Fix: Improve error message for download failures

[fannheyward]

When downloading rust-analyzer fails, the previous error message displayed to you was generic:
"Download rust-analyzer failed, you can get it from https://github.com/rust-analyzer/rust-analyzer"

This change enhances the error message by including the specific error details from the exception caught during the download process. The new message format is:
"Download rust-analyzer failed: . You can get it from https://github.com/rust-analyzer/rust-analyzer"

This provides you with more actionable information if a download error occurs, helping you diagnose the issue (e.g., network problems, file system permissions).

[gemini-code-assist]

Hello @fannheyward, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

Hello team, gemini-code-assist here to provide a summary of this pull request. This PR, authored by fannheyward, aims to enhance the user experience when the rust-analyzer download fails. Previously, the error message was generic, simply stating that the download failed. This change modifies the error handling in the download process to capture the specific error details from the exception that occurred and include them directly in the error message displayed to the user. This provides much more actionable information, helping users diagnose the root cause of the download failure, such as network issues or permission problems.

Highlights

• Improved Error Messaging: The primary change is to make the error message displayed upon a failed rust-analyzer download more informative by including the specific error details from the underlying exception.

Changelog

• src/index.ts
  • Modified the catch block within the activate function to extract the error message from the caught exception (e).
  • Updated the error message string (msg) to include the specific error message obtained from the exception, using a template literal.

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---

Download fails, a sad sight,
Error message brings the light.
See the cause, clear the way,
Code works fine another day.

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[gemini-code-assist]

Code Review

This pull request significantly improves the error reporting for rust-analyzer download failures by including specific error messages. The approach taken to extract the message from the error object is clear and handles both Error instances and other types of thrown values. This will provide users with more actionable information when troubleshooting download issues. Well done!

Summary of Findings

• Error Message Specificity for Non-Error Objects: The use of String(e) for non-Error instances is a good fallback. However, if e is a plain object without a custom toString() method, String(e) might resolve to "[object Object]", which isn't very informative. While common error sources usually provide better string representations or are Error instances, a more robust (though more verbose) handling could involve checking for a message property even on non-Error objects. This was considered a low-severity point and thus not commented on directly due to review settings, as the current implementation is already a good improvement.
• Clarity of msg variable re-assignment: The variable msg is declared in an outer scope (line 20) and then re-assigned within this catch block. For slightly improved clarity and encapsulation, the full error message string could be constructed and passed directly to window.showErrorMessage without re-assigning the outer msg. This is a minor stylistic observation and considered low-severity, hence not commented on directly due to review settings.

Merge Readiness

The changes in this pull request are a clear improvement to error handling and provide better feedback to the user. No critical, high, or medium severity issues were found in the introduced changes. The code is well-written and achieves its stated goal effectively. While I am not authorized to approve pull requests, based on this review, the changes appear to be in good shape for merging. It's always recommended to have another pair of eyes review and approve before merging.

[fannheyward]

Jules test.