[Compatibility] Add alias String#dedup to String#-@ for Ruby v3.2

[itarato]

Source: #3039

String#dedup has been added as an alias to String#-@. [Feature #18595]

[andrykonchin]

suggestion: String#-@ is handled in a special way at parsing time. It's inlined when is called on a String literal to avoid method call. It makes sense to treat the #dedup method in the same way.

Inlining is implemented here:

truffleruby/src/main/java/org/truffleruby/parser/BodyTranslator.java

Lines 493 to 501 in 2beb695

	if (receiver instanceof StrParseNode &&
	(methodName.equals("freeze") || methodName.equals("-@"))) {
	final StrParseNode strNode = (StrParseNode) receiver;
	final TruffleString tstring = strNode.getValue();
	final ImmutableRubyString frozenString = language.getFrozenStringLiteral(tstring, strNode.encoding);
	return addNewlineIfNeeded(node, withSourceSection(
	sourceSection,
	new FrozenStringLiteralNode(frozenString, FrozenStrings.METHOD)));
	}

[itarato]

suggestion: String#-@ is handled in a special way at parsing time. It's inlined when is called on a String literal to avoid method call. It makes sense to treat the #dedup method in the same way.

Inlining is implemented here:

truffleruby/src/main/java/org/truffleruby/parser/BodyTranslator.java

Lines 493 to 501 in 2beb695

	if (receiver instanceof StrParseNode &&
	(methodName.equals("freeze") || methodName.equals("-@"))) {
	final StrParseNode strNode = (StrParseNode) receiver;
	final TruffleString tstring = strNode.getValue();
	final ImmutableRubyString frozenString = language.getFrozenStringLiteral(tstring, strNode.encoding);
	return addNewlineIfNeeded(node, withSourceSection(
	sourceSection,
	new FrozenStringLiteralNode(frozenString, FrozenStrings.METHOD)));
	}

Thanks for pointing this out. Added dedup there.

[andrykonchin]

Thank you!

[andrykonchin]

After inlining one test case fails:

1)
String#dedup interns the provided string if it is frozen FAILED
Expected "this string is unique and frozen 0.452[28](https://github.com/oracle/truffleruby/actions/runs/5014365700/jobs/8988815849?pr=3042#step:8:29)764636217345"
to be identical to "this string is unique and frozen 0.45228764636217345"
/home/runner/work/truffleruby/truffleruby/spec/ruby/core/string/shared/dedup.rb:54:in `block (3 levels) in <top (required)>'
/home/runner/work/truffleruby/truffleruby/spec/ruby/core/string/dedup_spec.rb:4:in `<top (required)>'

Right now it fails for String#-@ as well and is excluded (here spec/tags/core/string/uminus_tags.txt). Probably we should exclude it for dedup as well. You can use a command jt tag <path-to-spec-file> locally to create a similar tag-file for the String#dedup method.

[itarato]

After inlining one test case fails:

1)
String#dedup interns the provided string if it is frozen FAILED
Expected "this string is unique and frozen 0.452[28](https://github.com/oracle/truffleruby/actions/runs/5014365700/jobs/8988815849?pr=3042#step:8:29)764636217345"
to be identical to "this string is unique and frozen 0.45228764636217345"
/home/runner/work/truffleruby/truffleruby/spec/ruby/core/string/shared/dedup.rb:54:in `block (3 levels) in <top (required)>'
/home/runner/work/truffleruby/truffleruby/spec/ruby/core/string/dedup_spec.rb:4:in `<top (required)>'

Right now it fails for String#-@ as well and is excluded (here spec/tags/core/string/uminus_tags.txt). Probably we should exclude it for dedup as well. You can use a command jt tag <path-to-spec-file> locally to create a similar tag-file for the String#dedup method.

Thank you, just did that.

[andrykonchin]

Thank you!

[eregon]

FYI we shouldn't modify these files, they should reflect the MRI version we import.
But it's no big deal, let's leave as-is for this PR, it will overridden on 3.2 import.

[itarato]

What is the right way to do this? Without this tests will complain that the method is not exposed?

[eregon]

See https://github.com/oracle/truffleruby/blob/master/spec/truffle/methods_spec.rb, so you'd just use jt tag to mark as extra method, until the 3.2 import which would then regenerate those files.

[itarato]

Noted, thanks!