Ignore calc() in length-zero-no-unit

lib/rules/length-zero-no-unit/README.md

@@ -1,6 +1,6 @@
 # length-zero-no-unit
 
-Disallow units for zero lengths.
+Disallow units for zero lengths. Ignores `calc` value in favor of `function-calc-no-invalid` rule.
 
 ```css
 a { top: 0px; }

lib/rules/length-zero-no-unit/__tests__/index.js

@@ -12,6 +12,22 @@ testRule(rule, {
       code: "a { top: 0; }",
       description: "unitless zero"
     },
+    {
+      description: "ignore calc",
+      code: "a { padding: calc(0px +\n 0px); }"
+    },
+    {
+      description: "ignore calc. insensitive",
+      code: "a { padding: cAlc(0px + 0px); }"
+    },
+    {
+      description: "ignore calc. empty calc",
+      code: "a { padding: calc(); }"
+    },
+    {
+      description: "ignore calc. several `calc`s",
+      code: "a { padding: calc(1in + 0in * 2)) 0 calc(0px) 0 }"
+    },
     {
       code: "a { padding: 0 /* 0px */; }",
       description: "united zero in comment"
@@ -247,12 +263,13 @@ testRule(rule, {
       column: 27
     },
     {
-      code: "a { padding: calc(1in + 0in * 2)); }",
-      fixed: "a { padding: calc(1in + 0 * 2)); }",
+      description: "ignore calc. has another zero units",
+      code: "a { padding: calc(1in + 0in * 2)) 0in calc(0px) 0px }",
+      fixed: "a { padding: calc(1in + 0in * 2)) 0 calc(0px) 0 }",
 
       message: messages.rejected,
       line: 1,
-      column: 26
+      column: 36
     },
     {
       code: "@media (min-width: 0px) {}",

lib/rules/length-zero-no-unit/index.js

@@ -3,6 +3,7 @@
 const _ = require("lodash");
 const beforeBlockString = require("../../utils/beforeBlockString");
 const blurComments = require("../../utils/blurComments");
+const getMathFunctionsRanges = require("../../utils/getMathFunctionsRanges");
 const hasBlock = require("../../utils/hasBlock");
 const isCustomProperty = require("../../utils/isCustomProperty");
 const keywordSets = require("../../reference/keywordSets");
@@ -28,7 +29,10 @@ const rule = function(actual, secondary, context) {
     }
 
     root.walkDecls(decl => {
-      check(blurComments(decl.toString()), decl);
+      const stringValue = blurComments(decl.toString());
+      const ignorableRanges = getMathFunctionsRanges(stringValue);
+
+      check(stringValue, decl, ignorableRanges);
     });
 
     root.walkAtRules(atRule => {
@@ -39,17 +43,21 @@ const rule = function(actual, secondary, context) {
       check(source, atRule);
     });
 
-    function check(value, node) {
-      const ignorableIndexes = new Set();
-      const fixPositions = [];
-
+    function check(value, node, ignorableRanges = []) {
       if (
         optionsMatches(secondary, "ignore", "custom-properties") &&
         isCustomProperty(value)
       ) {
         return;
       }
 
+      const ignorableIndexes = new Array(value.length).fill(false);
+      const fixPositions = [];
+
+      ignorableRanges.forEach(([start, end]) => {
+        for (let i = start; i < end; i++) ignorableIndexes[i] = true;
+      });
+
       styleSearch({ source: value, target: "0" }, match => {
         const index = match.startIndex;
 
@@ -66,7 +74,7 @@ const rule = function(actual, secondary, context) {
         //
         // This check prevents that from happening: we build and check against a
         // Set containing all the indexes that are part of a value already validated.
-        if (ignorableIndexes.has(index)) {
+        if (ignorableIndexes[index]) {
           return;
         }
 
@@ -110,8 +118,8 @@ const rule = function(actual, secondary, context) {
 
         // Add the indexes to ignorableIndexes so the same value will not
         // be checked multiple times.
-        _.range(valueWithZeroStart, valueWithZeroEnd).forEach(i =>
-          ignorableIndexes.add(i)
+        _.range(valueWithZeroStart, valueWithZeroEnd).forEach(
+          i => (ignorableIndexes[i] = true)
         );
 
         // Only pay attention if the value parses to 0

lib/utils/getMathFunctionsRanges.js

@@ -0,0 +1,18 @@
+"use strict";
+
+const MATH_FUNCTIONS = ["calc"];
+const MATH_FUNCTIONS_REGEXP = new RegExp(
+  `(?:${MATH_FUNCTIONS.join("|")})` + "\\([^()]*(?:\\(.*\\))*[^()]*\\)",
+  "gi"
+);
+
+module.exports = function getMathFunctionsRanges(valueString) {
+  const result = [];
+  let current;
+
+  while ((current = MATH_FUNCTIONS_REGEXP.exec(valueString)) !== null) {
+    result.push([current.index, current.index + current[0].length]);
+  }
+
+  return result;
+};