Implement nullish assignment operator ??=

mozilla · Oct 18, 2024 · 005371f · 005371f
1 parent 5c8c512
commit 005371f
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Showing 7 changed files with 41 additions and 14 deletions.
diff --git a/rhino/src/main/java/org/mozilla/javascript/IRFactory.java b/rhino/src/main/java/org/mozilla/javascript/IRFactory.java
@@ -2150,6 +2150,9 @@ private Node createAssignment(int assignType, Node left, Node right) {
             case Token.ASSIGN_EXP:
                 assignOp = Token.EXP;
                 break;
+            case Token.ASSIGN_NULLISH:
+                assignOp = Token.NULLISH_COALESCING;
+                break;
             default:
                 throw Kit.codeBug();
         }

diff --git a/rhino/src/main/java/org/mozilla/javascript/Node.java b/rhino/src/main/java/org/mozilla/javascript/Node.java
@@ -943,6 +943,8 @@ public boolean hasSideEffects() {
             case Token.ASSIGN_LSH:
             case Token.ASSIGN_RSH:
             case Token.ASSIGN_URSH:
+            case Token.ASSIGN_EXP:
+            case Token.ASSIGN_NULLISH:
             case Token.ENTERWITH:
             case Token.LEAVEWITH:
             case Token.RETURN:

diff --git a/rhino/src/main/java/org/mozilla/javascript/Token.java b/rhino/src/main/java/org/mozilla/javascript/Token.java
@@ -148,9 +148,10 @@ public static enum CommentType {
             ASSIGN_MUL = ASSIGN_SUB + 1, // *=
             ASSIGN_DIV = ASSIGN_MUL + 1, // /=
             ASSIGN_MOD = ASSIGN_DIV + 1, // %=
-            ASSIGN_EXP = ASSIGN_MOD + 1; // **=
+            ASSIGN_EXP = ASSIGN_MOD + 1, // **=
+            ASSIGN_NULLISH = ASSIGN_EXP + 1; // ??=
     public static final int FIRST_ASSIGN = ASSIGN,
-            LAST_ASSIGN = ASSIGN_EXP,
+            LAST_ASSIGN = ASSIGN_NULLISH,
             HOOK = LAST_ASSIGN + 1, // conditional (?:)
             COLON = HOOK + 1,
             OR = COLON + 1, // logical or (||)
@@ -468,6 +469,8 @@ public static String typeToName(int token) {
                 return "ASSIGN_MOD";
             case ASSIGN_EXP:
                 return "ASSIGN_EXP";
+            case ASSIGN_NULLISH:
+                return "ASSIGN_NULLISH";
             case HOOK:
                 return "HOOK";
             case COLON:

diff --git a/rhino/src/main/java/org/mozilla/javascript/TokenStream.java b/rhino/src/main/java/org/mozilla/javascript/TokenStream.java
@@ -1156,6 +1156,9 @@ && peekChar() == '!'
                             }
                             ungetChar('.');
                         } else if (matchChar('?')) {
+                            if (matchChar('=')) {
+                                return Token.ASSIGN_NULLISH;
+                            }
                             return Token.NULLISH_COALESCING;
                         }
                     }

diff --git a/rhino/src/main/java/org/mozilla/javascript/ast/AstNode.java b/rhino/src/main/java/org/mozilla/javascript/ast/AstNode.java
@@ -126,6 +126,7 @@ public abstract class AstNode extends Node implements Comparable<AstNode> {
         operatorNames.put(Token.ASSIGN_MOD, "%=");
         operatorNames.put(Token.ASSIGN_BITXOR, "^=");
         operatorNames.put(Token.ASSIGN_EXP, "**=");
+        operatorNames.put(Token.ASSIGN_NULLISH, "??=");
         operatorNames.put(Token.VOID, "void");
 
         StringBuilder sb = new StringBuilder();
@@ -374,6 +375,8 @@ public boolean hasSideEffects() {
             case Token.ASSIGN_RSH:
             case Token.ASSIGN_SUB:
             case Token.ASSIGN_URSH:
+            case Token.ASSIGN_EXP:
+            case Token.ASSIGN_NULLISH:
             case Token.BLOCK:
             case Token.BREAK:
             case Token.CALL:

diff --git a/tests/src/test/java/org/mozilla/javascript/tests/NullishCoalescingOpTest.java b/tests/src/test/java/org/mozilla/javascript/tests/NullishCoalescingOpTest.java
@@ -72,4 +72,25 @@ public void testNullishCoalescingDoesNotLeakVariables() {
         String script = "$0 = false; true ?? true; $0";
         Utils.assertWithAllOptimizationLevelsES6(false, script);
     }
+
+    @Test
+    public void testNullishAssignmentRequiresES6() {
+        Utils.runWithAllOptimizationLevels(
+                cx -> {
+                    Scriptable scope = cx.initStandardObjects();
+                    assertThrows(
+                            EvaluatorException.class,
+                            () ->
+                                    cx.evaluateString(
+                                            scope, "a = true; a ??= false", "test.js", 0, null));
+                    return null;
+                });
+    }
+
+    @Test
+    public void testNullishAssignment() {
+        Utils.assertWithAllOptimizationLevelsES6(true, "a = true; a ??= false; a");
+        Utils.assertWithAllOptimizationLevelsES6(false, "a = undefined; a ??= false; a");
+        Utils.assertWithAllOptimizationLevelsES6(false, "a = null; a ??= false; a");
+    }
 }
diff --git a/tests/testsrc/test262.properties b/tests/testsrc/test262.properties
@@ -4942,7 +4942,7 @@ language/expressions/less-than-or-equal 0/47 (0.0%)
 language/expressions/logical-and 1/18 (5.56%)
     tco-right.js {unsupported: [tail-call-optimization]}
 
-language/expressions/logical-assignment 53/78 (67.95%)
+language/expressions/logical-assignment 46/78 (58.97%)
     left-hand-side-private-reference-accessor-property-and.js {unsupported: [class-fields-private]}
     left-hand-side-private-reference-accessor-property-nullish.js {unsupported: [class-fields-private]}
     left-hand-side-private-reference-accessor-property-or.js {unsupported: [class-fields-private]}
@@ -4973,21 +4973,14 @@ language/expressions/logical-assignment 53/78 (67.95%)
     lgcl-and-assignment-operator-non-extensible.js strict
     lgcl-and-assignment-operator-non-simple-lhs.js
     lgcl-and-assignment-operator-non-writeable.js strict
-    lgcl-nullish-assignment-operator.js
-    lgcl-nullish-assignment-operator-bigint.js
+    lgcl-nullish-arguments-strict.js strict
     lgcl-nullish-assignment-operator-lhs-before-rhs.js
     lgcl-nullish-assignment-operator-namedevaluation-arrow-function.js
     lgcl-nullish-assignment-operator-namedevaluation-class-expression.js
     lgcl-nullish-assignment-operator-namedevaluation-function.js
-    lgcl-nullish-assignment-operator-no-set.js strict
     lgcl-nullish-assignment-operator-no-set-put.js strict
-    lgcl-nullish-assignment-operator-non-extensible.js strict
+    lgcl-nullish-assignment-operator-non-simple-lhs.js
     lgcl-nullish-assignment-operator-non-writeable.js strict
-    lgcl-nullish-assignment-operator-non-writeable-put.js strict
-    lgcl-nullish-assignment-operator-unresolved-lhs.js strict
-    lgcl-nullish-assignment-operator-unresolved-rhs.js
-    lgcl-nullish-assignment-operator-unresolved-rhs-put.js
-    lgcl-nullish-whitespace.js
     lgcl-or-arguments-strict.js strict
     lgcl-or-assignment-operator-lhs-before-rhs.js
     lgcl-or-assignment-operator-namedevaluation-arrow-function.js
@@ -5053,7 +5046,7 @@ language/expressions/new 41/59 (69.49%)
 
 ~language/expressions/new.target
 
-language/expressions/object 809/1169 (69.2%)
+language/expressions/object 808/1169 (69.12%)
     dstr/async-gen-meth-ary-init-iter-close.js {unsupported: [async-iteration, async]}
     dstr/async-gen-meth-ary-init-iter-get-err.js {unsupported: [async-iteration]}
     dstr/async-gen-meth-ary-init-iter-get-err-array-prototype.js {unsupported: [async-iteration]}
@@ -5806,7 +5799,6 @@ language/expressions/object 809/1169 (69.2%)
     accessor-name-literal-numeric-octal.js {strict: [-1], non-strict: [-1]}
     computed-__proto__.js
     concise-generator.js
-    cpn-obj-lit-computed-property-name-from-assignment-expression-coalesce.js
     cpn-obj-lit-computed-property-name-from-async-arrow-function-expression.js
     cpn-obj-lit-computed-property-name-from-await-expression.js {unsupported: [module, async]}
     cpn-obj-lit-computed-property-name-from-yield-expression.js