Method resolve

src/managers/GitRefManager.js:259–314

* Resolves a ref to its object ID. * * @param {Object} args * @param {FSClient} args.fs - A file system implementation. * @param {string} [args.gitdir] - [required] The [git directory](dir-vs-gitdir.md) path * @param {string} args.ref - The ref to resolve. * @param {number} [args.d

({
    fs,
    gitdir,
    ref,
    depth = undefined,
    visited = new Set(),
  })

   * @returns {Promise<string>} - The resolved object ID.
   */
  static async resolve({
    fs,
    gitdir,
    ref,
    depth = undefined,
    visited = new Set(),
  }) {
    if (depth !== undefined) {
      depth--
      if (depth === -1) {
        return ref
      }
    }

    // Is it a ref pointer?
    if (ref.startsWith('ref: ')) {
      ref = ref.slice('ref: '.length)
      return GitRefManager.resolve({ fs, gitdir, ref, depth, visited })
    }
    // Is it a complete and valid SHA?
    if (ref.length === 40 && /[0-9a-f]{40}/.test(ref)) {
      return ref
    }
    // We need to alternate between the file system and the packed-refs
    const packedMap = await GitRefManager.packedRefs({ fs, gitdir })
    // Look in all the proper paths, in this order
    const allpaths = refpaths(ref).filter(p => !GIT_FILES.includes(p)) // exclude git system files (#709)

    for (const ref of allpaths) {
      const sha = await acquireLock(
        ref,
        async () =>
          (await fs.read(`${gitdir}/${ref}`, { encoding: 'utf8' })) ||
          packedMap.get(ref)
      )
      if (sha) {
        // Guard against circular symbolic references (e.g. a -> b -> a). Without
        // tracking visited refs this recursion would not terminate.
        if (visited.has(ref)) {
          throw new InternalError(
            `Circular reference detected while resolving ref "${ref}"`
          )
        }
        visited.add(ref)
        return GitRefManager.resolve({
          fs,
          gitdir,
          ref: sha.trim(),
          depth,
          visited,
        })
      }
    }
    // Do we give up?
    throw new NotFoundError(ref)
  }

  /**