Can't make an enum set out of empty collection

headius · headius · commit 3f21dfd19188 · 2026-02-03T12:58:18.000-06:00
diff --git a/src/main/java/org/jruby/prism/parser/ParserPrismBase.java b/src/main/java/org/jruby/prism/parser/ParserPrismBase.java
@@ -231,7 +231,7 @@ private EnumSet<ParsingOptions.CommandLine> commandLineFromConfig(RubyInstanceCo
         if (config.isAssumePrinting()) list.add(ParsingOptions.CommandLine.P); // -p
         if (config.isXFlag()) list.add(ParsingOptions.CommandLine.X);          // -x
 
-        return EnumSet.copyOf(list);
+        return list.isEmpty() ? EnumSet.noneOf(ParsingOptions.CommandLine.class) : EnumSet.copyOf(list);
     }
 
     private void writeUnsignedInt(ByteList buf, int index, int value) {

Original file line number	Diff line number	Diff line change
`@@ -231,7 +231,7 @@ private EnumSet<ParsingOptions.CommandLine> commandLineFromConfig(RubyInstanceCo`
`231`	`231`	`if (config.isAssumePrinting()) list.add(ParsingOptions.CommandLine.P); // -p`
`232`	`232`	`if (config.isXFlag()) list.add(ParsingOptions.CommandLine.X); // -x`
`233`	`233`
`234`		`- return EnumSet.copyOf(list);`
	`234`	`+ return list.isEmpty() ? EnumSet.noneOf(ParsingOptions.CommandLine.class) : EnumSet.copyOf(list);`
`235`	`235`	`}`
`236`	`236`
`237`	`237`	`private void writeUnsignedInt(ByteList buf, int index, int value) {`