fix missing src path when reporting pkg can't import

[Young-Flash]

No description provided.

[peter-jerry-ye-code-review]

Suggestions from git diff Output for module.rs

1. Potential Redundant Path Joining:

   self.source_dir
       .join(self.source.as_ref().unwrap_or(&String::new()))
       .join(pkg.rel.fs_full_name())
       .join(MOON_PKG_JSON)
       .display(),

   This snippet appears twice in the diff, suggesting a potential opportunity to refactor for code readability and maintainability. You might consider extracting this common path joining logic into a separate method to avoid repetition.

2. Error Message Clarity:
   The error messages could be more user-friendly by including more context or suggestions for resolving the issue. For example:

   "{}: cannot import internal package `{}` in `{}`. Ensure the package is correctly referenced and exists.",

   This provides a clearer indication of what might be wrong and how to potentially fix it.

3. Potential Null Pointer Dereference:
   The use of unwrap_or(&String::new()) suggests that there might be a scenario where self.source could be None. While unwrap_or provides a default, it might be safer and more idiomatic to use unwrap_or_else with a clearer fallback strategy or to handle the None case more explicitly to avoid potential runtime errors.

   self.source_dir
       .join(self.source.as_ref().unwrap_or_else(|| &String::new()))
       .join(pkg.rel.fs_full_name())
       .join(MOON_PKG_JSON)
       .display(),

These suggestions aim to improve code readability, maintainability, and safety, ensuring that the codebase remains robust and easy to understand.