Fix rb_interned_str: create strings with BINARY (akak ASCII_8BIT) encoding

[Bug #21842]

The documentation always stated as much, and it's consistent with the
rb_str_* family of functions.

Author: byroot

encoding.c

@@ -1367,7 +1367,7 @@ enc_names_i(st_data_t name, st_data_t idx, st_data_t args)
     VALUE *arg = (VALUE *)args;
 
     if ((int)idx == (int)arg[0]) {
-        VALUE str = rb_interned_str_cstr((char *)name);
+        VALUE str = rb_enc_interned_str_cstr((char *)name, rb_usascii_encoding());
         rb_ary_push(arg[1], str);
     }
     return ST_CONTINUE;
@@ -1873,7 +1873,7 @@ static int
 rb_enc_name_list_i(st_data_t name, st_data_t idx, st_data_t arg)
 {
     VALUE ary = (VALUE)arg;
-    VALUE str = rb_interned_str_cstr((char *)name);
+    VALUE str = rb_enc_interned_str_cstr((char *)name, rb_usascii_encoding());
     rb_ary_push(ary, str);
     return ST_CONTINUE;
 }
@@ -1921,7 +1921,7 @@ rb_enc_aliases_enc_i(st_data_t name, st_data_t orig, st_data_t arg)
         str = rb_fstring_cstr(rb_enc_name(enc));
         rb_ary_store(ary, idx, str);
     }
-    key = rb_interned_str_cstr((char *)name);
+    key = rb_enc_interned_str_cstr((char *)name, rb_usascii_encoding());
     rb_hash_aset(aliases, key, str);
     return ST_CONTINUE;
 }

ext/io/console/console.c

@@ -84,9 +84,9 @@ getattr(int fd, conmode *t)
 static ID id_getc, id_close;
 static ID id_gets, id_flush, id_chomp_bang;
 
-#ifndef HAVE_RB_INTERNED_STR_CSTR
+#ifndef HAVE_RB_ENC_INTERNED_STR_CSTR
 # define rb_str_to_interned_str(str) rb_str_freeze(str)
-# define rb_interned_str_cstr(str) rb_str_freeze(rb_usascii_str_new_cstr(str))
+# define rb_enc_interned_str_cstr(str, enc) rb_str_freeze(rb_usascii_str_new_cstr(str))
 #endif
 
 #if defined HAVE_RUBY_FIBER_SCHEDULER_H
@@ -1897,7 +1897,7 @@ console_ttyname(VALUE io)
 	size_t size = sizeof(termname);
 	int e;
 	if (ttyname_r(fd, tn, size) == 0)
-	    return rb_interned_str_cstr(tn);
+	    return rb_enc_interned_str_cstr(tn, rb_usascii_encoding());
 	if ((e = errno) == ERANGE) {
 	    VALUE s = rb_str_new(0, size);
 	    while (1) {
@@ -1921,7 +1921,7 @@ console_ttyname(VALUE io)
 	    int e = errno;
 	    rb_syserr_fail_str(e, rb_sprintf("ttyname(%d)", fd));
 	}
-	return rb_interned_str_cstr(tn);
+	return rb_enc_interned_str_cstr(tn, rb_usascii_encoding());
     }
 # else
 #   error No ttyname function

ext/io/console/extconf.rb

@@ -9,7 +9,7 @@
 have_func("rb_syserr_new_str(0, Qnil)") or
   abort
 
-have_func("rb_interned_str_cstr")
+have_func("rb_enc_interned_str_cstr")
 have_func("rb_io_path", "ruby/io.h")
 have_func("rb_io_descriptor", "ruby/io.h")
 have_func("rb_io_get_write_io", "ruby/io.h")

gc/default/default.c

@@ -9582,7 +9582,7 @@ rb_gc_impl_init(void)
         VALUE opts;
         /* \GC build options */
         rb_define_const(rb_mGC, "OPTS", opts = rb_ary_new());
-#define OPT(o) if (o) rb_ary_push(opts, rb_interned_str(#o, sizeof(#o) - 1))
+#define OPT(o) if (o) rb_ary_push(opts, rb_enc_interned_str(#o, sizeof(#o) - 1, rb_usascii_encoding()))
         OPT(GC_DEBUG);
         OPT(USE_RGENGC);
         OPT(RGENGC_DEBUG);

string.c

@@ -12709,7 +12709,7 @@ VALUE
 rb_interned_str(const char *ptr, long len)
 {
     struct RString fake_str = {RBASIC_INIT};
-    return register_fstring(setup_fake_str(&fake_str, ptr, len, ENCINDEX_US_ASCII), true, false);
+    return register_fstring(setup_fake_str(&fake_str, ptr, len, ENCINDEX_ASCII_8BIT), true, false);
 }
 
 VALUE