Resolving bug 261278: strict mode implementation

js/rhino/docs/shell.html

@@ -40,6 +40,11 @@ or <tt>140</tt>. See <a href="overview.html#versions">JavaScript Language
 Versions</a> for more information on language versions.
 </blockquote>
 
+<tt>-strict</tt>
+<blockquote>
+Enable strict mode.
+</blockquote>
+
 <tt>-continuations</tt>
 <blockquote>
 Enable experiments support for continuations and set the optimization level to -1 to force interpretation mode.

js/rhino/src/org/mozilla/javascript/Context.java

@@ -233,9 +233,9 @@ public class Context
     public static final int FEATURE_DYNAMIC_SCOPE = 7;
 
     /**
-     * Control if highly experimental support for the continuation in the
+     * Control if experimental support for the continuations in the
      * interpreter is enabled.
-     * If Rhino embedding enables this highly experimental features, then
+     * If Rhino embedding enables this experimental features, then
      * <tt>Continuation</tt> object will be available to scripts.
      * When used with  pure interpretation mode (optimizatio level is -1)
      * <tt>Continuation</tt>it allows to capture and restore continuations.
@@ -248,6 +248,21 @@ public class Context
      */
     public static final int FEATURE_INTERPRETER_CONTINUATIONS = 8;
 
+    /**
+     * Control if strict mode is enabled.
+     * With strict mode enabled Rhino reports runtime errors in the following
+     * cases:
+     * <ul>
+     * <li> Assignment to non-existing names which typically indicates missed
+     *      <b>var</b> declaration.
+     * <li> Passing non-string arguments to the eval function.
+     * </ul>
+     * <p>
+     * By default {@link #hasFeature(int)} returns false.
+     * @since 1.6 Release 1
+     */
+    public static final int FEATURE_STRICT_MODE = 9;
+
     public static final String languageVersionProperty = "language version";
     public static final String errorReporterProperty   = "error reporter";
 
@@ -2106,6 +2121,7 @@ public class Context
      * @see #FEATURE_E4X
      * @see #FEATURE_DYNAMIC_SCOPE
      * @see #FEATURE_INTERPRETER_CONTINUATIONS
+     * @see #FEATURE_STRICT_MODE
      */
     public boolean hasFeature(int featureIndex)
     {

js/rhino/src/org/mozilla/javascript/ContextFactory.java

@@ -271,6 +271,9 @@ public class ContextFactory
 
           case Context.FEATURE_INTERPRETER_CONTINUATIONS:
             return false;
+
+          case Context.FEATURE_STRICT_MODE:
+            return false;
         }
         // It is a bug to call the method with unknown featureIndex
         throw new IllegalArgumentException(String.valueOf(featureIndex));

js/rhino/src/org/mozilla/javascript/ScriptRuntime.java

@@ -1777,20 +1777,16 @@ public class ScriptRuntime {
         } else {
             // "newname = 7;", where 'newname' has not yet
             // been defined, creates a new property in the
-            // global object. Find the global object by
+            // top scope unless strict mode is specified.
-            // walking up the scope chain.
+            if (cx.hasFeature(Context.FEATURE_STRICT_MODE)) {
+                throw Context.reportRuntimeError1("msg.assn.create.strict", id);
+            }
+            // Find the top scope by walking up the scope chain.
             bound = ScriptableObject.getTopLevelScope(scope);
             if (cx.useDynamicScope) {
                 bound = locateDynamicScope(cx, bound);
             }
             bound.put(id, bound, value);
-            /*
-            This code is causing immense performance problems in
-            scripts that assign to the variables as a way of creating them.
-            XXX need strict mode
-            String message = getMessage1("msg.assn.create", id);
-            Context.reportWarning(message);
-            */
         }
         return value;
     }
@@ -2213,6 +2209,9 @@ public class ScriptRuntime {
             return Undefined.instance;
         Object x = args[0];
         if (!(x instanceof String)) {
+            if (cx.hasFeature(Context.FEATURE_STRICT_MODE)) {
+                throw Context.reportRuntimeError0("msg.eval.nonstring.strict");
+            }
             String message = Context.getMessage0("msg.eval.nonstring");
             Context.reportWarning(message);
             return x;

js/rhino/src/org/mozilla/javascript/resources/Messages.properties

@@ -130,6 +130,10 @@ msg.eval.nonstring =\
     Calling eval() with anything other than a primitive string value will \
     simply return the value. Is this what you intended?
 
+msg.eval.nonstring.strict =\
+    Calling eval() with anything other than a primitive string value is not \
+    allowed in the strict mode.
+
 # NativeCall
 msg.only.from.new =\
     "{0}" may only be invoked from a "new" expression.
@@ -401,9 +405,9 @@ mag.too.deep.parser.recursion =\
     Too deep recursion while parsing
 
 # ScriptRuntime
-msg.assn.create =\
+msg.assn.create.strict =\
-    Assignment to undefined "{0}" will create a new variable. \
+    Attempt to assign non-existing name "{0}" in the strict mode. \
-    Add a variable statement at the top level scope to remove this warning.
+    It could indicate a missing variable statement.
 
 msg.prop.not.found =\
     Property {0} not found.
@@ -452,7 +456,7 @@ msg.no.ref.to.get =\
 
 msg.no.ref.to.set =\
     {0} is not a reference to set reference value tpo {1}.
-    
+
 msg.no.ref.from.function =\
     Function {0} can not be used as the left-hand side of assignment \
     or as an operand of ++ or -- operator.

js/rhino/toolsrc/org/mozilla/javascript/tools/shell/Main.java

@@ -192,6 +192,10 @@ public class Main
                 }
                 continue;
             }
+            if (arg.equals("-strict")) {
+                shellContextFactory.setStrictMode(true);
+                continue;
+            }
             if (arg.equals("-continuations")) {
                 shellContextFactory.setEnableContinuations(true);
                 cx.setOptimizationLevel(-1);

js/rhino/toolsrc/org/mozilla/javascript/tools/shell/ShellContextFactory.java

@@ -40,10 +40,14 @@ import org.mozilla.javascript.*;
 public class ShellContextFactory extends ContextFactory
 {
     private boolean enableContinuations;
+    private boolean strictMode;
 
     protected boolean hasFeature(Context cx, int featureIndex)
     {
-        if (featureIndex == Context.FEATURE_INTERPRETER_CONTINUATIONS) {
+        switch (featureIndex) {
+          case Context.FEATURE_STRICT_MODE:
+            return strictMode;
+          case Context.FEATURE_INTERPRETER_CONTINUATIONS:
             return enableContinuations;
         }
         return super.hasFeature(cx, featureIndex);
@@ -55,4 +59,10 @@ public class ShellContextFactory extends ContextFactory
         this.enableContinuations = flag;
     }
 
+    public void setStrictMode(boolean flag)
+    {
+        checkNotSealed();
+        this.strictMode = flag;
+    }
+
 }