Avoid filename conflict (vercel/turborepo#3673)

We need to make sure that `.json` and `.json.js` doesn't end up with the
same name.

Author: sokra

crates/turbopack-core/src/chunk/dev.rs

@@ -123,7 +123,8 @@ impl ChunkingContext for DevChunkingContext {
         } else {
             clean(&path_vc.to_string().await?)
         };
-        if name.ends_with(extension) {
+        let removed_extension = name.ends_with(extension);
+        if removed_extension {
             name.truncate(name.len() - extension.len());
         }
 
@@ -148,9 +149,13 @@ impl ChunkingContext for DevChunkingContext {
             let truncated_hash = &hash[..5];
             name = format!("{}_{}", truncated_hash, &name[i..]);
         }
-        if !name.ends_with(extension) {
-            name += extension;
+        // We need to make sure that `.json` and `.json.js` doesn't end up with the same
+        // name. So when we add an extra extension when want to mark that with a "._"
+        // suffix.
+        if !removed_extension {
+            name += "._";
         }
+        name += extension;
         let mut root_path = self.chunk_root_path;
         #[allow(clippy::single_match, reason = "future extensions")]
         match extension {

crates/turbopack-tests/tests/snapshot/css/css/output/8697f_foo_style.module.css.js renamed to crates/turbopack-tests/tests/snapshot/css/css/output/8697f_foo_style.module.css._.js

@@ -3,7 +3,7 @@
 "[project]/crates/turbopack-tests/tests/snapshot/imports/dynamic/input/vercel.mjs/manifest-chunk.js": (({ r: __turbopack_require__, x: __turbopack_external_require__, i: __turbopack_import__, s: __turbopack_esm__, v: __turbopack_export_value__, c: __turbopack_cache__, l: __turbopack_load__, j: __turbopack_cjs__, p: process, g: global, __dirname }) => (() => {
 
 const chunks = [
-    "output/crates_turbopack-tests_tests_snapshot_imports_dynamic_input_vercel.mjs.js",
+    "output/crates_turbopack-tests_tests_snapshot_imports_dynamic_input_vercel.mjs._.js",
 ];
 
 __turbopack_export_value__(Promise.all(chunks.map(__turbopack_load__)));