Merge branch 'master' of https://github.com/rollup/rollup into sync-6…

…51e4935

CHANGELOG.md

@@ -1,5 +1,17 @@
 # rollup changelog
 
+## 3.27.2
+
+_2023-08-04_
+
+### Bug Fixes
+
+- Revert sourcemap performance improvement for now as it causes issues with Vite (#5075)
+
+### Pull Requests
+
+- [#5075](https://github.com/rollup/rollup/pull/5075): Revert perf(sourcemap): lazy compute decoded mappings (@thebanjomatic)
+
 ## 3.27.1
 
 _2023-08-03_

browser/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@rollup/browser",
-  "version": "3.27.1",
+  "version": "3.27.2",
   "description": "Next-generation ES module bundler browser build",
   "main": "dist/rollup.browser.js",
   "module": "dist/es/rollup.browser.js",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rollup",
-  "version": "3.27.1",
+  "version": "3.27.2",
   "description": "Next-generation ES module bundler",
   "main": "dist/rollup.js",
   "module": "dist/es/rollup.js",

src/Module.ts

@@ -48,7 +48,6 @@ import type {
 } from './rollup/types';
 import { EMPTY_OBJECT } from './utils/blank';
 import { BuildPhase } from './utils/buildPhase';
-import { decodedSourcemap, resetSourcemapCache } from './utils/decodedSourcemap';
 import { getId } from './utils/getId';
 import { getNewSet, getOrCreate } from './utils/getOrCreate';
 import { getOriginalLocation } from './utils/getOriginalLocation';
@@ -818,18 +817,8 @@ export default class Module {
 
 		this.info.code = code;
 		this.originalCode = originalCode;
-
-		// We need to call decodedSourcemap on the input in case they were hydrated from json in the cache and don't
-		// have the lazy evaluation cache configured. Right now this isn't enforced by the type system because the
-		// RollupCache stores `ExistingDecodedSourcemap` instead of `ExistingRawSourcemap`
-		this.originalSourcemap = decodedSourcemap(originalSourcemap);
-		this.sourcemapChain = sourcemapChain.map(mapOrMissing =>
-			mapOrMissing.missing ? mapOrMissing : decodedSourcemap(mapOrMissing)
-		);
-
-		// If coming from cache and this value is already fully decoded, we want to re-encode here to save memory.
-		resetSourcemapCache(this.originalSourcemap, this.sourcemapChain);
-
+		this.originalSourcemap = originalSourcemap;
+		this.sourcemapChain = sourcemapChain;
 		if (transformFiles) {
 			this.transformFiles = transformFiles;
 		}

src/rollup/types.d.ts

@@ -52,7 +52,7 @@ export type SourceMapSegment =
 
 export interface ExistingDecodedSourceMap {
 	file?: string;
-	readonly mappings: SourceMapSegment[][];
+	mappings: SourceMapSegment[][];
 	names: string[];
 	sourceRoot?: string;
 	sources: string[];
@@ -74,10 +74,11 @@ export interface ExistingRawSourceMap {
 
 export type DecodedSourceMapOrMissing =
 	| {
+			mappings?: never;
 			missing: true;
 			plugin: string;
 	  }
-	| (ExistingDecodedSourceMap & { missing?: false });
+	| ExistingDecodedSourceMap;
 
 export interface SourceMap {
 	file: string;

src/utils/collapseSourcemaps.ts

@@ -6,7 +6,6 @@ import type {
 	LogHandler,
 	SourceMapSegment
 } from '../rollup/types';
-import { decodedSourcemap, resetSourcemapCache } from './decodedSourcemap';
 import { LOGLEVEL_WARN } from './logging';
 import { error, logConflictingSourcemapSources, logSourcemapBroken } from './logs';
 import { basename, dirname, relative, resolve } from './path';
@@ -151,7 +150,7 @@ class Link {
 
 function getLinkMap(log: LogHandler) {
 	return function linkMap(source: Source | Link, map: DecodedSourceMapOrMissing): Link {
-		if (!map.missing) {
+		if (map.mappings) {
 			return new Link(map, [source]);
 		}
 
@@ -225,10 +224,6 @@ export function collapseSourcemaps(
 
 	sourcesContent = (excludeContent ? null : sourcesContent) as string[];
 
-	for (const module of modules) {
-		resetSourcemapCache(module.originalSourcemap, module.sourcemapChain);
-	}
-
 	return new SourceMap({ file, mappings, names, sources, sourcesContent });
 }
 
@@ -251,5 +246,5 @@ export function collapseSourcemap(
 		getLinkMap(log)
 	) as Link;
 	const map = source.traceMappings();
-	return decodedSourcemap({ version: 3, ...map });
+	return { version: 3, ...map };
 }

src/utils/decodedSourcemap.ts

@@ -1,57 +1,12 @@
-import { decode, encode } from '@jridgewell/sourcemap-codec';
+import { decode } from '@jridgewell/sourcemap-codec';
 import type {
-	DecodedSourceMapOrMissing,
 	ExistingDecodedSourceMap,
 	ExistingRawSourceMap,
 	SourceMapInput
 } from '../rollup/types';
 
 type Input = SourceMapInput | ExistingDecodedSourceMap | undefined;
 
-interface CachedSourcemapData {
-	encodedMappings: string | undefined;
-	decodedMappings: ExistingDecodedSourceMap['mappings'] | undefined;
-}
-
-const sourceMapCache = new WeakMap<ExistingDecodedSourceMap, CachedSourcemapData>();
-
-/**
- * This clears the decoded array and falls back to the encoded string form.
- * Sourcemap mappings arrays can be very large and holding on to them for longer
- * than is necessary leads to poor heap utilization.
- */
-function resetCacheToEncoded(cache: CachedSourcemapData) {
-	if (cache.encodedMappings === undefined && cache.decodedMappings) {
-		cache.encodedMappings = encode(cache.decodedMappings);
-	}
-	cache.decodedMappings = undefined;
-}
-
-export function resetSourcemapCache(
-	map: ExistingDecodedSourceMap | null,
-	sourcemapChain?: DecodedSourceMapOrMissing[]
-) {
-	if (map) {
-		const cache = sourceMapCache.get(map);
-		if (cache) {
-			resetCacheToEncoded(cache);
-		}
-	}
-
-	if (!sourcemapChain) {
-		return;
-	}
-
-	for (const map of sourcemapChain) {
-		if (map.missing) continue;
-
-		resetSourcemapCache(map);
-	}
-}
-
-export function decodedSourcemap(map: null | undefined): null;
-export function decodedSourcemap(map: Exclude<Input, null | undefined>): ExistingDecodedSourceMap;
-export function decodedSourcemap(map: Input): ExistingDecodedSourceMap | null;
 export function decodedSourcemap(map: Input): ExistingDecodedSourceMap | null {
 	if (!map) return null;
 
@@ -67,33 +22,7 @@ export function decodedSourcemap(map: Input): ExistingDecodedSourceMap | null {
 		};
 	}
 
-	const originalMappings = map.mappings;
-	const isAlreadyDecoded = typeof originalMappings !== 'string';
-	const cache = {
-		decodedMappings: isAlreadyDecoded ? originalMappings : undefined,
-		encodedMappings: isAlreadyDecoded ? undefined : originalMappings
-	};
-
-	const decodedMap = {
-		...(map as ExistingRawSourceMap | ExistingDecodedSourceMap),
-		// By moving mappings behind an accessor, we can avoid unneeded computation for cases
-		// where the mappings field is never actually accessed. This appears to greatly reduce
-		// the overhead of sourcemap decoding in terms of both compute time and memory usage.
-		get mappings() {
-			if (cache.decodedMappings) {
-				return cache.decodedMappings;
-			}
-			// If decodedMappings doesn't exist then encodedMappings should.
-			// The only scenario where cache.encodedMappings should be undefined is if the map
-			// this was constructed from was already decoded, or if mappings was set to a new
-			// decoded string. In either case, this line shouldn't get hit.
-			cache.decodedMappings = decode(cache.encodedMappings!);
-			cache.encodedMappings = undefined;
-			return cache.decodedMappings;
-		}
-	};
-
-	sourceMapCache.set(decodedMap, cache);
+	const mappings = typeof map.mappings === 'string' ? decode(map.mappings) : map.mappings;
 
-	return decodedMap;
+	return { ...(map as ExistingRawSourceMap | ExistingDecodedSourceMap), mappings };
 }

src/utils/getOriginalLocation.ts

@@ -5,7 +5,7 @@ export function getOriginalLocation(
 	location: { column: number; line: number }
 ): { column: number; line: number } {
 	const filteredSourcemapChain = sourcemapChain.filter(
-		(sourcemap): sourcemap is ExistingDecodedSourceMap => !sourcemap.missing
+		(sourcemap): sourcemap is ExistingDecodedSourceMap => !!sourcemap.mappings
 	);
 	traceSourcemap: while (filteredSourcemapChain.length > 0) {
 		const sourcemap = filteredSourcemapChain.pop()!;