fix some specificity stuff

Author: Rich-Harris

packages/svelte/src/compiler/phases/2-analyze/css/css-analyze.js

@@ -73,6 +73,12 @@ const analysis_visitors = {
 			...context.state,
 			rule: node
 		});
+
+		node.metadata.has_local_selectors = node.prelude.children.some((selector) => {
+			return selector.children.some(
+				({ metadata }) => !metadata.is_global && !metadata.is_host && !metadata.is_root
+			);
+		});
 	}
 };
 

packages/svelte/src/compiler/phases/3-transform/css/index.js

@@ -172,10 +172,20 @@ const visitors = {
 
 		// if this selector list belongs to a rule, require a specificity bump for the
 		// first scoped selector but only if we're at the top level
-		// TODO this isn't quite right, it would break with `:global(x) {...}`
-		const parent = path.at(-1);
+		let parent = path.at(-1);
 		if (parent?.type === 'Rule') {
-			specificity = { bumped: !!parent.metadata.parent_rule };
+			specificity = { bumped: false };
+
+			/** @type {import('#compiler').Css.Rule | null} */
+			let rule = parent.metadata.parent_rule;
+
+			while (rule) {
+				if (rule.metadata.has_local_selectors) {
+					specificity = { bumped: true };
+					break;
+				}
+				rule = rule.metadata.parent_rule;
+			}
 		}
 
 		next({ ...state, specificity });

packages/svelte/src/compiler/types/css.ts

@@ -27,6 +27,7 @@ export interface Rule extends BaseNode {
 	block: Block;
 	metadata: {
 		parent_rule: null | Rule;
+		has_local_selectors: boolean;
 	};
 }