fix: sourceMapFilename is relative (#8269)

crates/rspack_plugin_devtool/Cargo.toml

@@ -14,7 +14,6 @@ dashmap                  = { workspace = true }
 derivative               = { workspace = true }
 futures                  = { workspace = true }
 itertools                = { workspace = true }
-pathdiff                 = { workspace = true }
 rayon                    = { workspace = true }
 regex                    = { workspace = true }
 rspack_base64            = { version = "0.1.0", path = "../rspack_base64" }

crates/rspack_plugin_devtool/src/source_map_dev_tool_plugin.rs

@@ -1,11 +1,11 @@
+use std::path::{Component, PathBuf};
 use std::sync::LazyLock;
 use std::{borrow::Cow, path::Path};
 
 use cow_utils::CowUtils;
 use derivative::Derivative;
 use futures::future::{join_all, BoxFuture};
 use itertools::Itertools;
-use pathdiff::diff_paths;
 use rayon::prelude::*;
 use regex::Regex;
 use rspack_core::{
@@ -416,13 +416,23 @@ impl SourceMapDevToolPlugin {
 
           if let Some(current_source_mapping_url_comment) = current_source_mapping_url_comment {
             let source_map_url = if let Some(public_path) = &self.public_path {
-              Cow::Owned(format!("{public_path}{source_map_filename}"))
-            } else if let Some(dirname) = Path::new(filename.as_ref()).parent()
-              && let Some(relative) = diff_paths(&source_map_filename, dirname)
-            {
-              Cow::Owned(relative.to_string_lossy().to_string())
+              format!("{public_path}{source_map_filename}")
             } else {
-              Cow::Borrowed(source_map_filename.as_str())
+              let mut file_path = PathBuf::new();
+              file_path.push(Component::RootDir);
+              file_path.extend(Path::new(filename.as_ref()).components());
+
+              let mut source_map_path = PathBuf::new();
+              source_map_path.push(Component::RootDir);
+              source_map_path.extend(Path::new(&source_map_filename).components());
+
+              relative(
+                #[allow(clippy::unwrap_used)]
+                file_path.parent().unwrap(),
+                &source_map_path,
+              )
+              .to_string_lossy()
+              .to_string()
             };
             let data = data.url(&source_map_url);
             let current_source_mapping_url_comment = match &current_source_mapping_url_comment {

crates/rspack_util/src/path.rs

@@ -1,12 +1,43 @@
-use std::path::{Path, PathBuf};
+use std::path::{Component, Components, Path, PathBuf};
+
+fn normalize(parts: Components, allow_above_root: bool) -> Vec<Component> {
+  let mut res = vec![];
+  for p in parts {
+    match &p {
+      Component::CurDir => (),
+      Component::ParentDir => {
+        if !matches!(
+          res.last(),
+          Some(Component::ParentDir) | Some(Component::RootDir)
+        ) {
+          res.pop();
+        } else if allow_above_root {
+          res.push(p);
+        }
+      }
+      _ => res.push(p),
+    }
+  }
+  res
+}
 
 pub fn relative(from: &Path, to: &Path) -> PathBuf {
   if from == to {
     return PathBuf::new();
   }
 
-  let mut from_iter = from.components();
-  let mut to_iter = to.components();
+  let is_from_absolute = matches!(from.components().next(), Some(Component::RootDir));
+  let is_to_absolute = matches!(to.components().next(), Some(Component::RootDir));
+
+  // At this point the path should be resolved to a full absolute path, but
+  // handle relative paths to be safe
+
+  // Normalize the path
+  let from = normalize(from.components(), !is_from_absolute);
+  let to = normalize(to.components(), !is_to_absolute);
+
+  let mut from_iter = from.iter();
+  let mut to_iter = to.iter();
   let mut common_parts = 0;
 
   let from_remain = loop {
@@ -24,7 +55,7 @@ pub fn relative(from: &Path, to: &Path) -> PathBuf {
     result.push("..");
   }
 
-  let to_iter = to.components().skip(common_parts);
+  let to_iter = to.into_iter().skip(common_parts);
   for part in to_iter {
     result.push(part.as_os_str());
   }
@@ -59,6 +90,8 @@ mod test {
       ("/baz-quux", "/baz", "../baz"),
       ("/baz", "/baz-quux", "../baz-quux"),
       ("/page1/page2/foo", "/", "../../.."),
+      // Fix https://github.com/web-infra-dev/rspack/issues/8219
+      ("/", "/../maps/main.js.map", "maps/main.js.map"),
     ];
 
     for (from, to, expected) in test_cases {

packages/rspack-test-tools/tests/configCases/output/source-map-filename/index.js

@@ -1,8 +1,12 @@
-import fs from "fs";
+import fs from "fs/promises";
 import path from "path";
+
 it("source-map-filename/name should same", async function () {
 	import("./two");
-	expect(
-		fs.readdirSync(path.resolve(__dirname, "")).includes("main.js.map")
-	).toBe(true);
+
+	expect(async () => await fs.stat(path.resolve(__dirname, "../maps/main.js.map"))).not.toThrow();
+
+	const outputCode = await fs.readFile(__filename, 'utf-8');
+	const sourceMapPath = outputCode.match(/\/\/# sourceMappingURL=(.*)/)?.[1];
+	expect(sourceMapPath).toBe(path.normalize("maps/main.js.map"));
 });

packages/rspack-test-tools/tests/configCases/output/source-map-filename/rspack.config.js

@@ -7,6 +7,6 @@ module.exports = {
 	target: "node",
 	output: {
 		filename: "[name].js",
-		sourceMapFilename: "[name].js.map"
+		sourceMapFilename: "../maps/[name].js.map"
 	}
 };