don't localize imported values in selectors

index.js

@@ -3,9 +3,24 @@
 const postcss = require('postcss');
 const selectorParser = require('postcss-selector-parser');
 const valueParser = require('postcss-value-parser');
+const { extractICSS } = require('icss-utils');
 
 const isSpacing = node => node.type === 'combinator' && node.value === ' ';
 
+function getImportLocalAliases(icssImports) {
+  const localAliases = new Map();
+  Object.keys(icssImports).forEach(key => {
+    Object.keys(icssImports[key]).forEach(prop => {
+      localAliases.set(prop, icssImports[key][prop]);
+    });
+  });
+  return localAliases;
+}
+
+function maybeLocalizeValue(value, localAliasMap) {
+  if (localAliasMap.has(value)) return value;
+}
+
 function normalizeNodeArray(nodes) {
   const array = [];
 
@@ -25,7 +40,7 @@ function normalizeNodeArray(nodes) {
   return array;
 }
 
-function localizeNode(rule, mode, options) {
+function localizeNode(rule, mode, localAliasMap) {
   const isScopePseudo = node =>
     node.value === ':local' || node.value === ':global';
 
@@ -191,7 +206,14 @@ function localizeNode(rule, mode, options) {
       }
       case 'id':
       case 'class': {
-        if (!context.global) {
+        if (context.global) {
+          break;
+        }
+
+        const isImportedValue = localAliasMap.has(node.value);
+        const isImportedWithExplicitScope = isImportedValue && context.explicit;
+
+        if (!isImportedValue || isImportedWithExplicitScope) {
           const innerNode = node.clone();
           innerNode.spaces = { before: '', after: '' };
 
@@ -231,8 +253,10 @@ function localizeDeclNode(node, context) {
   switch (node.type) {
     case 'word':
       if (context.localizeNextItem) {
-        node.value = ':local(' + node.value + ')';
-        context.localizeNextItem = false;
+        if (!context.localAliasMap.has(node.value)) {
+          node.value = ':local(' + node.value + ')';
+          context.localizeNextItem = false;
+        }
       }
       break;
 
@@ -360,6 +384,7 @@ function localizeAnimationShorthandDeclValues(decl, context) {
       options: context.options,
       global: context.global,
       localizeNextItem: shouldParseAnimationName && !context.global,
+      localAliasMap: context.localAliasMap,
     };
     return localizeDeclNode(node, subContext);
   });
@@ -374,6 +399,7 @@ function localizeDeclValues(localize, decl, context) {
       options: context.options,
       global: context.global,
       localizeNextItem: localize && !context.global,
+      localAliasMap: context.localAliasMap,
     };
     nodes[index] = localizeDeclNode(node, subContext);
   });
@@ -423,6 +449,9 @@ module.exports = postcss.plugin('postcss-modules-local-by-default', function(
   const globalMode = options && options.mode === 'global';
 
   return function(css) {
+    const { icssImports } = extractICSS(css, false);
+    const localAliasMap = getImportLocalAliases(icssImports);
+
     css.walkAtRules(function(atrule) {
       if (/keyframes$/i.test(atrule.name)) {
         const globalMatch = /^\s*:global\s*\((.+)\)\s*$/.exec(atrule.params);
@@ -440,10 +469,12 @@ module.exports = postcss.plugin('postcss-modules-local-by-default', function(
           atrule.params = localMatch[0];
           globalKeyframes = false;
         } else if (!globalMode) {
-          atrule.params = ':local(' + atrule.params + ')';
+          if (atrule.params && !localAliasMap.has(atrule.params))
+            atrule.params = ':local(' + atrule.params + ')';
         }
         atrule.walkDecls(function(decl) {
           localizeDecl(decl, {
+            localAliasMap,
             options: options,
             global: globalKeyframes,
           });
@@ -452,6 +483,7 @@ module.exports = postcss.plugin('postcss-modules-local-by-default', function(
         atrule.nodes.forEach(function(decl) {
           if (decl.type === 'decl') {
             localizeDecl(decl, {
+              localAliasMap,
               options: options,
               global: globalMode,
             });
@@ -478,9 +510,10 @@ module.exports = postcss.plugin('postcss-modules-local-by-default', function(
         return;
       }
 
-      const context = localizeNode(rule, options.mode);
+      const context = localizeNode(rule, options.mode, localAliasMap);
 
       context.options = options;
+      context.localAliasMap = localAliasMap;
 
       if (pureMode && context.hasPureGlobals) {
         throw rule.error(

package.json

@@ -23,6 +23,7 @@
     "trailingComma": "es5"
   },
   "dependencies": {
+    "icss-utils": "^4.0.0",
     "postcss": "^7.0.6",
     "postcss-selector-parser": "^6.0.0",
     "postcss-value-parser": "^3.3.1"

test.js

@@ -529,8 +529,92 @@ const tests = [
   },
   {
     should: 'not ignore custom property set',
-    input: ':root { --title-align: center; --sr-only: { position: absolute; } }',
-    expected: ':root { --title-align: center; --sr-only: { position: absolute; } }',
+    input:
+      ':root { --title-align: center; --sr-only: { position: absolute; } }',
+    expected:
+      ':root { --title-align: center; --sr-only: { position: absolute; } }',
+  },
+  /**
+   * Imported aliases
+   */
+  {
+    should: 'not localize imported alias',
+    input: `
+      :import(foo) { a_value: some-value; }
+
+      .foo > .a_value { }
+    `,
+    expected: `
+      :import(foo) { a_value: some-value; }
+
+      :local(.foo) > .a_value { }
+    `,
+  },
+  {
+    should: 'not localize nested imported alias',
+    input: `
+      :import(foo) { a_value: some-value; }
+
+      .foo > .a_value > .bar { }
+    `,
+    expected: `
+      :import(foo) { a_value: some-value; }
+
+      :local(.foo) > .a_value > :local(.bar) { }
+    `,
+  },
+
+  {
+    should: 'ignore imported in explicit local',
+    input: `
+      :import(foo) { a_value: some-value; }
+
+      :local(.a_value) { }
+    `,
+    expected: `
+      :import(foo) { a_value: some-value; }
+
+      :local(.a_value) { }
+    `,
+  },
+  {
+    should: 'escape local context with explict global',
+    input: `
+      :import(foo) { a_value: some-value; }
+
+      :local .foo :global(.a_value) .bar { }
+    `,
+    expected: `
+      :import(foo) { a_value: some-value; }
+
+      :local(.foo) .a_value :local(.bar) { }
+    `,
+  },
+  {
+    should: 'respect explicit local',
+    input: `
+      :import(foo) { a_value: some-value; }
+
+      .a_value :local .a_value .foo :global .a_value { }
+    `,
+    expected: `
+      :import(foo) { a_value: some-value; }
+
+      .a_value :local(.a_value) :local(.foo) .a_value { }
+    `,
+  },
+  {
+    should: 'not localize imported animation-name',
+    input: `
+      :import(file) { a_value: some-value; }
+
+      .foo { animation-name: a_value; }
+    `,
+    expected: `
+      :import(file) { a_value: some-value; }
+
+      :local(.foo) { animation-name: a_value; }
+    `,
   },
 ];
 

yarn.lock

@@ -1221,6 +1221,13 @@ iconv-lite@^0.4.24, iconv-lite@^0.4.4:
   dependencies:
     safer-buffer ">= 2.1.2 < 3"
 
+icss-utils@^4.0.0:
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/icss-utils/-/icss-utils-4.0.0.tgz#d52cf4bcdcfa1c45c2dbefb4ffdf6b00ef608098"
+  integrity sha512-bA/xGiwWM17qjllIs9X/y0EjsB7e0AV08F3OL8UPsoNkNRibIuu8f1eKTnQ8QO1DteKKTxTUAn+IEWUToIwGOA==
+  dependencies:
+    postcss "^7.0.5"
+
 ignore-walk@^3.0.1:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/ignore-walk/-/ignore-walk-3.0.1.tgz#a83e62e7d272ac0e3b551aaa82831a19b69f82f8"
@@ -2098,7 +2105,7 @@ postcss-value-parser@^3.3.1:
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-3.3.1.tgz#9ff822547e2893213cf1c30efa51ac5fd1ba8281"
   integrity sha512-pISE66AbVkp4fDQ7VHBwRNXzAAKJjw4Vw7nWI/+Q3vuly7SNfgYXvm6i5IgFylHGK5sP/xHAbB7N49OS4gWNyQ==
 
-postcss@^7.0.6:
+postcss@^7.0.5, postcss@^7.0.6:
   version "7.0.14"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.14.tgz#4527ed6b1ca0d82c53ce5ec1a2041c2346bbd6e5"
   integrity sha512-NsbD6XUUMZvBxtQAJuWDJeeC4QFsmWsfozWxCJPWf3M55K9iu2iMDaKqyoOdTJ1R4usBXuxlVFAIo8rZPQD4Bg==