Fix MatchData#[index, length] when index is larger than number of matched values

PullRequest: truffleruby/4290

Author: andrykonchin

CHANGELOG.md

@@ -15,6 +15,7 @@ Bug fixes:
 * Fix `IO#{read_nonblock,readpartial,sysread}`, `BasicSocket#{recv,recv_nonblock}`, `{Socket,UDPSocket}#recvfrom_nonblock`, `UnixSocket#recvfrom` and preserve a provided buffer's encoding (#3506, @andrykonchyn).
 * Repair `IO#{wait_readable,wait_writable,wait}` to be interruptible (#3504, @andrykonchin).
 * Fix Hash value omission for constant names (@andrykonchin).
+* Fix `MatchData#[index, length]` when index is larger than number of matched values (@andrykonchin).
 
 Compatibility:
 

spec/ruby/core/matchdata/element_reference_spec.rb

@@ -20,6 +20,11 @@
     # negative index is larger than the number of match values
     /(.)(.)(\d+)(\d)/.match("THX1138.")[-30, 2].should == nil
 
+    # positive index larger than number of match values
+    /(.)(.)(\d+)(\d)/.match("THX1138.")[5, 2].should == []
+    /(.)(.)(\d+)(\d)/.match("THX1138.")[6, 2].should == nil
+    /(.)(.)(\d+)(\d)/.match("THX1138.")[30, 2].should == nil
+
     # length argument larger than number of match values is capped to match value length
     /(.)(.)(\d+)(\d)/.match("THX1138.")[3, 10].should == %w|113 8|
 

src/main/java/org/truffleruby/core/regexp/MatchDataNodes.java

@@ -279,6 +279,7 @@ Object getIndex(RubyMatchData matchData, int index, int length,
                 @Cached @Exclusive InlinedConditionProfile negativeLengthProfile,
                 @Cached @Shared InlinedConditionProfile normalizedIndexProfile,
                 @Cached @Exclusive InlinedConditionProfile negativeIndexProfile,
+                @Cached @Exclusive InlinedConditionProfile tooLargeIndexProfile,
                 @Cached @Exclusive InlinedConditionProfile tooLargeTotalProfile) {
             final Object[] values = getValuesNode.execute(matchData);
 
@@ -294,6 +295,10 @@ Object getIndex(RubyMatchData matchData, int index, int length,
                 }
             }
 
+            if (tooLargeIndexProfile.profile(this, index > values.length)) {
+                return nil;
+            }
+
             int endIndex = index + length;
             if (tooLargeTotalProfile.profile(this, endIndex > values.length)) {
                 endIndex = values.length;

test/mri/excludes/TestRegexp.rb

@@ -19,7 +19,6 @@
 exclude :test_cache_optimization_exponential, "NoMethodError: undefined method `timeout=' for Regexp:Class"
 exclude :test_cache_optimization_square, "NoMethodError: undefined method `timeout=' for Regexp:Class"
 exclude :test_invalid_free_at_parse_depth_limit_over, "NameError: uninitialized constant Bug"
-exclude :test_match_aref, "throws internal exception"
 exclude :test_match_without_regexp, "Encoding::CompatibilityError: incompatible encoding regexp match (Shift_JIS regexp with UTF-8 string)"
 exclude :test_parse, "Polyglot::ForeignException: invalid group reference 80"
 exclude :test_parse_kg, "Polyglot::ForeignException: undefined name <-1> reference"