[GR-15990] Disable coverage in translator when multiple contexts are used

PullRequest: truffleruby/2027

Author: bjfish

src/main/java/org/truffleruby/RubyLanguage.java

@@ -134,6 +134,9 @@ public class RubyLanguage extends TruffleLanguage<RubyContext> {
 
     private final CyclicAssumption tracingCyclicAssumption = new CyclicAssumption("object-space-tracing");
     @CompilationFinal private volatile Assumption tracingAssumption = tracingCyclicAssumption.getAssumption();
+    public final Assumption singleContextAssumption = Truffle
+            .getRuntime()
+            .createAssumption("single RubyContext per RubyLanguage instance");
 
     public final CoreStrings coreStrings;
     public final CoreSymbols coreSymbols;
@@ -223,6 +226,7 @@ public void invalidateTracingAssumption() {
     protected void initializeMultipleContexts() {
         // TODO Make Symbol.all_symbols per context, by having a SymbolTable per context and creating new symbols with
         //  the per-language SymbolTable.
+        singleContextAssumption.invalidate();
     }
 
     @Override

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

@@ -3157,11 +3157,10 @@ private RubyNode addNewlineIfNeeded(ParseNode jrubyNode, RubyNode node) {
                 return node;
             }
 
-            if (context.getCoverageManager().isEnabled()) {
+            if (language.singleContextAssumption.isValid() && context.getCoverageManager().isEnabled()) {
                 node.unsafeSetIsCoverageLine();
                 context.getCoverageManager().setLineHasCode(source, current.toSourceSection(source).getStartLine());
             }
-
             node.unsafeSetIsNewLine();
         }