Merge pull request #570 from stof/rule_dollar_variable_no_namespace

Implement the dollar-variable-no-namespaced-assignment rule

README.md

@@ -114,6 +114,7 @@ Please also see the [example configs](./docs/examples/) for special cases.
 - [`dollar-variable-empty-line-before`](./src/rules/dollar-variable-empty-line-before/README.md): Require a single empty line or disallow empty lines before `$`-variable declarations (Autofixable).
 - [`dollar-variable-first-in-block`](./src/rules/dollar-variable-first-in-block/README.md): Require for variables to be put first in a block (a rule or in root).
 - [`dollar-variable-no-missing-interpolation`](./src/rules/dollar-variable-no-missing-interpolation/README.md): Disallow Sass variables that are used without interpolation with CSS features that use custom identifiers.
+- [`dollar-variable-no-namespaced-assignment`](./src/rules/dollar-variable-no-namespaced-assignment/README.md): Disallow assignment to namespaced Sass variables.
 - [`dollar-variable-pattern`](./src/rules/dollar-variable-pattern/README.md): Specify a pattern for Sass-like variables.
 
 ### `%`-placeholder

src/rules/dollar-variable-no-namespaced-assignment/README.md

@@ -0,0 +1,24 @@
+# dollar-variable-no-namespaced-assignment
+
+Disallow assignment to namespaced variables. 
+
+```scss
+a { imported.$foo: 1px; }
+/** ↑
+ * This assignment */
+```
+
+## Examples
+
+The following patterns are considered warnings:
+
+```scss
+imported.$foo: 1;
+```
+
+The following patterns are *not* considered warnings:
+
+```scss
+a { b: imported.$foo-bar; }
+a { $foo: 0; }
+```

src/rules/dollar-variable-no-namespaced-assignment/__tests__/index.js

@@ -0,0 +1,39 @@
+import { messages, ruleName } from "..";
+
+testRule({
+  ruleName,
+  config: [true],
+  customSyntax: "postcss-scss",
+
+  accept: [
+    {
+      code: `
+      p {
+        $foo: 10px;
+      }
+    `,
+      description: "Non-namespaced assignment"
+    },
+    {
+      code: `
+      p {
+        a: imported.$foo;
+      }
+    `,
+      description: "Namespaced usage"
+    }
+  ],
+
+  reject: [
+    {
+      code: `
+      p {
+        imported.$foo: 10px;
+      }
+    `,
+      line: 3,
+      message: messages.rejected,
+      description: "Namespaced assignment"
+    }
+  ]
+});

src/rules/dollar-variable-no-namespaced-assignment/index.js

@@ -0,0 +1,31 @@
+import { utils } from "stylelint";
+import { namespace } from "../../utils";
+
+export const ruleName = namespace("dollar-variable-no-namespaced-assignment");
+
+export const messages = utils.ruleMessages(ruleName, {
+  rejected: "Unexpected assignment to a namespaced $ variable"
+});
+
+export default function(actual) {
+  return (root, result) => {
+    const validOptions = utils.validateOptions(result, ruleName, { actual });
+
+    if (!validOptions) {
+      return;
+    }
+
+    root.walkDecls(decl => {
+      if (!/^[^$.]+\.\$./.test(decl.prop)) {
+        return;
+      }
+
+      utils.report({
+        message: messages.rejected,
+        node: decl,
+        result,
+        ruleName
+      });
+    });
+  };
+}

src/rules/index.js

@@ -34,6 +34,7 @@ import dollarVariableEmptyLineAfter from "./dollar-variable-empty-line-after";
 import dollarVariableEmptyLineBefore from "./dollar-variable-empty-line-before";
 import dollarVariableFirstInBlock from "./dollar-variable-first-in-block";
 import dollarVariableNoMissingInterpolation from "./dollar-variable-no-missing-interpolation";
+import dollarVariableNoNamespacedAssignment from "./dollar-variable-no-namespaced-assignment";
 import dollarVariablePattern from "./dollar-variable-pattern";
 import doubleSlashCommentEmptyLineBefore from "./double-slash-comment-empty-line-before";
 import doubleSlashCommentInline from "./double-slash-comment-inline";
@@ -93,6 +94,7 @@ export default {
   "dollar-variable-empty-line-before": dollarVariableEmptyLineBefore,
   "dollar-variable-first-in-block": dollarVariableFirstInBlock,
   "dollar-variable-no-missing-interpolation": dollarVariableNoMissingInterpolation,
+  "dollar-variable-no-namespaced-assignment": dollarVariableNoNamespacedAssignment,
   "dollar-variable-pattern": dollarVariablePattern,
   "double-slash-comment-empty-line-before": doubleSlashCommentEmptyLineBefore,
   "double-slash-comment-inline": doubleSlashCommentInline,