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Merge pull request #1561 from hasufell/PR/cabal-freeze-files
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* Add `index-state` to `cabal.project` to help make builds reproducible
* sh script to regenerate it
jneira authored Jan 10, 2020
2 parents 059f354 + f2881f2 commit 92ac896
Showing 2 changed files with 68 additions and 0 deletions.
2 changes: 2 additions & 0 deletions cabal.project
Original file line number Diff line number Diff line change
@@ -15,3 +15,5 @@ constraints:
hie-plugin-api +pedantic

write-ghc-environment-files: never

index-state: 2020-01-07T22:09:46Z
66 changes: 66 additions & 0 deletions update-index-state.sh
Original file line number Diff line number Diff line change
@@ -0,0 +1,66 @@
#!/usr/bin/env bash

set -eu

status_message() {
printf "\\033[0;32m%s\\033[0m\\n" "$1"
}

error_message() {
printf "\\033[0;31m%s\\033[0m\\n" "$1"
}

SCRIPTPATH="$( cd "$(dirname "$0")" ; pwd -P )"
CACHE_LOCATION="${HOME}/.cabal/packages/hackage.haskell.org/01-index.cache"

if [ ! -f "${CACHE_LOCATION}" ] ; then
error_message "${CACHE_LOCATION} does not exist, did you run 'cabal update'?"
exit 1
fi

if [ ! -f "${SCRIPTPATH}/cabal.project" ] ; then
error_message "Could not find ${SCRIPTPATH}/cabal.project, skipping index state update."
exit 3
fi

cabal v2-update

arch=$(getconf LONG_BIT)

case "${arch}" in
32)
byte_size=4
magic_word="CABA1002"
;;
64)
byte_size=8
magic_word="00000000CABA1002"
;;
*)
error_message "Unknown architecture (long bit): ${arch}"
exit 2
;;
esac

# This is the logic to parse the binary format of 01-index.cache.
# The first word is a magic 'caba1002', the second one is the timestamp in unix epoch.
# Better than copying the cabal-install source code.
if [ "$(xxd -u -p -l${byte_size} -s 0 "${CACHE_LOCATION}")" != "${magic_word}" ] ; then
error_message "Magic word does not match!"
exit 4
fi
cache_timestamp=$(echo "ibase=16;obase=A;$(xxd -u -p -l${byte_size} -s ${byte_size} "${CACHE_LOCATION}")" | bc)

# If we got junk from the binary file, this should fail.
cache_date=$(date --utc --date "@${cache_timestamp}" "+%FT%TZ")


status_message "Updating index state in ${SCRIPTPATH}/cabal.project"

if grep -q "^index-state: .*" "${SCRIPTPATH}/cabal.project" ; then
awk '/index-state:/ {gsub(/.*/, "index-state: '${cache_date}'")}; { print }' "${SCRIPTPATH}/cabal.project" > "${SCRIPTPATH}/cabal.project.tmp"
mv "${SCRIPTPATH}/cabal.project.tmp" "${SCRIPTPATH}/cabal.project"
else
printf "index-state: %s\n" "${cache_date}" >> "${SCRIPTPATH}/cabal.project"
fi

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