[[FEAT]] Implement ES2019 RegExp "dotall"

Introduce a new warning to alert users of RegExp literals that include the new flag without using the "dot" atom.
jshint · Jan 29, 2019 · 457d732 · 457d732
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commit 457d732
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Showing 5 changed files with 90 additions and 12 deletions.
diff --git a/src/lex.js b/src/lex.js
@@ -1328,16 +1328,17 @@ Lexer.prototype = {
     var char = this.peek();
     var value = char;
     var body = "";
-    var flags = [];
     var groupReferences = [];
+    var allFlags = "";
+    var es5Flags = "";
     var malformed = false;
     var isCharSet = false;
     var isCharSetRange = false;
     var isGroup = false;
     var isQuantifiable = false;
     var hasInvalidQuantifier = false;
     var escapedChars = "";
-    var hasUFlag = function() { return flags.indexOf("u") > -1; };
+    var hasUFlag = function() { return allFlags.indexOf("u") > -1; };
     var escapeSequence;
     var groupCount = 0;
     var terminated, malformedDesc;
@@ -1648,7 +1649,7 @@ Lexer.prototype = {
 
     while (index < length) {
       char = this.peek(index);
-      if (!/[gimyu]/.test(char)) {
+      if (!/[gimyus]/.test(char)) {
         break;
       }
       if (char === "y") {
@@ -1706,18 +1707,38 @@ Lexer.prototype = {
         }
 
         body = translateUFlag(body);
+      } else if (char === "s") {
+        if (!state.inES9()) {
+          this.triggerAsync(
+            "warning",
+            {
+              code: "W119",
+              line: this.line,
+              character: this.char,
+              data: [ "DotAll RegExp flag", "9" ]
+            },
+            checks,
+            function() { return true; }
+          );
+        }
+        if (value.indexOf("s") > -1) {
+          malformedDesc = "Duplicate RegExp flag";
+        }
+      } else {
+        es5Flags += char;
       }
 
-      if (flags.indexOf(char) > -1) {
+      if (allFlags.indexOf(char) > -1) {
         malformedDesc = "Duplicate RegExp flag";
       }
-      flags.push(char);
+      allFlags += char;
 
       value += char;
+      allFlags += char;
       index += 1;
     }
 
-    if (flags.indexOf("u") === -1) {
+    if (allFlags.indexOf("u") === -1) {
       this.triggerAsync("warning", {
         code: "W147",
         line: this.line,
@@ -1728,7 +1749,7 @@ Lexer.prototype = {
     // Check regular expression for correctness.
 
     try {
-      new RegExp(body);
+      new RegExp(body, es5Flags);
     } catch (err) {
       /**
        * Because JSHint relies on the current engine's RegExp parser to
@@ -1746,6 +1767,12 @@ Lexer.prototype = {
         character: this.char,
         data: [ malformedDesc ]
       });
+    } else if (allFlags.indexOf("s") > -1 && !reg.regexpDot.test(body)) {
+      this.trigger("warning", {
+        code: "W148",
+        line: this.line,
+        character: this.char
+      });
     }
 
     return {

diff --git a/src/messages.js b/src/messages.js
@@ -239,7 +239,8 @@ var warnings = {
   W144: "'{a}' is a non-standard language feature. Enable it using the '{b}' unstable option.",
   W145: "Superfluous 'case' clause.",
   W146: "Unnecessary `await` expression.",
-  W147: "Regular expressions should include the 'u' flag."
+  W147: "Regular expressions should include the 'u' flag.",
+  W148: "Unnecessary RegExp 's' flag."
 };
 
 var info = {

diff --git a/src/reg.js b/src/reg.js
@@ -50,3 +50,6 @@ exports.regexpSyntaxChars = /[\^$\\.*+?()[\]{}|]/;
 exports.regexpQuantifiers = /[*+?{]/;
 
 exports.regexpCharClasses = /[dDsSwW]/;
+
+// Identifies the "dot" atom in regular expressions
+exports.regexpDot = /(^|[^\\])(\\\\)*\./;
diff --git a/tests/test262/expectations.txt b/tests/test262/expectations.txt
@@ -883,10 +883,6 @@ test/built-ins/RegExp/named-groups/unicode-references.js(default)
 test/built-ins/RegExp/named-groups/unicode-references.js(strict mode)
 test/built-ins/RegExp/named-groups/unicode-property-names.js(default)
 test/built-ins/RegExp/named-groups/unicode-property-names.js(strict mode)
-test/built-ins/RegExp/prototype/dotAll/this-val-regexp.js(default)
-test/built-ins/RegExp/prototype/dotAll/this-val-regexp.js(strict mode)
-test/built-ins/RegExp/prototype/flags/s.js(default)
-test/built-ins/RegExp/prototype/flags/s.js(strict mode)
 test/built-ins/RegExp/property-escapes/character-class.js(default)
 test/built-ins/RegExp/property-escapes/character-class.js(strict mode)
 test/built-ins/RegExp/property-escapes/grammar-extensions.js(default)

diff --git a/tests/unit/parser.js b/tests/unit/parser.js
@@ -787,6 +787,57 @@ exports.regexp.yFlag = function (test) {
   test.done();
 };
 
+exports.regexp.dotAll = function (test) {
+  TestRun(test, "flag presence - disallowed in editions prior to 2018")
+    .addError(1, 6, "'DotAll RegExp flag' is only available in ES9 (use 'esversion: 9').")
+    .addError(2, 6, "'DotAll RegExp flag' is only available in ES9 (use 'esversion: 9').")
+    .addError(3, 6, "'DotAll RegExp flag' is only available in ES9 (use 'esversion: 9').")
+    .test([
+      "void /./s;",
+      "void /./gs;",
+      "void /./sg;"
+    ], { esversion: 8 });
+
+  TestRun(test, "flag presence - allowed in 2018")
+    .test([
+      "void /./s;",
+      "void /./gs;",
+      "void /./sg;"
+    ], { esversion: 9 });
+
+  TestRun(test, "duplicate flag")
+    .addError(1, 6, "Invalid regular expression.")
+    .addError(2, 6, "Invalid regular expression.")
+    .test([
+      "void /./ss;",
+      "void /./sgs;"
+    ], { esversion: 9 });
+
+  TestRun(test, "missing dot")
+    .addError(1, 6, "Unnecessary RegExp 's' flag.")
+    .addError(2, 6, "Unnecessary RegExp 's' flag.")
+    .addError(3, 6, "Unnecessary RegExp 's' flag.")
+    .addError(4, 6, "Unnecessary RegExp 's' flag.")
+    .addError(5, 6, "Unnecessary RegExp 's' flag.")
+    .test([
+      "void /dotall flag without dot/s;",
+      "void /literal period \\./s;",
+      "void /\\. literal period/s;",
+      "void /literal period \\\\\\./s;",
+      "void /\\\\\\. literal period/s;"
+    ], { esversion: 9 });
+
+  TestRun(test, "dot following escape")
+    .test([
+      "void /RegExp dot \\\\./s;",
+      "void /\\\\. RegExp dot/s;",
+      "void /RegExp dot \\\\\\\\\./s;",
+      "void /\\\\\\\\\. RegExp dot/s;"
+    ], { esversion: 9 });
+
+  test.done();
+};
+
 exports.regexp.regressions = function (test) {
   // GH-536
   TestRun(test).test("str /= 5;", {es3: true}, { str: true });