[pull] master from ruby:master

array.c

@@ -1740,32 +1740,29 @@ rb_ary_entry(VALUE ary, long offset)
     return rb_ary_entry_internal(ary, offset);
 }
 
-static VALUE
-rb_ary_subseq_step(VALUE ary, long beg, long len, long step)
+static long
+ary_subseq_len(VALUE ary, long beg, long len)
 {
-    VALUE klass;
     long alen = RARRAY_LEN(ary);
 
-    if (beg > alen) return Qnil;
-    if (beg < 0 || len < 0) return Qnil;
+    if (beg > alen) return -1;
+    if (beg < 0 || len < 0) return -1;
 
     if (alen < len || alen < beg + len) {
         len = alen - beg;
     }
-    klass = rb_cArray;
-    if (len == 0) return ary_new(klass, 0);
-    if (step == 0)
-        rb_raise(rb_eArgError, "slice step cannot be zero");
-    if (step == 1)
-        return ary_make_partial(ary, klass, beg, len);
-    else
-        return ary_make_partial_step(ary, klass, beg, len, step);
+    ASSUME(len >= 0);
+    return len;
 }
 
 VALUE
 rb_ary_subseq(VALUE ary, long beg, long len)
 {
-    return rb_ary_subseq_step(ary, beg, len, 1);
+    const VALUE klass = rb_cArray;
+    len = ary_subseq_len(ary, beg, len);
+    if (len < 0) return Qnil;
+    if (len == 0) return ary_new(klass, 0);
+    return ary_make_partial(ary, klass, beg, len);
 }
 
 static VALUE rb_ary_aref2(VALUE ary, VALUE b, VALUE e);
@@ -1913,6 +1910,7 @@ VALUE
 rb_ary_aref1(VALUE ary, VALUE arg)
 {
     long beg, len, step;
+    const VALUE klass = rb_cArray;
 
     /* special case - speeding up */
     if (FIXNUM_P(arg)) {
@@ -1925,7 +1923,11 @@ rb_ary_aref1(VALUE ary, VALUE arg)
       case Qnil:
         return Qnil;
       default:
-        return rb_ary_subseq_step(ary, beg, len, step);
+        if (step == 0) rb_raise(rb_eArgError, "slice step cannot be zero");
+        len = ary_subseq_len(ary, beg, len);
+        if (len == 0) return ary_new(klass, 0);
+        if (step == 1) return ary_make_partial(ary, klass, beg, len);
+        return ary_make_partial_step(ary, klass, beg, len, step);
     }
 
     return rb_ary_entry(ary, NUM2LONG(arg));

benchmark/symbol_empty.yml

@@ -0,0 +1,8 @@
+prelude: |
+  sym0  = :""
+  sym8  = :abcdefgh
+  GC.disable
+benchmark:
+  symbol_empty-0:  sym0.empty?
+  symbol_empty-8:  sym8.empty?
+loop_count: 20000000

common.mk

@@ -414,6 +414,8 @@ $(LIBRUBY_A):	$(LIBRUBY_A_OBJS) $(MAINOBJ) $(INITOBJS) $(ARCHFILE)
 
 $(LIBRUBY_SO):	$(OBJS) $(DLDOBJS) $(LIBRUBY_A) $(PREP) $(BUILTIN_ENCOBJS)
 
+$(LIBRUBY_A) $(LIBRUBY_SO): $(LIBRUBY_SO_UPDATE)
+
 $(LIBRUBY_EXTS):
 	@$(NULLCMD) > $@
 

ext/psych/extconf.rb

@@ -2,6 +2,28 @@
 # frozen_string_literal: true
 require 'mkmf'
 
+# Experimental, opt-in libfyaml backend.  Only used when psych is built with
+# --enable-libfyaml.  Without the flag nothing below changes and the default
+# libyaml backend is built exactly as before.
+if enable_config("libfyaml", false)
+  if $mswin or $mingw or $cygwin
+    abort "The libfyaml backend (--enable-libfyaml) is not supported on Windows"
+  end
+  unless pkg_config('libfyaml')
+    abort "libfyaml was requested with --enable-libfyaml but was not found via pkg-config"
+  end
+  # libfyaml 0.8 and earlier crash psych's emitter, so require a known-good
+  # version rather than building something that segfaults at runtime.
+  pkgconfig = ENV["PKG_CONFIG"] || "pkg-config"
+  unless system(pkgconfig, "--atleast-version=0.9", "libfyaml")
+    abort "The libfyaml backend requires libfyaml 0.9 or newer"
+  end
+  $defs << "-DPSYCH_USE_LIBFYAML"
+
+  create_makefile 'psych'
+  return
+end
+
 if $mswin or $mingw or $cygwin
   $CPPFLAGS << " -DYAML_DECLARE_STATIC"
 end

ext/psych/lib/psych/scalar_scanner.rb

@@ -24,6 +24,18 @@ class ScalarScanner
                          |[-+]?(?:0|[1-9](?:[0-9]|,[0-9]|_[0-9])*) (?# base 10)
                          |[-+]?0x[_,]*[0-9a-fA-F][0-9a-fA-F_,]*    (?# base 16))$/x
 
+    # YAML 1.1 treats yes/no/on/off as booleans in addition to true/false,
+    # while YAML 1.2's core schema only recognizes true/false.  The default
+    # libyaml backend keeps the 1.1 set for backward compatibility; the
+    # experimental libfyaml backend follows 1.2.
+    if defined?(Psych::BACKEND) && Psych::BACKEND == 'libfyaml'
+      BOOLEAN_TRUE  = /^true$/i
+      BOOLEAN_FALSE = /^false$/i
+    else
+      BOOLEAN_TRUE  = /^(yes|true|on)$/i
+      BOOLEAN_FALSE = /^(no|false|off)$/i
+    end
+
     attr_reader :class_loader
 
     # Create a new scanner
@@ -48,9 +60,9 @@ def tokenize string
           string
         elsif string == '~' || string.match?(/^null$/i)
           nil
-        elsif string.match?(/^(yes|true|on)$/i)
+        elsif string.match?(BOOLEAN_TRUE)
           true
-        elsif string.match?(/^(no|false|off)$/i)
+        elsif string.match?(BOOLEAN_FALSE)
           false
         else
           string

ext/psych/psych.c

@@ -2,14 +2,25 @@
 
 /* call-seq: Psych.libyaml_version
  *
- * Returns the version of libyaml being used
+ * Returns the version of the underlying YAML library as a three-element
+ * array. This is libyaml by default. On the experimental libfyaml backend,
+ * where libyaml is not linked, it reports the libfyaml version instead.
  */
 static VALUE libyaml_version(VALUE module)
 {
     int major, minor, patch;
     VALUE list[3];
 
+#ifdef PSYCH_USE_LIBFYAML
+    /* Experimental libfyaml backend: there is no libyaml linked in.  Report
+     * the libfyaml version so callers still receive a 3-element version. */
+    const struct fy_version *v = fy_version_default();
+    major = v ? v->major : 0;
+    minor = v ? v->minor : 0;
+    patch = 0;
+#else
     yaml_get_version(&major, &minor, &patch);
+#endif
 
     list[0] = INT2NUM(major);
     list[1] = INT2NUM(minor);
@@ -18,6 +29,20 @@ static VALUE libyaml_version(VALUE module)
     return rb_ary_new4((long)3, list);
 }
 
+#ifdef PSYCH_USE_LIBFYAML
+/* call-seq: Psych.libfyaml_version
+ *
+ * Returns the libfyaml version string. This method is only defined when
+ * psych was built with the experimental libfyaml backend
+ * (+--enable-libfyaml+).
+ */
+static VALUE libfyaml_version(VALUE module)
+{
+    const char *v = fy_library_version();
+    return v ? rb_usascii_str_new2(v) : Qnil;
+}
+#endif
+
 VALUE mPsych;
 
 void Init_psych(void)
@@ -29,6 +54,13 @@ void Init_psych(void)
 
     rb_define_singleton_method(mPsych, "libyaml_version", libyaml_version, 0);
 
+#ifdef PSYCH_USE_LIBFYAML
+    rb_define_singleton_method(mPsych, "libfyaml_version", libfyaml_version, 0);
+    rb_define_const(mPsych, "BACKEND", rb_usascii_str_new2("libfyaml"));
+#else
+    rb_define_const(mPsych, "BACKEND", rb_usascii_str_new2("libyaml"));
+#endif
+
     Init_psych_parser();
     Init_psych_emitter();
     Init_psych_to_ruby();

ext/psych/psych.h

@@ -4,7 +4,11 @@
 #include <ruby.h>
 #include <ruby/encoding.h>
 
+#ifdef PSYCH_USE_LIBFYAML
+#include <libfyaml.h>
+#else
 #include <yaml.h>
+#endif
 
 #include <psych_parser.h>
 #include <psych_emitter.h>

ext/psych/psych_emitter.c

@@ -1,5 +1,7 @@
 #include <psych.h>
 
+#ifndef PSYCH_USE_LIBFYAML
+
 #if !defined(RARRAY_CONST_PTR)
 #define RARRAY_CONST_PTR(s) (const VALUE *)RARRAY_PTR(s)
 #endif
@@ -587,3 +589,5 @@ void Init_psych_emitter(void)
     id_indentation = rb_intern("indentation");
     id_canonical   = rb_intern("canonical");
 }
+
+#endif /* PSYCH_USE_LIBFYAML */