Retype these cache fields to provide better type information.

I do not know if a JVM can do this, but knowing that the fields on ThreadContext are final, and you're always accessing e.g. context.tru, and context.tru is always truthy, there may be cases that can fold away. Maybe. In any case, this found a bug in RubyGlobal where an object that could never be nil was being compared to nil.
jruby · Mar 1, 2018 · 75ac955 · 75ac955
1 parent 9b50958
commit 75ac955
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Showing 2 changed files with 10 additions and 13 deletions.
diff --git a/core/src/main/java/org/jruby/RubyGlobal.java b/core/src/main/java/org/jruby/RubyGlobal.java
@@ -511,13 +511,9 @@ private IRubyObject case_aware_op_aset(ThreadContext context, IRubyObject key, f
             if (updateRealENV) {
                 final POSIX posix = context.runtime.getPosix();
                 final String keyAsJava = keyAsStr.asJavaString();
-                // libc (un)setenv is not reentrant, so we need to synchronize across the entire JVM (JRUBY-5933)
-                if (valueAsStr == context.nil) {
-                    synchronized (Object.class) { posix.unsetenv(keyAsJava); }
-                } else {
-                    final String valueAsJava = valueAsStr.asJavaString();
-                    synchronized (Object.class) { posix.setenv(keyAsJava, valueAsJava, 1); }
-                }
+                final String valueAsJava = valueAsStr.asJavaString();
+                // libc setenv is not reentrant, so we need to synchronize across the entire JVM (JRUBY-5933)
+                synchronized (ProcessBuilder.class) { posix.setenv(keyAsJava, valueAsJava, 1); }
             }
 
             return super.op_aset(context, keyAsStr, valueAsStr);

diff --git a/core/src/main/java/org/jruby/runtime/ThreadContext.java b/core/src/main/java/org/jruby/runtime/ThreadContext.java
@@ -43,6 +43,7 @@
 import org.jruby.RubyContinuation.Continuation;
 import org.jruby.RubyInstanceConfig;
 import org.jruby.RubyModule;
+import org.jruby.RubyNil;
 import org.jruby.RubyRegexp;
 import org.jruby.RubyString;
 import org.jruby.RubyThread;
@@ -92,9 +93,9 @@ public static ThreadContext newContext(Ruby runtime) {
 
     // runtime, nil, and runtimeCache cached here for speed of access from any thread
     public final Ruby runtime;
-    public final IRubyObject nil;
-    public final RubyBoolean tru;
-    public final RubyBoolean fals;
+    public final RubyNil nil;
+    public final RubyBoolean.True tru;
+    public final RubyBoolean.False fals;
     public final RuntimeCache runtimeCache;
 
     // Is this thread currently with in a function trace?
@@ -194,9 +195,9 @@ public SecureRandom getSecureRandom() {
      */
     private ThreadContext(Ruby runtime) {
         this.runtime = runtime;
-        this.nil = runtime.getNil();
-        this.tru = runtime.getTrue();
-        this.fals = runtime.getFalse();
+        this.nil = (RubyNil) runtime.getNil();
+        this.tru = (RubyBoolean.True) runtime.getTrue();
+        this.fals = (RubyBoolean.False) runtime.getFalse();
         this.currentBlockType = Block.Type.NORMAL;
         this.savedExcInLambda = null;