async function getChangedFilesFromGit()

in paths-filter/src/main.ts [96:157]
48 lines of code
16 McCabe index (conditional complexity)

async function getChangedFilesFromGit(base: string, head: string, initialFetchDepth: number): Promise<File[]> {
  const defaultBranch = github.context.payload.repository?.default_branch

  const beforeSha =
    github.context.eventName === 'push' ? (github.context.payload as Webhooks.WebhookPayloadPush).before : null

  const currentRef = await git.getCurrentRef()

  head = git.getShortName(head || github.context.ref || currentRef)
  base = git.getShortName(base || defaultBranch)

  if (!head) {
    throw new Error(
      "This action requires 'head' input to be configured, 'ref' to be set in the event payload or branch/tag checked out in current git repository"
    )
  }

  if (!base) {
    throw new Error(
      "This action requires 'base' input to be configured or 'repository.default_branch' to be set in the event payload"
    )
  }

  const isBaseSha = git.isGitSha(base)
  const isBaseSameAsHead = base === head

  // If base is commit SHA we will do comparison against the referenced commit
  // Or if base references same branch it was pushed to, we will do comparison against the previously pushed commit
  if (isBaseSha || isBaseSameAsHead) {
    const baseSha = isBaseSha ? base : beforeSha
    if (!baseSha) {
      core.warning(`'before' field is missing in event payload - changes will be detected from last commit`)
      if (head !== currentRef) {
        core.warning(`Ref ${head} is not checked out - results might be incorrect!`)
      }
      return await git.getChangesInLastCommit()
    }

    // If there is no previously pushed commit,
    // we will do comparison against the default branch or return all as added
    if (baseSha === git.NULL_SHA) {
      if (defaultBranch && base !== defaultBranch) {
        core.info(
          `First push of a branch detected - changes will be detected against the default branch ${defaultBranch}`
        )
        return await git.getChangesSinceMergeBase(defaultBranch, head, initialFetchDepth)
      } else {
        core.info('Initial push detected - all files will be listed as added')
        if (head !== currentRef) {
          core.warning(`Ref ${head} is not checked out - results might be incorrect!`)
        }
        return await git.listAllFilesAsAdded()
      }
    }

    core.info(`Changes will be detected between ${baseSha} and ${head}`)
    return await git.getChanges(baseSha, head)
  }

  core.info(`Changes will be detected between ${base} and ${head}`)
  return await git.getChangesSinceMergeBase(base, head, initialFetchDepth)
}