feat: add hint for missing resolve.extensions when resolving module (#…

…5680)

* feat: add resolve extension fail hint

* chore: update resolve message

* refactor: give a hint when the relative paths aren't resolved

* chore: update test case

* fix: comment

* fix: clippy warning

* fix: clippy

crates/rspack_core/src/resolver/mod.rs

@@ -1,6 +1,7 @@
 mod factory;
 mod resolver_impl;
-
+use std::borrow::Borrow;
+use std::fs;
 use std::{fmt, path::PathBuf};
 
 use once_cell::sync::Lazy;
@@ -169,6 +170,101 @@ which tries to resolve these kind of requests in the current directory too.",
     }
   }
 
+  // try to resolve relative path with extension
+  if RELATIVE_PATH_REGEX.is_match(args.specifier) {
+    let connected_path = base_dir.join(args.specifier);
+    let normalized_path = connected_path.absolutize();
+
+    let mut is_resolving_dir = false; // whether the request is to resolve a directory or not
+
+    let file_name = normalized_path.file_name();
+    let parent_path = match fs::metadata(&normalized_path) {
+      Ok(metadata) => {
+        // if the path is not directory, we need to resolve the parent directory
+        if !metadata.is_dir() {
+          normalized_path.parent()
+        } else {
+          is_resolving_dir = true;
+          Some(normalized_path.borrow())
+        }
+      }
+      Err(_) => normalized_path.parent(),
+    };
+
+    if file_name.is_some() && parent_path.is_some() {
+      let file_name = file_name.expect("fail to get the filename of the current resolved module");
+      let parent_path =
+        parent_path.expect("fail to get the parent path of the current resolved module");
+
+      // read the files in the parent directory
+      let files = fs::read_dir(parent_path);
+      match files {
+        Ok(files) => {
+          let mut requested_names = vec![file_name
+            .to_str()
+            .map(|f| f.to_string())
+            .unwrap_or_default()];
+          if is_resolving_dir {
+            // The request maybe is like `./` or `./dir` to resolve the main file (e.g.: index) in directory
+            // So we need to check them.
+            let main_files = dep
+              .resolve_options
+              .as_deref()
+              .or(Some(&plugin_driver.options.resolve))
+              .and_then(|o| o.main_files.as_ref().cloned())
+              .unwrap_or_default();
+
+            requested_names.extend(main_files);
+          }
+
+          let suggestions = files
+            .into_iter()
+            .filter_map(|file| {
+              file.ok().and_then(|file| {
+                file.path().file_stem().and_then(|file_stem| {
+                  if requested_names.contains(&file_stem.to_string_lossy().to_string()) {
+                    let mut suggestion = file.path().relative(args.context.as_path());
+
+                    if !suggestion.to_string_lossy().starts_with('.') {
+                      suggestion = PathBuf::from(format!("./{}", suggestion.to_string_lossy()));
+                    }
+                    Some(suggestion)
+                  } else {
+                    None
+                  }
+                })
+              })
+            })
+            .collect::<Vec<_>>();
+
+          if suggestions.is_empty() {
+            return None;
+          }
+
+          let mut hint: Vec<String> = vec![];
+          for suggestion in suggestions {
+            let suggestion_ext = suggestion
+              .extension()
+              .map(|e| e.to_string_lossy())
+              .unwrap_or_default();
+            let suggestion_path = suggestion.to_string_lossy();
+            let specifier = args.specifier;
+
+            hint.push(format!(
+          "Found the module '{suggestion_path}' exists, but its extension is not listed in the `resolve.extensions`. Here are some possible solutions:
+
+1. add the extension `\".{suggestion_ext}\"` to `resolve.extensions` in your rspack configuration
+2. use '{suggestion_path}' instead of '{specifier}'
+"));
+          }
+
+          return Some(hint.join("\n"));
+        }
+        Err(_) => return None,
+      }
+    }
+  }
+
   None
 }
 

packages/rspack/tests/diagnostics/builtins/recoverable_syntax_error/stats.err

@@ -1 +1,5 @@
 ERROR in × Resolve error: Can't resolve './' in '<PROJECT_ROOT>/tests/diagnostics/builtins/recoverable_syntax_error'
+  help: Found the module './index.tsx' exists, but its extension is not listed in the `resolve.extensions`. Here are some possible solutions:
+
+        1. add the extension `".tsx"` to `resolve.extensions` in your rspack configuration
+        2. use './index.tsx' instead of './'

packages/rspack/tests/diagnostics/factorize/resolve-extensions-error/err/index.js

@@ -0,0 +1 @@
+import a from '../a';

packages/rspack/tests/diagnostics/factorize/resolve-extensions-error/index.js

@@ -0,0 +1,3 @@
+import './err';
+import './test';
+import a from './a';

packages/rspack/tests/diagnostics/factorize/resolve-extensions-error/stats.err

@@ -0,0 +1,36 @@
+ERROR in ./err/index.js
+  × Resolve error: Can't resolve '../a' in '<PROJECT_ROOT>/tests/diagnostics/factorize/resolve-extensions-error/err'
+   ╭────
+ 1 │ import a from '../a';
+   ·               ──────
+   ╰────
+  help: Found the module '../a.txt' exists, but its extension is not listed in the `resolve.extensions`. Here are some possible solutions:
+
+        1. add the extension `".txt"` to `resolve.extensions` in your rspack configuration
+        2. use '../a.txt' instead of '../a'
+
+ERROR in ./index.js
+  × Resolve error: Can't resolve './test' in '<PROJECT_ROOT>/tests/diagnostics/factorize/resolve-extensions-error'
+   ╭─[1:1]
+ 1 │ import './err';
+ 2 │ import './test';
+   ·        ────────
+ 3 │ import a from './a';
+   ╰────
+  help: Found the module './test/index.txt' exists, but its extension is not listed in the `resolve.extensions`. Here are some possible solutions:
+
+        1. add the extension `".txt"` to `resolve.extensions` in your rspack configuration
+        2. use './test/index.txt' instead of './test'
+
+ERROR in ./index.js
+  × Resolve error: Can't resolve './a' in '<PROJECT_ROOT>/tests/diagnostics/factorize/resolve-extensions-error'
+   ╭─[1:1]
+ 1 │ import './err';
+ 2 │ import './test';
+ 3 │ import a from './a';
+   ·               ─────
+   ╰────
+  help: Found the module './a.txt' exists, but its extension is not listed in the `resolve.extensions`. Here are some possible solutions:
+
+        1. add the extension `".txt"` to `resolve.extensions` in your rspack configuration
+        2. use './a.txt' instead of './a'

packages/rspack/tests/diagnostics/factorize/resolve-extensions-error/webpack.config.js

@@ -0,0 +1,2 @@
+module.exports = {
+}