Pull request overview

This PR implements automatic fallback to the default branch when the LLM passes "main" as the ref parameter to get_file_contents and that branch doesn't exist. The change helps avoid unnecessary failures and reduces round-trips to the LLM by auto-resolving to the repository's default branch. A note is added to the success message to inform the user that the ref was changed.

Key changes:

• Added resolveDefaultBranch helper function to fetch the repository's default branch reference
• Modified resolveGitReference to fallback to the default branch when "main" doesn't exist
• Updated success messages in GetFileContents to include a note when fallback occurs

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

Great improvement! I love the idea of falling back to the default branch when main doesn't exist.

The only concern I have here is about maintainability. Specifically, here:

if !strings.HasSuffix(rawOpts.Ref, originalRef) {
	successNote = fmt.Sprintf(" Note: the provided ref '%s' does not exist, default branch '%s' was used instead.", originalRef, rawOpts.Ref)
}

We are assuming that if !strings.HasSuffix(rawOpts.Ref, originalRef) is true then it must be due to the fact that we used the fallback logic. This might work today because we know the only case where the resolved ref wouldn't end with the original ref is the fallback, but it introduces implicit coupling: for example, if we ever change resolveGitReference to transform refs in other ways (e.g. lowercasing) the suffix check could fail even when no fallback was used.

And I think we might run into weird edge cases too with the current logic: for example if a user passes main and the default branch is something-main the fallback would be used, but no note would be generated even though a fallback occurred.

Given this I wonder if we should make the logic here more explicit. For example the resolveGitReference function could return an explicit signal when a fallback has been used. That way we could do an explicit check like if result.FallbackOccurred or if result.FallbackRef != "" rather than inferring the fallback from the string comparisons.

What do you think?

🚀