support .tar, .gz, and .zip chart imports

[ritesh-karankal]

Description

This PR fixes #748

Notes for Reviewers

• ParseFileAsHelmChart() previously attempted to load .gz, .zip, .tar, and similar archive types using loader.LoadArchive() on raw bytes. However, this approach failed for several reasons:

  • These archives often extract into a folder with the chart inside a nested directory (e.g., my-chart/Chart.yaml), which LoadArchive() cannot handle.

  • LoadArchive() expects a .tgz archive with a flat, Helm-native layout — not arbitrary .zip or .tar structures.

  • It does not support directories (ExtractedContentPath) or already-extracted content.

  • .zip files are not tarballs and are not natively supported by Helm’s loader.

This has been fixed by replacing loader.LoadArchive() with loader.Load(), which works with directory paths. It now uses ExtractedContentPath along with a recursive FindChartDir() function to locate and load the Chart.yaml from nested folders after extraction.

• Introduced a new identifyExtension() function that prioritizes longer extensions first (e.g., .tar.gz, .tar.tgz), ensuring format recognition.
• Added cleanup of macOS hidden files and directory name sanitization

Please review the changes and share any feedback or suggestions.

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[gemini-code-assist]

Summary of Changes

Hello @ritesh-karankal, 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!

This pull request significantly enhances the system's ability to import Helm charts by expanding support to include common archive formats like .tar, .gz, and .zip. The changes address limitations with nested chart directories and introduce robust file and directory sanitization for extracted content, improving overall compatibility and reliability of chart imports.

Highlights

• Helm Chart Import Enhancement: I've updated the ParseFileAsHelmChart function to correctly handle Helm charts packaged in .tar, .gz, and .zip archives. Previously, loader.LoadArchive() was used, which struggled with non-.tgz formats and nested chart directories. Now, loader.Load() is used, which works with extracted directory paths.
• Recursive Chart Directory Discovery: I've introduced a new FindChartDir function that recursively searches within an extracted archive's content to locate the actual directory containing Chart.yaml. This ensures that charts nested within subdirectories (e.g., my-chart/Chart.yaml inside an archive) can be successfully identified and loaded.
• Improved File Extension Identification: A new identifyExtension helper function has been added to accurately determine file extensions, prioritizing longer, more specific extensions like .tar.gz or .tar.tgz over shorter ones like .gz. This improves the robustness of file type recognition.
• Extracted Content Sanitization: To improve compatibility and prevent issues, I've added two new functions: SanitizeDirNames to replace spaces in directory names with hyphens, and removeHiddenFiles to delete macOS-specific hidden files (like .DS_Store and ._*) from extracted archive contents. These sanitization steps are applied after archive extraction.

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[gemini-code-assist]

Code Review

This PR does a great job of adding support for various archive formats (.tar, .gz, .zip) for Helm chart imports. The core logic change from loader.LoadArchive to loader.Load, combined with a recursive search for Chart.yaml, is a solid and correct approach to handle various chart archive structures.

The addition of identifyExtension for better file type detection, sanitization of directory names, and removal of hidden macOS files makes the import process more robust and reliable. The code is well-structured, and the error handling has been improved significantly.

I have a couple of suggestions to further enhance code clarity and performance. Overall, this is an excellent contribution.

[gemini-code-assist]

This comment is slightly misleading. errStopWalk is in scope throughout the function. The purpose of this check is to distinguish the sentinel error, which indicates a successful early exit from the walk, from actual filesystem errors that might occur.

Improving the comment will enhance clarity for future maintenance.

Suggested change

	// Move the error check here so errStopWalk is in scope
	// The walk is expected to stop with errStopWalk if a chart is found; any other error is unexpected.

[gemini-code-assist]

The knownExtensions slice is re-initialized on every call to identifyExtension. For better performance and to follow Go best practices, this should be defined once at the package level as a variable.

This avoids repeated memory allocations and makes the list of extensions easier to manage.

For example:

// at package level
var knownExtensions = []string{".tar.gz", ".tar.tgz", ".tgz", ".tar", ".zip", ".gz", ".yml", ".yaml", ".json"}

func identifyExtension(name string) string {
    // ... use knownExtensions here without re-defining it
}