fix: restore correct SSR sourcemaps for precompiled JSX

packages/plugin-vite/deno.json

@@ -23,7 +23,7 @@
   "imports": {
     "@babel/core": "npm:@babel/core@^7.28.0",
     "@babel/preset-react": "npm:@babel/preset-react@^7.27.1",
-    "@deno/loader": "jsr:@deno/loader@^0.4.0",
+    "@deno/loader": "jsr:@deno/loader@^0.5.0",
     "@marvinh-test/import-json": "jsr:@marvinh-test/import-json@^0.0.1",
     "@remix-run/node-fetch-server": "npm:@remix-run/node-fetch-server@^0.12.0",
     "@prefresh/vite": "npm:@prefresh/vite@^2.4.8",

packages/plugin-vite/src/plugins/deno.ts

@@ -2,6 +2,7 @@ import type { Plugin } from "vite";
 import {
   type Loader,
   MediaType,
+  type ModuleLoadResponse,
   RequestedModuleType,
   ResolutionMode,
   Workspace,
@@ -17,6 +18,8 @@ const { default: babelReact } = await import("@babel/preset-react");
 
 const BUILTINS = new Set(builtinModules);
 
+const decoder = new TextDecoder();
+
 interface DenoState {
   type: RequestedModuleType;
 }
@@ -180,14 +183,15 @@ export function deno(): Plugin {
           return null;
         }
 
-        const code = new TextDecoder().decode(result.code);
+        const code = decoder.decode(result.code);
 
         const maybeJsx = babelTransform({
           ssr: this.environment.config.consumer === "server",
           media: result.mediaType,
           code,
           id: specifier,
           isDev,
+          inputSourceMap: parseSourceMap(result.sourceMap),
         });
         if (maybeJsx !== null) {
           return maybeJsx;
@@ -224,14 +228,15 @@ export function deno(): Plugin {
         return null;
       }
 
-      const code = new TextDecoder().decode(result.code);
+      const code = decoder.decode(result.code);
 
       const maybeJsx = babelTransform({
         ssr: this.environment.config.consumer === "server",
         media: result.mediaType,
         id,
         code,
         isDev,
+        inputSourceMap: parseSourceMap(result.sourceMap),
       });
       if (maybeJsx) {
         return maybeJsx;
@@ -279,10 +284,12 @@ export function deno(): Plugin {
           return;
         }
 
-        const code = new TextDecoder().decode(result.code);
+        const code = decoder.decode(result.code);
+        const map = parseSourceMap(result.sourceMap);
 
         return {
           code,
+          map,
         };
       },
     },
@@ -375,13 +382,14 @@ function babelTransform(
     code: string;
     id: string;
     isDev: boolean;
+    inputSourceMap: babel.TransformOptions["inputSourceMap"];
   },
 ) {
   if (!isJsMediaType(options.media)) {
     return null;
   }
 
-  const { ssr, code, id, isDev } = options;
+  const { ssr, code, id, isDev, inputSourceMap } = options;
 
   const presets: babel.PluginItem[] = [];
   if (
@@ -400,6 +408,7 @@ function babelTransform(
   const result = babel.transformSync(code, {
     filename: id,
     babelrc: false,
+    inputSourceMap,
     sourceMaps: "both",
     presets: presets,
     plugins: [httpAbsolute(url)],
@@ -415,3 +424,10 @@ function babelTransform(
 
   return null;
 }
+
+function parseSourceMap(
+  sourceMap: ModuleLoadResponse["sourceMap"],
+): babel.TransformOptions["inputSourceMap"] {
+  if (!sourceMap) return undefined;
+  return JSON.parse(decoder.decode(sourceMap));
+}

packages/plugin-vite/tests/build_test.ts

@@ -1,3 +1,5 @@
+import { createLogger } from "vite";
+import type { BabelFileResult } from "@babel/core";
 import { expect } from "@std/expect";
 import { walk } from "@std/fs/walk";
 import {
@@ -13,6 +15,7 @@
   launchProd,
   usingEnv,
 } from "./test_utils.ts";
+import { toPosix } from "fresh/internal-dev";
 import * as path from "@std/path";
 import { FRESH_CSS_PLACEHOLDER } from "../src/plugins/server_snapshot.ts";
 
@@ -592,9 +595,13 @@
   "vite build - custom rollup entryFileNames in server.js",
   async () => {
     await using res = await buildVite(DEMO_DIR, {
-      rollupOutput: {
-        entryFileNames: "[hash].mjs",
-        chunkFileNames: "[hash].mjs",
+      build: {
+        rollupOptions: {
+          output: {
+            entryFileNames: "[hash].mjs",
+            chunkFileNames: "[hash].mjs",
+          },
+        },
       },
     });
 
@@ -828,3 +835,79 @@
     );
   },
 );
+
+integrationTest(
+  "vite build - ssr sourcemap sould be generated collectly",
+  async () => {
+    await using tmp = await buildVite(DEMO_DIR, {
+      environments: {
+        ssr: {
+          build: {
+            sourcemap: true,
+          },
+        },
+      },
+    });
+
+    const serverAssetsDir = path.join(tmp.tmp, "_fresh", "server", "assets");
+    for await (
+      const entry of walk(serverAssetsDir, {
+        exts: [".mjs"],
+        includeDirs: false,
+      })
+    ) {
+      const js = await Deno.readTextFile(entry.path);
+      const match = js.match(/\/\/# sourceMappingURL=(.+)$/m);
+      const mapPath = path.join(path.dirname(entry.path), match![1]);
+      const mapText = await Deno.readTextFile(mapPath);
+      const map: NonNullable<BabelFileResult["map"]> = JSON.parse(mapText);
+
+      // check a specific sourcemap file which contains
+      // the reference of original source file
+      if (entry.name.includes("_fresh-route___tests_feed-")) {
+        expect(
+          map.sources.some((source) =>
+            toPosix(source).endsWith("demo/routes/tests/feed.tsx")
+          ),
+        ).toBe(true);
+      }
+    }
+  },
+);
+
+// rollup specific test
+// https://rollupjs.org/troubleshooting/#warning-sourcemap-is-likely-to-be-incorrect
+// this test could be broke if it will migrate to rolldown
+integrationTest(
+  "vite build - ssr sourcemap sould be generated without warings",
+  async () => {
+    const warnMsgs = new Set<string>();
+    const customLogger = createLogger("error");
+    customLogger.warn = (msg) => {
+      customLogger.hasWarned = true;
+      warnMsgs.add(msg);
+    };
+    customLogger.warnOnce = (msg) => {
+      customLogger.hasWarned = true;
+      warnMsgs.add(msg);
+    };
+
+    await using _ = await buildVite(DEMO_DIR, {
+      logLevel: "warn",
+      clearScreen: true,
+      customLogger,
+      environments: {
+        ssr: {
+          build: {
+            sourcemap: true,
+          },
+        },
+      },
+    });
+
+    const sourceMapIncorrectMsg = warnMsgs.has(
+      "[plugin deno] Sourcemap is likely to be incorrect: a plugin (deno) was used to transform files, but didn't generate a sourcemap for the transformation. Consult the plugin documentation for help",
+    );
+    expect(sourceMapIncorrectMsg).not.toBeTruthy();
+  },
+);

packages/plugin-vite/tests/test_utils.ts

@@ -1,4 +1,4 @@
-import { createBuilder } from "vite";
+import { createBuilder, mergeConfig } from "vite";
 import * as path from "@std/path";
 import { walk } from "@std/fs/walk";
 import { integrationTest, withTmpDir } from "../../fresh/src/test_utils.ts";
@@ -135,34 +135,23 @@ export async function withDevServer(
 
 export async function buildVite(
   fixtureDir: string,
-  options?: {
-    base?: string;
-    rollupOutput?: {
-      entryFileNames?: string;
-      chunkFileNames?: string;
-      assetFileNames?: string;
-    };
-  },
+  config?: Parameters<typeof createBuilder>[0],
 ) {
   const tmp = await withTmpDir({
     dir: path.join(import.meta.dirname!, ".."),
     prefix: "tmp_vite_",
   });
 
-  const builder = await createBuilder({
+  const defaults = {
     logLevel: "error",
     root: fixtureDir,
-    base: options?.base,
     build: {
       emptyOutDir: true,
     },
     environments: {
       ssr: {
         build: {
           outDir: path.join(tmp.dir, "_fresh", "server"),
-          rollupOptions: options?.rollupOutput
-            ? { output: options.rollupOutput }
-            : undefined,
         },
       },
       client: {
@@ -171,7 +160,10 @@ export async function buildVite(
         },
       },
     },
-  });
+  } satisfies Parameters<typeof createBuilder>[0];
+  const builder = await createBuilder(
+    mergeConfig(defaults, config ?? {}),
+  );
   await builder.buildApp();
 
   return {