kconfig: loop as long as we changed some symbols in randconfig

Because of choice-in-a-choice constructs, it can happen that not all
symbols are assigned a value during randconfig, leading in rare cases
to this situation:

    ---8<--- choice-in-choice.in
    choice
        bool "A/B/C"
    config A
        bool "A"

    config B
        bool "B"
    if B
    choice
        bool "E/F"
    config E
        bool "E"
    config F
        bool "F"
    endchoice
    endif # B

    config C
        bool "C"
    endchoice
    ---8<---

    $ ./scripts/kconfig/conf --randconfig choice-in-choice.in
    [--SNIP--]
    $ ./scripts/kconfig/conf --silentoldconfig choice-in-choice.in </dev/null
    [--SNIP--]
    A/B/C
      1. A (A)
    > 2. B (B)
      3. C (C)
    choice[1-3]: 2
      E/F
      > 1. E (E) (NEW)
        2. F (F) (NEW)
      choice[1-2]: aborted!

    Console input/output is redirected. Run 'make oldconfig' to update
    configuration.

Fix this by looping in randconfig for as long as some symbol gets assigned
a value.

Note: this was spotted with the USB EHCI Debug Device Gadget (USB_G_DBGP),
which uses this choice-in-a-choice construct, and exhibits this problem.
The example above is just a stripped-down minimalist test-case.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

scripts/kconfig/conf.c

@@ -654,7 +654,8 @@ int main(int ac, char **av)
 		conf_set_all_new_symbols(def_default);
 		break;
 	case randconfig:
-		conf_set_all_new_symbols(def_random);
+		/* Really nothing to do in this loop */
+		while (conf_set_all_new_symbols(def_random)) ;
 		break;
 	case defconfig:
 		conf_set_all_new_symbols(def_default);

scripts/kconfig/confdata.c

@@ -1040,7 +1040,7 @@ void conf_set_changed_callback(void (*fn)(void))
 	conf_changed_callback = fn;
 }
 
-static void randomize_choice_values(struct symbol *csym)
+static bool randomize_choice_values(struct symbol *csym)
 {
 	struct property *prop;
 	struct symbol *sym;
@@ -1053,7 +1053,7 @@ static void randomize_choice_values(struct symbol *csym)
 	 * In both cases stop.
 	 */
 	if (csym->curr.tri != yes)
-		return;
+		return false;
 
 	prop = sym_get_choice_prop(csym);
 
@@ -1084,6 +1084,8 @@ static void randomize_choice_values(struct symbol *csym)
 	csym->flags |= SYMBOL_DEF_USER;
 	/* clear VALID to get value calculated */
 	csym->flags &= ~(SYMBOL_VALID);
+
+	return true;
 }
 
 void set_all_choice_values(struct symbol *csym)
@@ -1106,7 +1108,7 @@ void set_all_choice_values(struct symbol *csym)
 	csym->flags &= ~(SYMBOL_VALID | SYMBOL_NEED_SET_CHOICE_VALUES);
 }
 
-void conf_set_all_new_symbols(enum conf_def_mode mode)
+bool conf_set_all_new_symbols(enum conf_def_mode mode)
 {
 	struct symbol *sym, *csym;
 	int i, cnt, pby, pty, ptm;	/* pby: probability of boolean  = y
@@ -1154,6 +1156,7 @@ void conf_set_all_new_symbols(enum conf_def_mode mode)
 			exit( 1 );
 		}
 	}
+	bool has_changed = false;
 
 	for_all_symbols(i, sym) {
 		if (sym_has_value(sym) || (sym->flags & SYMBOL_VALID))
@@ -1161,6 +1164,7 @@ void conf_set_all_new_symbols(enum conf_def_mode mode)
 		switch (sym_get_type(sym)) {
 		case S_BOOLEAN:
 		case S_TRISTATE:
+			has_changed = true;
 			switch (mode) {
 			case def_yes:
 				sym->def[S_DEF_USER].tri = yes;
@@ -1219,6 +1223,12 @@ void conf_set_all_new_symbols(enum conf_def_mode mode)
 
 		sym_calc_value(csym);
 		if (mode == def_random)
-			randomize_choice_values(csym);
+			has_changed = randomize_choice_values(csym);
+		else {
+			set_all_choice_values(csym);
+			has_changed = true;
 		}
+	}
+
+	return has_changed;
 }

scripts/kconfig/lkc.h

@@ -86,7 +86,7 @@ const char *conf_get_autoconfig_name(void);
 char *conf_get_default_confname(void);
 void sym_set_change_count(int count);
 void sym_add_change_count(int count);
-void conf_set_all_new_symbols(enum conf_def_mode mode);
+bool conf_set_all_new_symbols(enum conf_def_mode mode);
 void set_all_choice_values(struct symbol *csym);
 
 struct conf_printer {