[pull] master from ruby:master

internal/string.h

@@ -126,6 +126,7 @@ VALUE rb_obj_as_string_result(VALUE str, VALUE obj);
 VALUE rb_str_opt_plus(VALUE x, VALUE y);
 VALUE rb_str_new_owned(char *ptr, long len, long capa, int encindex);
 VALUE rb_str_concat_literals(size_t num, const VALUE *strary);
+VALUE rb_str_format_ary(int argc, const VALUE *argv, VALUE fmt, VALUE ary);
 VALUE rb_str_eql(VALUE str1, VALUE str2);
 VALUE rb_id_quote_unprintable(ID);
 VALUE rb_sym_proc_call(ID mid, int argc, const VALUE *argv, int kw_splat, VALUE passed_proc);

sprintf.c

@@ -110,15 +110,26 @@ expand_result(VALUE result, long bsiz, long blen, long l)
     blen += (l);\
 } while (0)
 
+static void
+format_args_check(VALUE ary, int argc, const VALUE *argv)
+{
+    if (!RTEST(ary)) return;
+    if (RARRAY_LEN(ary) != argc || RARRAY_CONST_PTR(ary) != argv) {
+        rb_raise(rb_eRuntimeError, "array modified during formatting");
+    }
+}
+
 #define GETARG() (!UNDEF_P(nextvalue) ? nextvalue : \
                   GETNEXTARG())
 
 #define GETNEXTARG() ( \
     check_next_arg(posarg, nextarg), \
+    (RTEST(ary) ? (format_args_check(ary, argc0, argv0), 0) : 0), \
     (posarg = nextarg++, GETNTHARG(posarg)))
 
 #define GETPOSARG(n) ( \
     check_pos_arg(posarg, (n)), \
+    (RTEST(ary) ? (format_args_check(ary, argc0, argv0), 0) : 0), \
     (posarg = -1, GETNTHARG(n)))
 
 #define GETNTHARG(nth) \
@@ -224,7 +235,7 @@ rb_f_sprintf(int argc, const VALUE *argv)
 }
 
 VALUE
-rb_str_format(int argc, const VALUE *argv, VALUE fmt)
+rb_str_format_ary(int argc, const VALUE *argv, VALUE fmt, VALUE ary)
 {
     enum {default_float_precision = 6};
     rb_encoding *enc;
@@ -268,6 +279,10 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
                                ENC_CODERANGE_BROKEN : (coderange = cr))); \
         } \
     } while (0)
+
+    const int argc0 = argc;
+    const VALUE *argv0 = argv;
+
     ++argc;
     --argv;
     StringValue(fmt);
@@ -945,6 +960,7 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
     rb_str_tmp_frozen_release(orig, fmt);
     /* XXX - We cannot validate the number of arguments if (digit)$ style used.
      */
+    format_args_check(ary, argc0, argv0);
     if (posarg >= 0 && nextarg < argc && !(argc == 2 && RB_TYPE_P(argv[1], T_HASH))) {
         const char *mesg = "too many arguments for format string";
         if (RTEST(ruby_verbose)) rb_warn("%s", mesg);
@@ -954,6 +970,12 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt)
     return result;
 }
 
+VALUE
+rb_str_format(int argc, const VALUE *argv, VALUE fmt)
+{
+    return rb_str_format_ary(argc, argv, fmt, Qfalse);
+}
+
 static char *
 fmt_setup(char *buf, size_t size, int c, int flags, int width, int prec)
 {

string.c

@@ -2695,7 +2695,7 @@ rb_str_format_m(VALUE str, VALUE arg)
     VALUE tmp = rb_check_array_type(arg);
 
     if (!NIL_P(tmp)) {
-        VALUE result = rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
+        VALUE result = rb_str_format_ary(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str, tmp);
         RB_GC_GUARD(tmp);
         return result;
     }

test/ruby/test_sprintf.rb

@@ -289,6 +289,20 @@ def test_invalid
     end
   end
 
+  def test_modify_argument_array
+    count = 1_000
+    obj = Object.new
+    ary = [obj, *Array.new(count - 1) { "x" }]
+    obj.define_singleton_method(:to_s) do
+      ary.replace([])
+      "X"
+    end
+    str = "%s" * count
+    assert_raise_with_message(RuntimeError, /array modified during formatting/) do
+      str % ary
+    end
+  end
+
   def test_float
     assert_equal("36893488147419111424",
                  sprintf("%20.0f", 36893488147419107329.0))

win32/Makefile.sub

@@ -357,6 +357,17 @@ CPPFLAGS = $(DEFS) $(ARCHDEFS) $(CPPFLAGS)
 CPPFLAGS = -DDISABLE_RUBYGEMS $(CPPFLAGS)
 !endif
 
+# https://learn.microsoft.com/en-us/cpp/build/reference/zc-preprocessor?view=msvc-170
+!if $(MSC_VER) >= 1925
+# maybe >= 1926?
+# https://devblogs.microsoft.com/cppblog/announcing-full-support-for-a-c-c-conformant-preprocessor-in-msvc/
+CPPFLAGS = -Zc:preprocessor $(CPPFLAGS)
+!elseif $(MSC_VER) >= 1915
+CPPFLAGS = -experimental:preprocessor $(CPPFLAGS)
+!else
+! error C99 conformant preprocessor is required
+!endif
+
 POSTLINK =
 DLDFLAGS = $(LDFLAGS) -dll
 MAINLIBS = $(LIBS)
@@ -1323,10 +1334,10 @@ modular-gc-precheck:
 
 {$(srcdir)/coroutine/win32}.asm{coroutine/win32}.obj:
 	$(ECHO) assembling $(<:\=/)
-	$(Q) $(AS) $(ASFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(<:\=/)
+	$(Q) $(AS) $(ASFLAGS) $(COUTFLAG)$@ -c $(<:\=/)
 {$(srcdir)/coroutine/win64}.asm{coroutine/win64}.obj:
 	$(ECHO) assembling $(<:\=/)
-	$(Q) $(AS) $(ASFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(<:\=/)
+	$(Q) $(AS) $(ASFLAGS) $(COUTFLAG)$@ -c $(<:\=/)
 {$(srcdir)/coroutine/arm64}.asm{coroutine/arm64}.obj:
 	$(ECHO) assembling $(<:\=/)
 	$(Q) $(AS) $(ASFLAGS) -o $@ $(<:\=/)