[[FIX]] Do not fail on valid configurations

When interpreting configuration values for strict-mode-related options,
do not modify user-specified values. Instead, preserve the values as
specified and encapsulate interpretation logic into stateless helper
methods on the `state` object.

This pattern allows JSHint to consistently issue warnings about invalid
configurations by ensuring that at any given time, all option values in
the `state` object reflect values explicitly specified by the user.

As noted in the in-line documentation, this approach required making
explicit certain sub-optimal behaviors which were previously implicit.
These concerns would best be addressed in a later patch, distinct from
the regression that prompted this changeset.

src/jshint.js

@@ -215,9 +215,6 @@ var JSHINT = (function() {
     }
 
     if (state.option.module) {
-      if (state.option.strict === true) {
-        state.option.strict = "global";
-      }
       /**
        * TODO: Extend this restriction to *all* ES6-specific options.
        */
@@ -302,10 +299,6 @@ var JSHINT = (function() {
       combine(predefined, vars.wsh);
     }
 
-    if (state.option.globalstrict && state.option.strict !== false) {
-      state.option.strict = "global";
-    }
-
     if (state.option.yui) {
       combine(predefined, vars.yui);
     }
@@ -1647,8 +1640,7 @@ var JSHINT = (function() {
     if (r && !(r.identifier && r.value === "function") &&
         !(r.type === "(punctuator)" && r.left &&
           r.left.identifier && r.left.value === "function")) {
-      if (!state.isStrict() &&
-          state.option.strict === "global") {
+      if (!state.isStrict() && state.stmtMissingStrict()) {
         warning("E007");
       }
     }
@@ -5296,10 +5288,7 @@ var JSHINT = (function() {
         directives();
 
         if (state.directive["use strict"]) {
-          if (state.option.strict !== "global" &&
-              !((state.option.strict === true || !state.option.strict) &&
-                (state.option.globalstrict || state.option.module || state.option.node ||
-                 state.option.phantom || state.option.browserify))) {
+          if (!state.allowsGlobalUsd()) {
             warning("W097", state.tokens.prev);
           }
         }

src/state.js

@@ -14,6 +14,42 @@ var state = {
       this.option.module || this.option.strict === "implied";
   },
 
+  /**
+   * Determine if the current state warrants a warning for statements outside
+   * of strict mode code.
+   *
+   * While emitting warnings based on function scope would be more intuitive
+   * (and less noisy), JSHint observes statement-based semantics in order to
+   * preserve legacy behavior.
+   *
+   * This method does not take the state of the parser into account, making no
+   * distinction between global code and function code. Because the "missing
+   * 'use strict'" warning is *also* reported at function boundaries, this
+   * function interprets `strict` option values `true` and `undefined` as
+   * equivalent.
+   */
+  stmtMissingStrict: function() {
+    if (this.option.strict === "global") {
+      return true;
+    }
+
+    if (this.option.strict === false) {
+      return false;
+    }
+
+    if (this.option.globalstrict) {
+      return true;
+    }
+
+    return false;
+  },
+
+  allowsGlobalUsd: function() {
+    return this.option.strict === "global" || this.option.globalstrict ||
+      this.option.module || this.option.node || this.option.phantom ||
+      this.option.browserify;
+  },
+
   // Assumption: chronologically ES3 < ES5 < ES6 < Moz
 
   inMoz: function() {

tests/unit/options.js

@@ -1905,6 +1905,22 @@ exports.globalstrict = function (test) {
   TestRun(test, "gh-2661")
     .test("'use strict';", { strict: false, globalstrict: true });
 
+  TestRun(test, "gh-2836 (1)")
+    .test([
+      "// jshint globalstrict: true",
+      // The specific option set by the following directive is not relevant.
+      // Any option set by another directive will trigger the regression.
+      "// jshint undef: true"
+    ]);
+
+  TestRun(test, "gh-2836 (2)")
+    .test([
+      "// jshint strict: true, globalstrict: true",
+      // The specific option set by the following directive is not relevant.
+      // Any option set by another directive will trigger the regression.
+      "// jshint undef: true"
+    ]);
+
   test.done();
 };