patch.yaml

name: Apply patches

needs:
  packages:
    - patch

inputs:
  strip-components:
    description: |
      The number of path components to strip while extracting.
    default: 1

  fuzz:
    description: |
      Sets the maximum fuzz factor. This option only applies to context diffs, and causes patch to ignore up to that many lines in looking for places to install a hunk.
    default: 2

  patches:
    description: |
      A list of patches to apply, as a whitespace delimited string.

  series:
    description: |
      A quilt-style patch series file to apply.

pipeline:
  - runs: |
      strip_components=$(cat <<'MELANGE_STRIP_EOF'
      ${{inputs.strip-components}}
      MELANGE_STRIP_EOF
      )
      strip_components=$(printf '%s' "$strip_components" | sed 's/^[[:space:]]*//' | tr -d '\n')

      fuzz=$(cat <<'MELANGE_FUZZ_EOF'
      ${{inputs.fuzz}}
      MELANGE_FUZZ_EOF
      )
      fuzz=$(printf '%s' "$fuzz" | sed 's/^[[:space:]]*//' | tr -d '\n')

      case "$strip_components" in
        ''|*[!0-9]*)
          printf 'ERROR: strip-components must be a non-negative integer, got: %s\n' "$strip_components" >&2
          exit 1
          ;;
      esac
      case "$fuzz" in
        ''|*[!0-9]*)
          printf 'ERROR: fuzz must be a non-negative integer, got: %s\n' "$fuzz" >&2
          exit 1
          ;;
      esac

      series=$(cat <<'MELANGE_SERIES_EOF'
      ${{inputs.series}}
      MELANGE_SERIES_EOF
      )
      series=$(printf '%s' "$series" | sed 's/^[[:space:]]*//' | tr -d '\n')

      # Ensure that the series path doesn't contain shell metacharacters
      case "$series" in
        *"'"*|*'`'*|*'$('*|*'${'*|*';'*|*'|'*|*'&'*|*'>'*|*'<'*)
          printf 'ERROR: series path contains invalid characters\n' >&2
          exit 1
          ;;
      esac

      if [ -z "$series" ]; then
        patches_input=$(cat <<'MELANGE_PATCHES_EOF'
      ${{inputs.patches}}
      MELANGE_PATCHES_EOF
        )
        patches_input=$(printf '%s' "$patches_input" | sed 's/^[[:space:]]*//')
        if [ -n "$patches_input" ]; then
          series=$(mktemp)
          printf '%s\n' "$patches_input" | awk '{ for(i = 1; i <= NF; i++) { print $i; } }' > "$series"
        else
          printf 'ERROR: Neither patches or series was set.\n' >&2
          exit 1
        fi
      else
        # Verify the series file exists
        if [ ! -f "$series" ]; then
          printf 'ERROR: series file does not exist: %s\n' "$series" >&2
          exit 1
        fi
      fi

      grep -v -E '^(#|$)' "$series" | while IFS= read -r patchfile || [ -n "$patchfile" ]; do
        # Ensure that the patchfile path doesn't contain shell metacharacters
        case "$patchfile" in
          *"'"*|*'`'*|*'$('*|*'${'*|*';'*|*'|'*|*'&'*|*'>'*|*'<'*)
            printf 'ERROR: patch file path contains invalid characters: %s\n' "$patchfile" >&2
            exit 1
            ;;
        esac
        printf 'applying patch file %s\n' "$patchfile"
        patch "-p${strip_components}" "--fuzz=${fuzz}" --verbose < "$patchfile"
      done