fix csstools/postcss-nesting#82: use the RuleExit listener (csstools/…

…postcss-nesting#86)

plugins/postcss-nesting/.bin/test-tape.js

@@ -19,17 +19,30 @@ export default async function tape() {
 	failures += await test('ignores invalid entries', { basename: 'ignore' })
 	failures += await test('supports complex entries', { basename: 'complex' })
 
+	let mixinPlugin = () => {
+		return {
+			postcssPlugin: 'mixin',
+			AtRule: {
+				mixin(node) {
+					node.replaceWith('& .in{ &.deep { color: blue; }}')
+				},
+			},
+		}
+	}
+	mixinPlugin.postcss = true
+	failures += await test('supports other visitors', { basename: 'mixin' }, mixinPlugin)
+
 	return failures === 0
 }
 
-async function test(name, init) {
+async function test(name, init, ...plugins) {
 	const { basename } = Object(init)
 
 	let sourceUrl = new URL(`test/${basename}.css`, workingUrl)
 	let expectUrl = new URL(`test/${basename}.expect.css`, workingUrl)
 	let resultUrl = new URL(`test/${basename}.result.css`, workingUrl)
 
-	let plugins = [plugin]
+	plugins.unshift(plugin)
 
 	let sourceCss = await fs.readFile(sourceUrl, 'utf8')
 	let expectCss = await fs.readFile(expectUrl, 'utf8')
@@ -49,10 +62,9 @@ async function test(name, init) {
 	}
 }
 
-
 if (new URL(process.argv[1], 'file:').href === import.meta.url) {
 	tape().then(
 		() => process.exit(0),
-		() => process.exit(1)
+		() => process.exit(1),
 	)
 }

plugins/postcss-nesting/src/lib/walk.js

@@ -4,21 +4,19 @@ import transformAtruleWithinRule, { isAtruleWithinRule } from './atrule-within-r
 import transformAtruleWithinAtrule, { isAtruleWithinAtrule } from './atrule-within-atrule.js'
 
 export default function walk(node) {
-	node.nodes.slice(0).forEach((child) => {
-		if (child.parent === node) {
-			if (isRuleWithinRule(child)) {
-				transformRuleWithinRule(child)
-			} else if (isNestRuleWithinRule(child)) {
-				transformNestRuleWithinRule(child)
-			} else if (isAtruleWithinRule(child)) {
-				transformAtruleWithinRule(child)
-			} else if (isAtruleWithinAtrule(child)) {
-				transformAtruleWithinAtrule(child)
-			}
+	node.each((child) => {
+		if (isRuleWithinRule(child)) {
+			transformRuleWithinRule(child)
+		} else if (isNestRuleWithinRule(child)) {
+			transformNestRuleWithinRule(child)
+		} else if (isAtruleWithinRule(child)) {
+			transformAtruleWithinRule(child)
+		} else if (isAtruleWithinAtrule(child)) {
+			transformAtruleWithinAtrule(child)
+		}
 
-			if (Object(child.nodes).length) {
-				walk(child)
-			}
+		if (Object(child.nodes).length) {
+			walk(child)
 		}
 	})
 }

plugins/postcss-nesting/src/postcss-8-nesting.js

@@ -3,8 +3,8 @@ import walk from './lib/walk.js'
 export default function postcssNesting() {
 	return {
 		postcssPlugin: 'postcss-nesting',
-		Once(root) {
-			walk(root)
+		RuleExit(rule) {
+			walk(rule)
 		},
 	}
 }

plugins/postcss-nesting/test/mixin.css

@@ -0,0 +1,6 @@
+a {
+	& b {
+		color: red;
+	}
+	@mixin;
+}

plugins/postcss-nesting/test/mixin.expect.css

@@ -0,0 +1,5 @@
+
+	a b {
+		color: red;
+	}
+a .in.deep { color: blue; }