pkgs/build-support/setup-hooks/set-source-date-epoch-to-latest.sh

   1 updateSourceDateEpoch() {
   2     local path="$1"
   3     # Avoid passing option-looking directory to find. The example is diffoscope-269:
   4     #   https://salsa.debian.org/reproducible-builds/diffoscope/-/issues/378
   5     [[ $path == -* ]] && path="./$path"
   6
   7     # Get the last modification time of all regular files, sort them,
   8     # and get the most recent. Maybe we should use
   9     # https://github.com/0-wiz-0/findnewest here.
  10     local -a res=($(find "$path" -type f -not -newer "$NIX_BUILD_TOP/.." -printf '%T@ %p\0' \
  11                     | sort -n --zero-terminated | tail -n1 --zero-terminated | head -c -1))
  12     local time="${res[0]//\.[0-9]*/}" # remove the fraction part
  13     local newestFile="${res[1]}"
  14
  15     # Update $SOURCE_DATE_EPOCH if the most recent file we found is newer.
  16     if [ "${time:-0}" -gt "$SOURCE_DATE_EPOCH" ]; then
  17         echo "setting SOURCE_DATE_EPOCH to timestamp $time of file $newestFile"
  18         export SOURCE_DATE_EPOCH="$time"
  19
  20         # Warn if the new timestamp is too close to the present. This
  21         # may indicate that we were being applied to a file generated
  22         # during the build, or that an unpacker didn't restore
  23         # timestamps properly.
  24         local now="$(date +%s)"
  25         if [ "$time" -gt $((now - 60)) ]; then
  26             echo "warning: file $newestFile may be generated; SOURCE_DATE_EPOCH may be non-deterministic"
  27         fi
  28     fi
  29 }
  30
  31 postUnpackHooks+=(_updateSourceDateEpochFromSourceRoot)
  32
  33 _updateSourceDateEpochFromSourceRoot() {
  34     if [ -n "$sourceRoot" ]; then
  35         updateSourceDateEpoch "$sourceRoot"
  36     fi
  37 }