[[FIX]] It is not un-necessary to assign undefined in a loop

Fixes #1191
jshint · Aug 8, 2015 · e8ce9bf · e8ce9bf
1 parent 1bbcc64
commit e8ce9bf
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Showing 3 changed files with 43 additions and 4 deletions.
diff --git a/src/jshint.js b/src/jshint.js
@@ -3555,7 +3555,8 @@ var JSHINT = (function() {
         state.nameStack.set(state.tokens.curr);
 
         advance("=");
-        if (!prefix && report && state.tokens.next.id === "undefined") {
+        if (!prefix && report && !state.funct["(loopage)"] &&
+          state.tokens.next.id === "undefined") {
           warning("W080", state.tokens.prev, state.tokens.prev.value);
         }
         if (peek(0).id === "=" && state.tokens.next.identifier) {
@@ -4116,8 +4117,6 @@ var JSHINT = (function() {
       }
     }
 
-    state.funct["(breakage)"] += 1;
-    state.funct["(loopage)"] += 1;
     increaseComplexityCount();
     advance("(");
 
@@ -4191,6 +4190,9 @@ var JSHINT = (function() {
         });
       }
 
+      state.funct["(breakage)"] += 1;
+      state.funct["(loopage)"] += 1;
+
       s = block(true, true);
 
       if (nextop.value === "in" && state.option.forin) {
@@ -4239,6 +4241,10 @@ var JSHINT = (function() {
       }
       nolinebreak(state.tokens.curr);
       advance(";");
+
+      // start loopage after the first ; as the next two expressions are executed
+      // on every loop
+      state.funct["(loopage)"] += 1;
       if (state.tokens.next.id !== ";") {
         checkCondAssignment(expression(0));
       }
@@ -4257,6 +4263,7 @@ var JSHINT = (function() {
         }
       }
       advance(")", t);
+      state.funct["(breakage)"] += 1;
       block(true, true);
       state.funct["(breakage)"] -= 1;
       state.funct["(loopage)"] -= 1;

diff --git a/tests/unit/core.js b/tests/unit/core.js
@@ -755,13 +755,33 @@ exports.testUndefinedAssignment = function (test) {
   var src = [
     "var x = undefined;",
     "const y = undefined;",
-    "let z = undefined;"
+    "let z = undefined;",
+    "for(var a = undefined; a < 9; a++) {",
+    "  var b = undefined;", // necessary - see gh-1191
+    "  const c = undefined;",
+    "  let d = undefined;",
+    "  var e = function() {",
+    "    var f = undefined;",
+    "    const g = undefined;",
+    "    let h = undefined;",
+    "  };",
+    "}",
+    "// jshint -W080",
+    "var i = undefined;",
+    "const j = undefined;",
+    "let k = undefined;",
   ];
 
   TestRun(test)
     .addError(1, "It's not necessary to initialize 'x' to 'undefined'.")
     .addError(2, "It's not necessary to initialize 'y' to 'undefined'.")
     .addError(3, "It's not necessary to initialize 'z' to 'undefined'.")
+    .addError(4, "It's not necessary to initialize 'a' to 'undefined'.")
+    .addError(6, "It's not necessary to initialize 'c' to 'undefined'.")
+    .addError(7, "It's not necessary to initialize 'd' to 'undefined'.")
+    .addError(9, "It's not necessary to initialize 'f' to 'undefined'.")
+    .addError(10, "It's not necessary to initialize 'g' to 'undefined'.")
+    .addError(11, "It's not necessary to initialize 'h' to 'undefined'.")
     .test(src, {esnext: true});
 
   test.done();

diff --git a/tests/unit/options.js b/tests/unit/options.js
@@ -1238,6 +1238,18 @@ exports.loopfunc = function (test) {
     .addError(17, "Don't make functions within a loop.")
     .test(es6LoopFuncSrc, {esnext: true});
 
+  // functions declared in the expressions that loop should warn
+  var src2 = [
+    "for(var i = 0; function a(){return i;}; i++) { break; }",
+    "var j;",
+    "while(function b(){return j;}){}",
+    "for(var c = function(){return j;};;){c();}"];
+
+  TestRun(test)
+    .addError(1, "Don't make functions within a loop.")
+    .addError(3, "Don't make functions within a loop.")
+    .test(src2, { es3: true, loopfunc: false, boss: true });
+
   test.done();
 };