18 files changed, 313 insertions, 112 deletions

diff --git a/spec/ruby/core/array/pack/a_spec.rb b/spec/ruby/core/array/pack/a_spec.rb
index 7af7a16c68..f4a40502c2 100644
--- a/spec/ruby/core/array/pack/a_spec.rb
+++ b/spec/ruby/core/array/pack/a_spec.rb
@@ -12,6 +12,17 @@ describe "Array#pack with format 'A'" do
   it_behaves_like :array_pack_string, 'A'
   it_behaves_like :array_pack_taint, 'A'
 
+  it "calls #to_str to convert an Object to a String" do
+    obj = mock("pack A string")
+    obj.should_receive(:to_str).and_return("``abcdef")
+    [obj].pack("A*").should == "``abcdef"
+  end
+
+  it "will not implicitly convert a number to a string" do
+    -> { [0].pack('A') }.should raise_error(TypeError)
+    -> { [0].pack('a') }.should raise_error(TypeError)
+  end
+
   it "adds all the bytes to the output when passed the '*' modifier" do
     ["abc"].pack("A*").should == "abc"
   end
diff --git a/spec/ruby/core/array/pack/b_spec.rb b/spec/ruby/core/array/pack/b_spec.rb
index 872c1b88d5..ec82b7d1ab 100644
--- a/spec/ruby/core/array/pack/b_spec.rb
+++ b/spec/ruby/core/array/pack/b_spec.rb
@@ -13,11 +13,16 @@ describe "Array#pack with format 'B'" do
   it_behaves_like :array_pack_taint, 'B'
 
   it "calls #to_str to convert an Object to a String" do
-    obj = mock("pack H string")
+    obj = mock("pack B string")
     obj.should_receive(:to_str).and_return("``abcdef")
     [obj].pack("B*").should == "\x2a"
   end
 
+  it "will not implicitly convert a number to a string" do
+    -> { [0].pack('B') }.should raise_error(TypeError)
+    -> { [0].pack('b') }.should raise_error(TypeError)
+  end
+
   it "encodes one bit for each character starting with the most significant bit" do
     [ [["0"], "\x00"],
       [["1"], "\x80"]
diff --git a/spec/ruby/core/array/pack/buffer_spec.rb b/spec/ruby/core/array/pack/buffer_spec.rb
index ecb40bfd06..f1206efb3e 100644
--- a/spec/ruby/core/array/pack/buffer_spec.rb
+++ b/spec/ruby/core/array/pack/buffer_spec.rb
@@ -13,13 +13,13 @@ describe "Array#pack with :buffer option" do
   it "adds result at the end of buffer content" do
     n = [ 65, 66, 67 ] # result without buffer is "ABC"
 
-    buffer = ""
+    buffer = +""
     n.pack("ccc", buffer: buffer).should == "ABC"
 
-    buffer = "123"
+    buffer = +"123"
     n.pack("ccc", buffer: buffer).should == "123ABC"
 
-    buffer = "12345"
+    buffer = +"12345"
     n.pack("ccc", buffer: buffer).should == "12345ABC"
   end
 
@@ -31,19 +31,19 @@ describe "Array#pack with :buffer option" do
   context "offset (@) is specified" do
     it 'keeps buffer content if it is longer than offset' do
       n = [ 65, 66, 67 ]
-      buffer = "123456"
+      buffer = +"123456"
       n.pack("@3ccc", buffer: buffer).should == "123ABC"
     end
 
     it "fills the gap with \\0 if buffer content is shorter than offset" do
       n = [ 65, 66, 67 ]
-      buffer = "123"
+      buffer = +"123"
       n.pack("@6ccc", buffer: buffer).should == "123\0\0\0ABC"
     end
 
     it 'does not keep buffer content if it is longer than offset + result' do
       n = [ 65, 66, 67 ]
-      buffer = "1234567890"
+      buffer = +"1234567890"
       n.pack("@3ccc", buffer: buffer).should == "123ABC"
     end
   end
diff --git a/spec/ruby/core/array/pack/c_spec.rb b/spec/ruby/core/array/pack/c_spec.rb
index 7200830331..ac133ff9b6 100644
--- a/spec/ruby/core/array/pack/c_spec.rb
+++ b/spec/ruby/core/array/pack/c_spec.rb
@@ -45,8 +45,20 @@ describe :array_pack_8bit, shared: true do
     [1, 2, 3, 4, 5].pack(pack_format('*')).should == "\x01\x02\x03\x04\x05"
   end
 
-  it "ignores NULL bytes between directives" do
-    [1, 2, 3].pack(pack_format("\000", 2)).should == "\x01\x02"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [1, 2, 3].pack(pack_format("\000", 2)).should == "\x01\x02"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [1, 2, 3].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
diff --git a/spec/ruby/core/array/pack/h_spec.rb b/spec/ruby/core/array/pack/h_spec.rb
index 85a875fc8b..2c1dac8d4a 100644
--- a/spec/ruby/core/array/pack/h_spec.rb
+++ b/spec/ruby/core/array/pack/h_spec.rb
@@ -18,6 +18,11 @@ describe "Array#pack with format 'H'" do
     [obj].pack("H").should == "\xa0"
   end
 
+  it "will not implicitly convert a number to a string" do
+    -> { [0].pack('H') }.should raise_error(TypeError)
+    -> { [0].pack('h') }.should raise_error(TypeError)
+  end
+
   it "encodes the first character as the most significant nibble when passed no count modifier" do
     ["ab"].pack("H").should == "\xa0"
   end
diff --git a/spec/ruby/core/array/pack/m_spec.rb b/spec/ruby/core/array/pack/m_spec.rb
index 2b1a84abca..c6364af12d 100644
--- a/spec/ruby/core/array/pack/m_spec.rb
+++ b/spec/ruby/core/array/pack/m_spec.rb
@@ -80,8 +80,16 @@ describe "Array#pack with format 'M'" do
     ].should be_computed_by(:pack, "M")
   end
 
-  it "encodes a tab followed by a newline with an encoded newline" do
+  it "encodes a tab at the end of a line with an encoded newline" do
+    ["\t"].pack("M").should == "\t=\n"
     ["\t\n"].pack("M").should == "\t=\n\n"
+    ["abc\t\nxyz"].pack("M").should == "abc\t=\n\nxyz=\n"
+  end
+
+  it "encodes a space at the end of a line with an encoded newline" do
+    [" "].pack("M").should == " =\n"
+    [" \n"].pack("M").should == " =\n\n"
+    ["abc \nxyz"].pack("M").should == "abc =\n\nxyz=\n"
   end
 
   it "encodes 127..255 in hex format" do
diff --git a/spec/ruby/core/array/pack/p_spec.rb b/spec/ruby/core/array/pack/p_spec.rb
index d7dff8a4da..b023bf9110 100644
--- a/spec/ruby/core/array/pack/p_spec.rb
+++ b/spec/ruby/core/array/pack/p_spec.rb
@@ -15,18 +15,6 @@ describe "Array#pack with format 'P'" do
     ["hello"].pack("P").unpack("P5").should == ["hello"]
   end
 
-  ruby_version_is ''...'2.7' do
-    it "taints the input string" do
-      input_string = "hello"
-      [input_string].pack("P")
-      input_string.tainted?.should be_true
-    end
-
-    it "does not taint the output string in normal cases" do
-      ["hello"].pack("P").tainted?.should be_false
-    end
-  end
-
   it "with nil gives a null pointer" do
     [nil].pack("P").unpack("J").should == [0]
   end
@@ -44,18 +32,6 @@ describe "Array#pack with format 'p'" do
     ["hello"].pack("p").unpack("p").should == ["hello"]
   end
 
-  ruby_version_is ''...'2.7' do
-    it "taints the input string" do
-      input_string = "hello"
-      [input_string].pack("p")
-      input_string.tainted?.should be_true
-    end
-
-    it "does not taint the output string in normal cases" do
-      ["hello"].pack("p").tainted?.should be_false
-    end
-  end
-
   it "with nil gives a null pointer" do
     [nil].pack("p").unpack("J").should == [0]
   end
diff --git a/spec/ruby/core/array/pack/shared/basic.rb b/spec/ruby/core/array/pack/shared/basic.rb
index 9061273ad6..5e3eea55f9 100644
--- a/spec/ruby/core/array/pack/shared/basic.rb
+++ b/spec/ruby/core/array/pack/shared/basic.rb
@@ -27,17 +27,47 @@ describe :array_pack_basic_non_float, shared: true do
     [@obj, @obj].pack("a \t\n\v\f\r"+pack_format).should be_an_instance_of(String)
   end
 
+  it "ignores comments in the format string" do
+    # 2 additional directives ('a') are required for the X directive
+    [@obj, @obj, @obj, @obj].pack("aa #{pack_format} # some comment \n#{pack_format}").should be_an_instance_of(String)
+  end
+
+  ruby_version_is ""..."3.2" do
+    it "warns in verbose mode that a directive is unknown" do
+      # additional directive ('a') is required for the X directive
+      -> { [@obj, @obj].pack("a R" + pack_format) }.should complain(/unknown pack directive 'R'/, verbose: true)
+      -> { [@obj, @obj].pack("a 0" + pack_format) }.should complain(/unknown pack directive '0'/, verbose: true)
+      -> { [@obj, @obj].pack("a :" + pack_format) }.should complain(/unknown pack directive ':'/, verbose: true)
+    end
+  end
+
+  ruby_version_is "3.2"..."3.3" do
+    # https://bugs.ruby-lang.org/issues/19150
+    # NOTE: it's just a plan of the Ruby core team
+    it "warns that a directive is unknown" do
+      # additional directive ('a') is required for the X directive
+      -> { [@obj, @obj].pack("a R" + pack_format) }.should complain(/unknown pack directive 'R'/)
+      -> { [@obj, @obj].pack("a 0" + pack_format) }.should complain(/unknown pack directive '0'/)
+      -> { [@obj, @obj].pack("a :" + pack_format) }.should complain(/unknown pack directive ':'/)
+    end
+  end
+
+  ruby_version_is "3.3" do
+    # https://bugs.ruby-lang.org/issues/19150
+    # NOTE: Added this case just to not forget about the decision in the ticket
+    it "raise ArgumentError when a directive is unknown" do
+      # additional directive ('a') is required for the X directive
+      -> { [@obj, @obj].pack("a R" + pack_format) }.should raise_error(ArgumentError)
+      -> { [@obj, @obj].pack("a 0" + pack_format) }.should raise_error(ArgumentError)
+      -> { [@obj, @obj].pack("a :" + pack_format) }.should raise_error(ArgumentError)
+    end
+  end
+
   it "calls #to_str to coerce the directives string" do
     d = mock("pack directive")
     d.should_receive(:to_str).and_return("x"+pack_format)
     [@obj, @obj].pack(d).should be_an_instance_of(String)
   end
-
-  ruby_version_is ''...'2.7' do
-    it "taints the output string if the format string is tainted" do
-      [@obj, @obj].pack("x"+pack_format.taint).tainted?.should be_true
-    end
-  end
 end
 
 describe :array_pack_basic_float, shared: true do
@@ -45,17 +75,15 @@ describe :array_pack_basic_float, shared: true do
     [9.3, 4.7].pack(" \t\n\v\f\r"+pack_format).should be_an_instance_of(String)
   end
 
+  it "ignores comments in the format string" do
+    [9.3, 4.7].pack(pack_format + "# some comment \n" + pack_format).should be_an_instance_of(String)
+  end
+
   it "calls #to_str to coerce the directives string" do
     d = mock("pack directive")
     d.should_receive(:to_str).and_return("x"+pack_format)
     [1.2, 4.7].pack(d).should be_an_instance_of(String)
   end
-
-  ruby_version_is ''...'2.7' do
-    it "taints the output string if the format string is tainted" do
-      [3.2, 2.8].pack("x"+pack_format.taint).tainted?.should be_true
-    end
-  end
 end
 
 describe :array_pack_no_platform, shared: true do
diff --git a/spec/ruby/core/array/pack/shared/float.rb b/spec/ruby/core/array/pack/shared/float.rb
index c6b194007f..1780d7635e 100644
--- a/spec/ruby/core/array/pack/shared/float.rb
+++ b/spec/ruby/core/array/pack/shared/float.rb
@@ -25,8 +25,20 @@ describe :array_pack_float_le, shared: true do
     [2.9, 1.4, 8.2].pack(pack_format("*")).should == "\x9a\x999@33\xb3?33\x03A"
   end
 
-  it "ignores NULL bytes between directives" do
-    [5.3, 9.2].pack(pack_format("\000", 2)).should == "\x9a\x99\xa9@33\x13A"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [5.3, 9.2].pack(pack_format("\000", 2)).should == "\x9a\x99\xa9@33\x13A"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [5.3, 9.2].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -53,6 +65,14 @@ describe :array_pack_float_le, shared: true do
   it "encodes a negative Float outside the range of a single precision float" do
     [-1e150].pack(pack_format).should == "\x00\x00\x80\xff"
   end
+
+  it "encodes a bignum as a float" do
+    [2 ** 65].pack(pack_format).should == [(2 ** 65).to_f].pack(pack_format)
+  end
+
+  it "encodes a rational as a float" do
+    [Rational(3, 4)].pack(pack_format).should == [Rational(3, 4).to_f].pack(pack_format)
+  end
 end
 
 describe :array_pack_float_be, shared: true do
@@ -66,6 +86,11 @@ describe :array_pack_float_be, shared: true do
 
   it "converts an Integer to a Float" do
     [8].pack(pack_format).should == "A\x00\x00\x00"
+    [bignum_value].pack(pack_format).should == "_\x80\x00\x00"
+  end
+
+  it "converts a Rational to a Float" do
+    [Rational(8)].pack(pack_format).should == "A\x00\x00\x00"
   end
 
   it "raises a TypeError if passed a String representation of a floating point number" do
@@ -80,8 +105,20 @@ describe :array_pack_float_be, shared: true do
     [2.9, 1.4, 8.2].pack(pack_format("*")).should == "@9\x99\x9a?\xb333A\x0333"
   end
 
-  it "ignores NULL bytes between directives" do
-    [5.3, 9.2].pack(pack_format("\000", 2)).should == "@\xa9\x99\x9aA\x1333"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [5.3, 9.2].pack(pack_format("\000", 2)).should == "@\xa9\x99\x9aA\x1333"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [5.3, 9.2].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -121,6 +158,11 @@ describe :array_pack_double_le, shared: true do
 
   it "converts an Integer to a Float" do
     [8].pack(pack_format).should == "\x00\x00\x00\x00\x00\x00\x20@"
+    [bignum_value].pack(pack_format).should == "\x00\x00\x00\x00\x00\x00\xF0C"
+  end
+
+  it "converts a Rational to a Float" do
+    [Rational(8)].pack(pack_format).should == "\x00\x00\x00\x00\x00\x00 @"
   end
 
   it "raises a TypeError if passed a String representation of a floating point number" do
@@ -135,8 +177,20 @@ describe :array_pack_double_le, shared: true do
     [2.9, 1.4, 8.2].pack(pack_format("*")).should == "333333\x07@ffffff\xf6?ffffff\x20@"
   end
 
-  it "ignores NULL bytes between directives" do
-    [5.3, 9.2].pack(pack_format("\000", 2)).should == "333333\x15@ffffff\x22@"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [5.3, 9.2].pack(pack_format("\000", 2)).should == "333333\x15@ffffff\x22@"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [5.3, 9.2].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -194,8 +248,20 @@ describe :array_pack_double_be, shared: true do
     [2.9, 1.4, 8.2].pack(pack_format("*")).should == "@\x07333333?\xf6ffffff@\x20ffffff"
   end
 
-  it "ignores NULL bytes between directives" do
-    [5.3, 9.2].pack(pack_format("\000", 2)).should == "@\x15333333@\x22ffffff"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [5.3, 9.2].pack(pack_format("\000", 2)).should == "@\x15333333@\x22ffffff"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [5.3, 9.2].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
diff --git a/spec/ruby/core/array/pack/shared/integer.rb b/spec/ruby/core/array/pack/shared/integer.rb
index 6592f85022..fd21b25b19 100644
--- a/spec/ruby/core/array/pack/shared/integer.rb
+++ b/spec/ruby/core/array/pack/shared/integer.rb
@@ -41,9 +41,21 @@ describe :array_pack_16bit_le, shared: true do
     str.should == "\x78\x65\xcd\xab\x21\x43"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
-    str.should == "\x78\x65\xcd\xab"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+        str.should == "\x78\x65\xcd\xab"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -93,9 +105,21 @@ describe :array_pack_16bit_be, shared: true do
     str.should == "\x65\x78\xab\xcd\x43\x21"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
-    str.should == "\x65\x78\xab\xcd"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+        str.should == "\x65\x78\xab\xcd"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -145,9 +169,21 @@ describe :array_pack_32bit_le, shared: true do
     str.should == "\x78\x65\x43\x12\xcd\xab\xf0\xde\x21\x43\x65\x78"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
-    str.should == "\x78\x65\x43\x12\xcd\xab\xf0\xde"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+        str.should == "\x78\x65\x43\x12\xcd\xab\xf0\xde"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -197,9 +233,21 @@ describe :array_pack_32bit_be, shared: true do
     str.should == "\x12\x43\x65\x78\xde\xf0\xab\xcd\x78\x65\x43\x21"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
-    str.should == "\x12\x43\x65\x78\xde\xf0\xab\xcd"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+        str.should == "\x12\x43\x65\x78\xde\xf0\xab\xcd"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0x1243_6578, 0xdef0_abcd].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -309,9 +357,21 @@ describe :array_pack_64bit_le, shared: true do
     str.should == "\x56\x78\x12\x34\xcd\xab\xf0\xde\xf0\xde\xba\xdc\x21\x43\x65\x78"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
-    str.should == "\x56\x78\x12\x34\xcd\xab\xf0\xde\xf0\xde\xba\xdc\x21\x43\x65\x78"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
+        str.should == "\x56\x78\x12\x34\xcd\xab\xf0\xde\xf0\xde\xba\xdc\x21\x43\x65\x78"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
@@ -369,9 +429,21 @@ describe :array_pack_64bit_be, shared: true do
     str.should == "\xde\xf0\xab\xcd\x34\x12\x78\x56\x78\x65\x43\x21\xdc\xba\xde\xf0"
   end
 
-  it "ignores NULL bytes between directives" do
-    str = [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
-    str.should == "\xde\xf0\xab\xcd\x34\x12\x78\x56\x78\x65\x43\x21\xdc\xba\xde\xf0"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        str = [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
+        str.should == "\xde\xf0\xab\xcd\x34\x12\x78\x56\x78\x65\x43\x21\xdc\xba\xde\xf0"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [0xdef0_abcd_3412_7856, 0x7865_4321_dcba_def0].pack(pack_format("\000", 2))
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
diff --git a/spec/ruby/core/array/pack/shared/numeric_basic.rb b/spec/ruby/core/array/pack/shared/numeric_basic.rb
index 7c36ba4a32..545e215e64 100644
--- a/spec/ruby/core/array/pack/shared/numeric_basic.rb
+++ b/spec/ruby/core/array/pack/shared/numeric_basic.rb
@@ -37,8 +37,14 @@ describe :array_pack_float, shared: true do
     -> { ["a"].pack(pack_format) }.should raise_error(TypeError)
   end
 
-  it "raises a TypeError when the object does not respond to #to_f" do
-    obj = mock('not an float')
+  it "raises a TypeError when the object is not Numeric" do
+    obj = Object.new
+    -> { [obj].pack(pack_format) }.should raise_error(TypeError, /can't convert Object into Float/)
+  end
+
+  it "raises a TypeError when the Numeric object does not respond to #to_f" do
+    klass = Class.new(Numeric)
+    obj = klass.new
     -> { [obj].pack(pack_format) }.should raise_error(TypeError)
   end
 end
diff --git a/spec/ruby/core/array/pack/shared/string.rb b/spec/ruby/core/array/pack/shared/string.rb
index 8c82e8c617..2f70dc3951 100644
--- a/spec/ruby/core/array/pack/shared/string.rb
+++ b/spec/ruby/core/array/pack/shared/string.rb
@@ -40,7 +40,7 @@ describe :array_pack_string, shared: true do
     f = pack_format("*")
     [ [["\u{3042 3044 3046 3048}", 0x2000B].pack(f+"U"),       Encoding::BINARY],
       [["abcde\xd1", "\xFF\xFe\x81\x82"].pack(f+"u"),          Encoding::BINARY],
-      [["a".force_encoding("ascii"), "\xFF\xFe\x81\x82"].pack(f+"u"), Encoding::BINARY],
+      [["a".dup.force_encoding("ascii"), "\xFF\xFe\x81\x82"].pack(f+"u"), Encoding::BINARY],
       # under discussion [ruby-dev:37294]
       [["\u{3042 3044 3046 3048}", 1].pack(f+"N"),             Encoding::BINARY]
     ].should be_computed_by(:encoding)
diff --git a/spec/ruby/core/array/pack/shared/taint.rb b/spec/ruby/core/array/pack/shared/taint.rb
index 565f04b8b9..2c2b011c34 100644
--- a/spec/ruby/core/array/pack/shared/taint.rb
+++ b/spec/ruby/core/array/pack/shared/taint.rb
@@ -1,35 +1,2 @@
 describe :array_pack_taint, shared: true do
-  ruby_version_is ''...'2.7' do
-    it "returns a tainted string when a pack argument is tainted" do
-      ["abcd".taint, 0x20].pack(pack_format("3C")).tainted?.should be_true
-    end
-
-    it "does not return a tainted string when the array is tainted" do
-      ["abcd", 0x20].taint.pack(pack_format("3C")).tainted?.should be_false
-    end
-
-    it "returns a tainted string when the format is tainted" do
-      ["abcd", 0x20].pack(pack_format("3C").taint).tainted?.should be_true
-    end
-
-    it "returns a tainted string when an empty format is tainted" do
-      ["abcd", 0x20].pack("".taint).tainted?.should be_true
-    end
-
-    it "returns a untrusted string when the format is untrusted" do
-      ["abcd", 0x20].pack(pack_format("3C").untrust).untrusted?.should be_true
-    end
-
-    it "returns a untrusted string when the empty format is untrusted" do
-      ["abcd", 0x20].pack("".untrust).untrusted?.should be_true
-    end
-
-    it "returns a untrusted string when a pack argument is untrusted" do
-      ["abcd".untrust, 0x20].pack(pack_format("3C")).untrusted?.should be_true
-    end
-
-    it "returns a trusted string when the array is untrusted" do
-      ["abcd", 0x20].untrust.pack(pack_format("3C")).untrusted?.should be_false
-    end
-  end
 end
diff --git a/spec/ruby/core/array/pack/shared/unicode.rb b/spec/ruby/core/array/pack/shared/unicode.rb
index dd0f8b38aa..4d8eaef323 100644
--- a/spec/ruby/core/array/pack/shared/unicode.rb
+++ b/spec/ruby/core/array/pack/shared/unicode.rb
@@ -67,8 +67,20 @@ describe :array_pack_unicode, shared: true do
     -> { [obj].pack("U") }.should raise_error(TypeError)
   end
 
-  it "ignores NULL bytes between directives" do
-    [1, 2, 3].pack("U\x00U").should == "\x01\x02"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [1, 2, 3].pack("U\x00U").should == "\x01\x02"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [1, 2, 3].pack("U\x00U")
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
diff --git a/spec/ruby/core/array/pack/u_spec.rb b/spec/ruby/core/array/pack/u_spec.rb
index fe969cbb2d..b20093a647 100644
--- a/spec/ruby/core/array/pack/u_spec.rb
+++ b/spec/ruby/core/array/pack/u_spec.rb
@@ -18,6 +18,16 @@ describe "Array#pack with format 'u'" do
   it_behaves_like :array_pack_arguments, 'u'
   it_behaves_like :array_pack_taint, 'u'
 
+  it "calls #to_str to convert an Object to a String" do
+    obj = mock("pack u string")
+    obj.should_receive(:to_str).and_return("``abcdef")
+    [obj].pack("u*").should == "(8&!A8F-D968`\n"
+  end
+
+  it "will not implicitly convert a number to a string" do
+    -> { [0].pack('u') }.should raise_error(TypeError)
+  end
+
   it "encodes an empty string as an empty string" do
     [""].pack("u").should == ""
   end
diff --git a/spec/ruby/core/array/pack/w_spec.rb b/spec/ruby/core/array/pack/w_spec.rb
index 439fa02198..48ed4496a5 100644
--- a/spec/ruby/core/array/pack/w_spec.rb
+++ b/spec/ruby/core/array/pack/w_spec.rb
@@ -24,8 +24,20 @@ describe "Array#pack with format 'w'" do
     [obj].pack("w").should == "\x05"
   end
 
-  it "ignores NULL bytes between directives" do
-    [1, 2, 3].pack("w\x00w").should == "\x01\x02"
+  ruby_version_is ""..."3.3" do
+    it "ignores NULL bytes between directives" do
+      suppress_warning do
+        [1, 2, 3].pack("w\x00w").should == "\x01\x02"
+      end
+    end
+  end
+
+  ruby_version_is "3.3" do
+    it "raise ArgumentError for NULL bytes between directives" do
+      -> {
+        [1, 2, 3].pack("w\x00w")
+      }.should raise_error(ArgumentError, /unknown pack directive/)
+    end
   end
 
   it "ignores spaces between directives" do
diff --git a/spec/ruby/core/array/pack/x_spec.rb b/spec/ruby/core/array/pack/x_spec.rb
index a28dd0bf21..86c3ad1aa4 100644
--- a/spec/ruby/core/array/pack/x_spec.rb
+++ b/spec/ruby/core/array/pack/x_spec.rb
@@ -30,6 +30,7 @@ describe "Array#pack with format 'x'" do
 
   it "does not add a NULL byte when passed the '*' modifier" do
     [].pack("x*").should == ""
+    [1, 2].pack("Cx*C").should == "\x01\x02"
   end
 end
 
diff --git a/spec/ruby/core/array/pack/z_spec.rb b/spec/ruby/core/array/pack/z_spec.rb
index 82ce7b4a1c..5ad3afd69e 100644
--- a/spec/ruby/core/array/pack/z_spec.rb
+++ b/spec/ruby/core/array/pack/z_spec.rb
@@ -12,6 +12,16 @@ describe "Array#pack with format 'Z'" do
   it_behaves_like :array_pack_string, 'Z'
   it_behaves_like :array_pack_taint, 'Z'
 
+  it "calls #to_str to convert an Object to a String" do
+    obj = mock("pack Z string")
+    obj.should_receive(:to_str).and_return("``abcdef")
+    [obj].pack("Z*").should == "``abcdef\x00"
+  end
+
+  it "will not implicitly convert a number to a string" do
+    -> { [0].pack('Z') }.should raise_error(TypeError)
+  end
+
   it "adds all the bytes and appends a NULL byte when passed the '*' modifier" do
     ["abc"].pack("Z*").should == "abc\x00"
   end