feat(es/module): Improve error message about relative jsc.baseUrl (#…

…7827)

crates/swc_ecma_transforms_module/src/path.rs

@@ -103,8 +103,14 @@ where
         if let Some(base_dir) = &base_dir {
             assert!(
                 base_dir.is_absolute(),
-                "base_dir({}) must be absolute. Please ensure that `jsc.baseUrl` is specified \
-                 correctly.",
+                "base_dir(`{}`) must be absolute. Please ensure that `jsc.baseUrl` is specified \
+                 correctly. This cannot be deduced by SWC itself because SWC is a transpiler and \
+                 it does not try to resolve project details. In other works, SWC does not know \
+                 which directory should be used as a base directory. It can be deduced if \
+                 `.swcrc` is used, but if not, there are many candidates. e.g. the directory \
+                 containing `package.json`, or the current working directory. Because of that, \
+                 the caller (typically the developer of the JavaScript package) should specify \
+                 it. If you see this error, please report an issue to the package author.",
                 base_dir.display()
             );
         }