#!/usr/bin/env bash
#
# Downgrades every one of our dependencies in Cargo.lock to the
# earliest version listed in our Cargo.toml files.  (And then
# re-upgrades a few second-order dependencies that aren't actually
# supported by our first-order dependencies in their oldest versions.)
#
# If running this script causes a build failure that can be fixed by adding a
# exception, go ahead and add the exception. In the long term, we should switch
# to --direct-minimal-versions, which should not require any exceptions, but it
# will take some work to get that to work - see arti#2032.
#
# The purpose of this script is to make sure that we are actually
# compatible with the versions listed in our Cargo.toml files.
# Without testing this, we could wind up with code that built
# successfully with the versions listed in Cargo.lock, while declaring
# support for versions of our dependencies that won't actually work.

set -euo pipefail

: "${CARGO:=cargo}"

$CARGO +nightly update -Z minimal-versions
$CARGO update \
      -p crc32fast \
      -p zeroize_derive:1.3.2 \
      -p filetime \
      -p tap:1.0.0

# The downgraded 'async-fs@2.0.0' lib specifies a dependency of 'futures-lite' 1.2.0,
# but uses `FutureExt::poll()` which wasn't available until 'futures-lite' 1.9.0.
$CARGO update --precise 1.9.0 futures-lite@1.2.0

# The downgraded `async-global-executor@2.4.0` pulls in `event-listener@3.0.0`
# which mistakenly dropped a `RefUnwindSafe` impl which `async-global-executor` wanted.
# We're getting this via `async-std`, which evidently doesn't have minimal-versions CI
# and will now never have it.
$CARGO update --precise 3.1.0 event-listener@3.0.0