fix: keep loro-crdt sourcemap sources inside the package (#947) (#987)

Rewrite rollup output `sources` so they resolve inside the published
package and embed `sourcesContent`, removing the Vite/Vitest "source
file outside its package" warning users see for loro-crdt.

Co-authored-by: Zixuan Chen <zx@loro.dev>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 3 people

.changeset/fix-sourcemap-package-boundary.md

@@ -0,0 +1,5 @@
+---
+"loro-crdt": patch
+---
+
+Fix published sourcemap `sources` pointing outside the package. The rollup TypeScript plugin's emitted maps were resolved by rollup against the `.ts` source directory, leaving `../../index.ts` in the published `sources`. Vite/Vitest warned about source files escaping the package. The sourcemap now resolves inside the package and `sourcesContent` is included so debuggers don't need to fetch the TypeScript source.

crates/loro-wasm/rollup.config.mjs

@@ -1,6 +1,34 @@
+import fs from 'node:fs';
+import path from 'node:path';
 import typescript from '@rollup/plugin-typescript';
 import { nodeResolve } from '@rollup/plugin-node-resolve';
 
+const packageRoot = path.resolve();
+
+// Rewrite source paths in the emitted sourcemap so they stay inside the
+// published package. @rollup/plugin-typescript hands rollup a map whose
+// `sources` are relative to TS's intended output location, but rollup
+// resolves them against the .ts module's directory — yielding paths like
+// "../../index.ts" relative to the published sourcemap that escape the
+// package and trigger Vite/Vitest's "source file outside its package"
+// warning when downstream users install loro-crdt. See #947.
+const sourcemapPathTransform = (relativePath, sourcemapPath) => {
+  const sourcemapDir = path.dirname(sourcemapPath);
+  const absoluteSource = path.resolve(sourcemapDir, relativePath);
+  if (absoluteSource.startsWith(packageRoot + path.sep) && fs.existsSync(absoluteSource)) {
+    return relativePath.split(path.sep).join('/');
+  }
+  // The reported path resolves outside the package. Locate the real file
+  // inside the package by basename and produce a path relative to the
+  // sourcemap that stays inside the published tree.
+  const fileName = path.basename(absoluteSource);
+  const candidate = path.resolve(packageRoot, fileName);
+  if (fs.existsSync(candidate)) {
+    return path.relative(sourcemapDir, candidate).split(path.sep).join('/');
+  }
+  return relativePath;
+};
+
 const createConfig = (format, tsTarget, outputDir) => ({
   input: {
     'index': 'index.ts',
@@ -9,6 +37,7 @@ const createConfig = (format, tsTarget, outputDir) => ({
     dir: outputDir,
     format: format,
     sourcemap: true,
+    sourcemapPathTransform,
     entryFileNames: '[name].js',
   },
   plugins: [
@@ -18,6 +47,7 @@ const createConfig = (format, tsTarget, outputDir) => ({
         target: tsTarget,
         declaration: true,
         outDir: outputDir,
+        inlineSources: true,
       },
       exclude: ['tests/**/*', 'vite.config.*']
     }),