Fix no-duplicate-at-import-rules false negatives for imports with supports and layer conditions

.changeset/nasty-shoes-bathe.md

@@ -0,0 +1,5 @@
+---
+"stylelint": patch
+---
+
+Fixed: `no-duplicate-at-import-rules` false negatives for imports with `supports` and `layer` conditions

lib/rules/no-duplicate-at-import-rules/__tests__/index.js

@@ -31,6 +31,15 @@ testRule({
 		{
 			code: '@IMPORT "a.css"; @ImPoRt "b.css";',
 		},
+		{
+			code: '@import "a.css" supports(display: flex) tv; @import "a.css" layer tv;',
+		},
+		{
+			code: '@import "a.css" supports(display: flex); @import "a.css" layer;',
+		},
+		{
+			code: '@import "a.css" supports(display: flex) tv; @import "a.css" supports(display: grid) tv;',
+		},
 	],
 
 	reject: [
@@ -114,5 +123,85 @@ testRule({
 			line: 1,
 			column: 18,
 		},
+		{
+			code: '@import url("a.css") layer; @import url("a.css") layer;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 29,
+			endLine: 1,
+			endColumn: 55,
+		},
+		{
+			code: '@import url("a.css") layer(base); @import url("a.css") layer(base);',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 35,
+			endLine: 1,
+			endColumn: 67,
+		},
+		{
+			code: '@import url("a.css") layer(base) supports(display: grid); @import url("a.css") layer(base) supports(display: grid);',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 59,
+			endLine: 1,
+			endColumn: 115,
+		},
+		{
+			code: '@import url("a.css") supports(display: grid); @import url("a.css") supports(display: grid);',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 47,
+			endLine: 1,
+			endColumn: 91,
+		},
+		{
+			code: '@import url("a.css") layer tv; @import url("a.css") layer tv;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 32,
+			endLine: 1,
+			endColumn: 61,
+		},
+		{
+			code: '@import url("a.css") layer(base) tv; @import url("a.css") layer(base) tv;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 38,
+			endLine: 1,
+			endColumn: 73,
+		},
+		{
+			code: '@import url("a.css") layer(base) supports(display: grid) tv; @import url("a.css") layer(base) supports(display: grid) tv;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 62,
+			endLine: 1,
+			endColumn: 121,
+		},
+		{
+			code: '@import url("a.css") layer(base) supports(display: grid) screen, tv; @import url("a.css") layer(base) supports(display: grid) tv;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 70,
+			endLine: 1,
+			endColumn: 129,
+		},
+		{
+			code: '@import url("a.css") layer; @import url("a.css") layer;',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 29,
+			endLine: 1,
+			endColumn: 55,
+		},
+		{
+			code: '@import url("a.css") supports(display: grid); @import url("a.css") supports(display: grid);',
+			message: messages.rejected(`a.css`),
+			line: 1,
+			column: 47,
+			endLine: 1,
+			endColumn: 91,
+		},
 	],
 });

lib/rules/no-duplicate-at-import-rules/index.js

@@ -70,18 +70,31 @@ const rule = (primary) => {
 	};
 };
 
+/** @typedef { import('postcss-value-parser').Node } Node */
+
+/**
+ * @param {Node | Array<Node>} node
+ * @returns {string}
+ */
+function stringifyCondition(node) {
+	// remove whitespace to get a more consistent key
+	return valueParser.stringify(node).replace(/\s/g, '');
+}
+
 /**
  * List the import conditions found in the prelude of an `@import` rule
  *
  * @param {Node[]} params
- * @typedef {import('postcss-value-parser').Node} Node
  * @returns {Array<string>}
  */
 function listImportConditions(params) {
 	if (!params.length) return [];
 
-	/** @type {Array<String>} */
-	let media = [];
+	const separator = ' ';
+	/** @type {Array<string>} */
+	const sharedConditions = [];
+	/** @type {Array<string>} */
+	const media = [];
 	/** @type {Array<Node>} */
 	let lastMediaQuery = [];
 
@@ -91,8 +104,23 @@ function listImportConditions(params) {
 			continue;
 		}
 
+		// layer and supports conditions must precede media query conditions
+		if (!media.length) {
+			// @import url(...) layer(base) supports(display: flex)
+			if (param.type === 'function' && (param.value === 'supports' || param.value === 'layer')) {
+				sharedConditions.push(stringifyCondition(param));
+				continue;
+			}
+
+			// @import url(...) layer
+			if (param.type === 'word' && param.value === 'layer') {
+				sharedConditions.push(stringifyCondition(param));
+				continue;
+			}
+		}
+
 		if (param.type === 'div' && param.value === ',') {
-			media.push(valueParser.stringify(lastMediaQuery));
+			media.push(stringifyCondition(lastMediaQuery));
 			lastMediaQuery = [];
 			continue;
 		}
@@ -101,11 +129,24 @@ function listImportConditions(params) {
 	}
 
 	if (lastMediaQuery.length) {
-		media.push(valueParser.stringify(lastMediaQuery));
+		media.push(stringifyCondition(lastMediaQuery));
+	}
+
+	// Only media query conditions
+	if (media.length && !sharedConditions.length) {
+		return media;
 	}
 
-	// remove remaining whitespace to get a more consistent key
-	return media.map((m) => m.replace(/\s/g, ''));
+	// Only layer and supports conditions
+	if (!media.length && sharedConditions.length) {
+		return [sharedConditions.join(separator)];
+	}
+
+	const sharedConditionsString = sharedConditions.join(separator);
+
+	return media.map((m) => {
+		return sharedConditionsString + separator + m;
+	});
 }
 
 rule.ruleName = ruleName;