fix(skill-downloader): handle in-repo directory symlinks natively#78
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albertodebortoli merged 2 commits intoLucaTools:mainfrom Apr 27, 2026
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This commit fixes an issue where the skill downloader fails on symlinked directories (like in twostraws/SwiftUI-Agent-Skill). 1. `GitHubSkillTreeClient` now decodes the `mode` property from the Git Tree API and filters out `120000` (symlink) modes, preventing them from being processed as files and downloaded as raw text strings. 2. `GitRepositorySkillFetcher` now inspects `isSymbolicLinkKey` during enumeration. If a symlink points to a directory, it skips traversing it to prevent crashing on `Data(contentsOf:)` (POSIX Error 21 - Is a directory). Deduplication handles the actual skill scope cleanly.
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Test that GitHubSkillTreeClient excludes tree items with mode "120000" and that GitRepositorySkillFetcher skips directory symlinks during enumeration.
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Thank you so much @peterfriese 🙏🙏🙏 |
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Fixes #77.
Description
When installing a skill that contains a directory symlink in its repository structure (like
twostraws/SwiftUI-Agent-Skillstarting from commited98890), Luca's native downloader would crash withFailed to download skill at path.Root Cause & Changes
This issue occurred in two different code paths depending on the authentication context:
The GitHub API Path (
GitHubSkillTreeClient.swift)type: "blob"andmode: "120000".GitHubTreeItemonly filtered bytype == "blob". Consequently, Luca treated symlinks as regular files. When requested viaraw.githubusercontent.com, GitHub returns the symlink target path as a raw string (e.g.,../../references), corrupting the structure.modeproperty to the decoding struct and explicitly filtered outmode == "120000".The Local Clone Path (
GitRepositorySkillFetcher.swift)FileManager.default.enumeratorcorrectly skips traversing into symlinks that point to directories becauseisDirectoryKeyevaluates tofalsefor the symlink itself.downloadSkillattempted to read the content viaData(contentsOf: fileURL), the underlying POSIX layer automatically resolved the symlink to the target directory. Reading a directory as a data buffer throws POSIX Error 21 (Is a directory), crashing the downloader..isSymbolicLinkKeycheck in the enumerator loop. If the item is a symlink, we resolve it; if the resolved target is a directory, we skip it.(Since
SKILL.mddefines the root of a skill, shared assets referenced via symlink are still caught correctly by the deduplication logic without throwing errors).Testing
lucaand verifying thatluca install twostraws/SwiftUI-Agent-Skillnatively handles the repository structure correctly and successfully symlinks to the active agents cache without requiring the--use-npxflag.