---------
    
    ---------------------------(Kconfig)----------------------------
    config A
            bool "A"
    
    choice
            prompt "Choice ?"
            depends on A
    
    config CHOICE_B
            bool "Choice B"
    
    config CHOICE_C
            bool "Choice C"
    
    endchoice
    ----------------------------------------------------------------
    
    ---------------------------(.config)----------------------------
    CONFIG_A=y
    ----------------------------------------------------------------
    
    With the Kconfig and .config above,
    
      $ make config
      scripts/kconfig/conf  --oldaskconfig Kconfig
      *
      * Linux Kernel Configuration
      *
      A (A) [Y/n] n
      #
      # configuration written to .config
      #
      $ cat .config
      #
      # Automatically generated file; DO NOT EDIT.
      # Linux Kernel Configuration
      #
      # CONFIG_A is not set
      # CONFIG_CHOICE_B is not set
      # CONFIG_CHOICE_C is not set
    
    Here,
    
      # CONFIG_CHOICE_B is not set
      # CONFIG_CHOICE_C is not set
    
    should not be written into the .config file because their dependency
    "depends on A" is unmet.
    
    Currently, there is no code that clears SYMBOL_WRITE of choice values.
    
    Clear SYMBOL_WRITE for all symbols in sym_calc_value(), then set it
    again after calculating visibility.  To simplify the logic, set the
    flag if they have non-n visibility, regardless of types, and regardless
    of whether they are choice values or not.
    
    Signed-off-by: Masahiro Yamada <[email protected]>
    Reviewed-by: Ulf Magnusson <[email protected]>
---
 scripts/kconfig/symbol.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index c9123ed2b791..13f7fdfe328d 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -371,11 +371,13 @@ void sym_calc_value(struct symbol *sym)
 		sym->curr.tri = no;
 		return;
 	}
-	if (!sym_is_choice_value(sym))
-		sym->flags &= ~SYMBOL_WRITE;
+	sym->flags &= ~SYMBOL_WRITE;
 
 	sym_calc_visibility(sym);
 
+	if (sym->visible != no)
+		sym->flags |= SYMBOL_WRITE;
+
 	/* set default if recursively called */
 	sym->curr = newval;
 
@@ -390,7 +392,6 @@ void sym_calc_value(struct symbol *sym)
 				/* if the symbol is visible use the user value
 				 * if available, otherwise try the default value
 				 */
-				sym->flags |= SYMBOL_WRITE;
 				if (sym_has_value(sym)) {
 					newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
 							      sym->visible);
@@ -433,12 +434,9 @@ void sym_calc_value(struct symbol *sym)
 	case S_STRING:
 	case S_HEX:
 	case S_INT:
-		if (sym->visible != no) {
-			sym->flags |= SYMBOL_WRITE;
-			if (sym_has_value(sym)) {
-				newval.val = sym->def[S_DEF_USER].val;
-				break;
-			}
+		if (sym->visible != no && sym_has_value(sym)) {
+			newval.val = sym->def[S_DEF_USER].val;
+			break;
 		}
 		prop = sym_get_default_prop(sym);
 		if (prop) {
--
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