[GR-59866] Improve validation of a Time.new single String argument

PullRequest: truffleruby/4416

spec/ruby/core/time/new_spec.rb

@@ -564,6 +564,12 @@ def obj.to_int; 3; end
             Time.new("2020-12-25")
           }.should raise_error(ArgumentError, /no time information|can't parse:/)
         end
+
+        it "raises ArgumentError if day is missing" do
+          -> {
+            Time.new("2020-12")
+          }.should raise_error(ArgumentError, /no time information|can't parse:/)
+        end
       end
 
       it "raises ArgumentError if subsecond is missing after dot" do
@@ -679,6 +685,26 @@ def obj.to_int; 3; end
           Time.new("2021-11-31 00:00:59 +09:00 abc")
         }.should raise_error(ArgumentError, /can't parse.+ abc/)
       end
+
+      ruby_version_is "3.2.3" do
+        it "raises ArgumentError when there are leading space characters" do
+          -> { Time.new(" 2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("\t2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("\n2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("\v2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("\f2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("\r2020-12-02 00:00:00") }.should raise_error(ArgumentError, /can't parse/)
+        end
+
+        it "raises ArgumentError when there are trailing whitespaces" do
+          -> { Time.new("2020-12-02 00:00:00 ") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("2020-12-02 00:00:00\t") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("2020-12-02 00:00:00\n") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("2020-12-02 00:00:00\v") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("2020-12-02 00:00:00\f") }.should raise_error(ArgumentError, /can't parse/)
+          -> { Time.new("2020-12-02 00:00:00\r") }.should raise_error(ArgumentError, /can't parse/)
+        end
+      end
     end
   end
 end

src/main/ruby/truffleruby/core/truffle/time_operations.rb

@@ -104,7 +104,7 @@ def self.new_from_string(time_class, str, **options)
                   : (?<min>  \d{2})
                   : (?<sec>  \d{2})
                   (?:\. (?<usec> \d+) )?
-              \s* (?<offset>\S+)?
+              (?:\s* (?<offset>\S+))?
              )?\z/x =~ str
         return self.compose(time_class, self.utc_offset_for_compose(offset || options[:in]), year, month, mday, hour, min, sec, usec)
       end