[GR-18163] Update String#lstrip! to remove leading null characters

PullRequest: truffleruby/3217

Author: bjfish

CHANGELOG.md

@@ -38,6 +38,7 @@ Compatibility:
 * Update `String#rindex` to only accept `Regexp` or objects convertable to `String` as the first parameter (#2608, @bjfish).
 * Update `String#<<` to require one argument (#2609, @bjfish).
 * Update `String#split` to raise `TypeError` when false is given (#2606, @bjfish).
+* Update `String#lstrip!` to remove leading null characters (#2607, @bjfish).
 
 Performance:
 

spec/ruby/core/string/lstrip_spec.rb

@@ -12,7 +12,7 @@
    "hello".lstrip.should == "hello"
   end
 
-  ruby_version_is '3.1' do
+  ruby_version_is '3.0' do
     it "strips leading \\0" do
      "\x00hello".lstrip.should == "hello"
      "\000 \000hello\000 \000".lstrip.should == "hello\000 \000"
@@ -35,7 +35,7 @@
     a.should == "hello  "
   end
 
-  ruby_version_is '3.1' do
+  ruby_version_is '3.0' do
     it "strips leading \\0" do
       a = "\000 \000hello\000 \000"
       a.lstrip!

spec/ruby/core/string/strip_spec.rb

@@ -11,7 +11,7 @@
     "\tgoodbye\r\v\n".strip.should == "goodbye"
   end
 
-  ruby_version_is '3.1' do
+  ruby_version_is '3.0' do
     it "returns a copy of self without leading and trailing NULL bytes and whitespace" do
       " \x00 goodbye \x00 ".strip.should == "goodbye"
     end
@@ -43,7 +43,7 @@
     a.should == "hello"
   end
 
-  ruby_version_is '3.1' do
+  ruby_version_is '3.0' do
     it "removes leading and trailing NULL bytes and whitespace" do
       a = "\000 goodbye \000"
       a.strip!

src/main/java/org/truffleruby/core/string/StringNodes.java

@@ -1804,15 +1804,15 @@ protected Object lstripBangSingleByte(RubyString string,
             // Check the first code point to see if it's a space. In the case of strings without leading spaces,
             // this check can avoid having to materialize the entire byte[] (a potentially expensive operation
             // for ropes) and can avoid having to compile the while loop.
-            if (noopProfile.profile(!StringSupport.isAsciiSpace(firstCodePoint))) {
+            if (noopProfile.profile(!isSpace(firstCodePoint))) {
                 return nil;
             }
 
             final int end = rope.byteLength();
             final byte[] bytes = bytesNode.execute(rope);
 
             int p = 0;
-            while (p < end && StringSupport.isAsciiSpace(bytes[p])) {
+            while (p < end && isSpace(bytes[p])) {
                 p++;
             }
 
@@ -1838,7 +1838,7 @@ protected Object lstripBang(RubyString string,
             int p = s;
             while (p < end) {
                 int c = getCodePointNode.executeGetCodePoint(enc, rope, p);
-                if (!ASCIIEncoding.INSTANCE.isSpace(c)) {
+                if (!(c == 0 || ASCIIEncoding.INSTANCE.isSpace(c))) {
                     break;
                 }
                 p += StringSupport.codeLength(enc.jcoding, c);
@@ -1852,6 +1852,10 @@ protected Object lstripBang(RubyString string,
 
             return nil;
         }
+
+        private boolean isSpace(int c) {
+            return c == 0 || StringSupport.isAsciiSpace(c);
+        }
     }
 
     @CoreMethod(names = "ord")