#!/usr/bin/env bash

# The mcpp a job's steps run, when that is not the released one.

#

# `MCPP_SOURCE_REF` names a branch or tag of mcpp-community/mcpp. Empty, the

# steps run the release `MCPP_VERSION` names, which the step before this one

# fetched into `$MCPP`. Set, this script builds mcpp at that reference with the

# released mcpp and points `$MCPP` at the result, so that a change to the engine

# is measured against this collection before either is released.

#

# A SCRIPT, NOT A STEP COPIED INTO EACH JOB. Two copies drift, and a job that

# installs mcpp without this channel builds manifests written for the engine

# under review with the released engine, which accepts a key it does not know

# and proceeds without the semantics the key asks for.

#

# WHAT THIS SCRIPT WRITES IS NOT EVIDENCE THAT IT TOOK EFFECT. `GITHUB_ENV`

# governs the steps that follow, so the job's next step compares what `$MCPP`

# names and prints with what this script built.

#

# Environment: MCPP (the released mcpp), MCPP_SOURCE_REF, RUNNER_TEMP, GITHUB_ENV.

set -euo pipefail

: "${MCPP:?the released mcpp, which the step before this one fetches}"

: "${GITHUB_ENV:?}"

: "${RUNNER_TEMP:?}"

echo "MCPP_RELEASED=$MCPP" >> "$GITHUB_ENV"

if [ -z "${MCPP_SOURCE_REF:-}" ]; then

echo "MCPP_SOURCE_REF is empty: the steps run the released $("$MCPP" --version | head -1)"

exit 0

fi

# In Git Bash on Windows `RUNNER_TEMP` is a Windows path (`D:\a\_temp`), and the

# binary path this script exports is used by bash in every later step, so the

# directory is spelled in bash's own syntax.

temp="$RUNNER_TEMP"

if command -v cygpath > /dev/null; then temp=$(cygpath -u "$temp"); fi

src="$temp/mcpp-src"

rm -rf "$src"

git clone --quiet --depth 1 --branch "$MCPP_SOURCE_REF" \

https://github.com/mcpp-community/mcpp.git "$src"

echo "READING source: mcpp-community/mcpp $MCPP_SOURCE_REF at $(git -C "$src" rev-parse HEAD)"

# The clone's `.xlings.json` pins the mcpp that builds mcpp in that repository's

# own CI, and the pin does not move with this job's release: a build inside the

# checkout obeys it and installs a version this job did not choose. Removed, the

# released mcpp above builds the source.

rm -f "$src/.xlings.json"

(cd "$src" && "$MCPP" build)

# A fresh clone holds no earlier build, so what remains is this build's product;

# the count is asserted rather than assumed.

built=$(find "$src/target" -type f \( -name mcpp -o -name mcpp.exe \))

count=$(printf '%s\n' "$built" | grep -c . || true)

if [ "$count" != 1 ]; then

echo "::error::expected one mcpp binary from $MCPP_SOURCE_REF, found $count"

printf '%s\n' "$built" | sed 's/^/ /'

exit 1

fi

version=$("$built" --version | head -1)

echo "READING under review: $version at $built"

{

echo "MCPP=$built"

echo "MCPP_UNDER_REVIEW=$built"

echo "MCPP_UNDER_REVIEW_VERSION=$version"

} >> "$GITHUB_ENV"