Bug 1317397: Only set lastIndex for global or sticky RegExps in RegExpBuiltinExec per ES2017

1 files changed, 122 insertions, 0 deletions

diff --git a/js/src/tests/ecma_2017/lastIndex-match-or-replace.js b/js/src/tests/ecma_2017/lastIndex-match-or-replace.js
new file mode 100644
index 000000000..b0a8b537c
--- /dev/null
+++ b/js/src/tests/ecma_2017/lastIndex-match-or-replace.js
@@ -0,0 +1,122 @@
+// RegExp.prototype[Symbol.match, Symbol.replace]: Test lastIndex changes for ES2017.
+
+// RegExp-like class to test the RegExp method slow paths.
+class DuckRegExp extends RegExp {
+    constructor(pattern, flags) {
+        return Object.create(DuckRegExp.prototype, {
+            regExp: {
+                value: new RegExp(pattern, flags)
+            },
+            lastIndex: {
+                value: 0, writable: true, enumerable: false, configurable: false
+            }
+        });
+    }
+
+    exec(...args) {
+        this.regExp.lastIndex = this.lastIndex;
+        try {
+            return this.regExp.exec(...args);
+        } finally {
+            if (this.global || this.sticky)
+                this.lastIndex = this.regExp.lastIndex;
+        }
+    }
+
+    get source() { return this.regExp.source; }
+
+    get global() { return this.regExp.global; }
+    get ignoreCase() { return this.regExp.ignoreCase; }
+    get multiline() { return this.regExp.multiline; }
+    get sticky() { return this.regExp.sticky; }
+    get unicode() { return this.regExp.unicode; }
+}
+
+// Test various combinations of:
+// - Pattern matches or doesn't match
+// - Global and/or sticky flag is set.
+// - lastIndex exceeds the input string length
+// - lastIndex is +-0
+const testCases = [
+    { regExp: /a/,  lastIndex: 0, input: "a", result: 0 },
+    { regExp: /a/g, lastIndex: 0, input: "a", result: 0 },
+    { regExp: /a/y, lastIndex: 0, input: "a", result: 1 },
+
+    { regExp: /a/,  lastIndex: 0, input: "b", result: 0 },
+    { regExp: /a/g, lastIndex: 0, input: "b", result: 0 },
+    { regExp: /a/y, lastIndex: 0, input: "b", result: 0 },
+
+    { regExp: /a/,  lastIndex: -0, input: "a", result: -0 },
+    { regExp: /a/g, lastIndex: -0, input: "a", result: 0 },
+    { regExp: /a/y, lastIndex: -0, input: "a", result: 1 },
+
+    { regExp: /a/,  lastIndex: -0, input: "b", result: -0 },
+    { regExp: /a/g, lastIndex: -0, input: "b", result: 0 },
+    { regExp: /a/y, lastIndex: -0, input: "b", result: 0 },
+
+    { regExp: /a/,  lastIndex: -1, input: "a", result: -1 },
+    { regExp: /a/g, lastIndex: -1, input: "a", result: 0 },
+    { regExp: /a/y, lastIndex: -1, input: "a", result: 1 },
+
+    { regExp: /a/,  lastIndex: -1, input: "b", result: -1 },
+    { regExp: /a/g, lastIndex: -1, input: "b", result: 0 },
+    { regExp: /a/y, lastIndex: -1, input: "b", result: 0 },
+
+    { regExp: /a/,  lastIndex: 100, input: "a", result: 100 },
+    { regExp: /a/g, lastIndex: 100, input: "a", result: 0 },
+    { regExp: /a/y, lastIndex: 100, input: "a", result: 0 },
+];
+
+for (let method of [RegExp.prototype[Symbol.match], RegExp.prototype[Symbol.replace]]) {
+    for (let Constructor of [RegExp, DuckRegExp]) {
+        // Basic test.
+        for (let {regExp, lastIndex, input, result} of testCases) {
+            let re = new Constructor(regExp);
+            re.lastIndex = lastIndex;
+            Reflect.apply(method, re, [input]);
+            assertEq(re.lastIndex, result);
+        }
+
+        // Test when lastIndex is non-writable.
+        for (let {regExp, lastIndex, input} of testCases) {
+            let re = new Constructor(regExp);
+            Object.defineProperty(re, "lastIndex", { value: lastIndex, writable: false });
+            if (re.global || re.sticky) {
+                assertThrowsInstanceOf(() => Reflect.apply(method, re, [input]), TypeError);
+            } else {
+                Reflect.apply(method, re, [input]);
+            }
+            assertEq(re.lastIndex, lastIndex);
+        }
+
+        // Test when lastIndex is changed to non-writable as a side-effect.
+        for (let {regExp, lastIndex, input, result} of testCases) {
+            let re = new Constructor(regExp);
+            let called = false;
+            re.lastIndex = {
+                valueOf() {
+                    assertEq(called, false);
+                    called = true;
+                    Object.defineProperty(re, "lastIndex", { value: 9000, writable: false });
+                    return lastIndex;
+                }
+            };
+            if (re.sticky) {
+                assertThrowsInstanceOf(() => Reflect.apply(method, re, [input]), TypeError);
+                assertEq(called, true);
+                assertEq(re.lastIndex, 9000);
+            } else if (re.global) {
+                Reflect.apply(method, re, [input]);
+                assertEq(called, false);
+                assertEq(re.lastIndex, result);
+            } else {
+                Reflect.apply(method, re, [input]);
+                assertEq(called, true);
+                assertEq(re.lastIndex, 9000);
+            }
+        }
+    }
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);