Function readFileAtRef

packages/bumpy/src/core/git.ts:155–157

(rootDir: string, ref: string, path: string)

 * Returns null if the file does not exist at that ref.
 */
export function readFileAtRef(rootDir: string, ref: string, path: string): string | null {
  return tryRunArgs(['git', 'show', `${ref}:${path}`], { cwd: rootDir });
}

/** Get commits on the current branch since it diverged from baseBranch */
export function getBranchCommits(