t/subtree-hash

   1 #!/usr/bin/env bash
   2
   3 set -eo pipefail
   4
   5 # Usage: subtree-hash ROOT_HASH [SUBDIR ...]
   6
   7 subtree_hash()
   8 {
   9     root_hash="$1"
  10     if test "$#" -eq 1; then
  11         echo $root_hash
  12     else
  13         subdir="$2"
  14         subtree_info="$(git ls-tree "$root_hash" | grep -E "    $subdir\$")" || true
  15         if test "$(echo "$subtree_info" | wc -l)" -ne 1; then
  16             echo "Found more than one matching line in subtree $root_hash" 1>&2
  17             return 1
  18         fi
  19
  20         subtree_hash="$(echo "$subtree_info" | cut -d' ' -f 3 | cut -d$'\t' -f 1)" || true
  21         if test -z "$subtree_hash"; then
  22             echo "Unable to find subtree hash in git output: $subtree_info" 1>&2
  23             return 1
  24         fi
  25
  26         shift 2
  27         subtree_hash "$subtree_hash" "$@"
  28     fi
  29 }
  30
  31 subtree_hash "$@"