source common.sh

$NIX_BIN_DIR/nix-collect-garbage -vvvvv

drvPath1=$($nixinstantiate gc-concurrent.nix)
outPath1=$($nixstore -q $drvPath1)

drvPath2=$($nixinstantiate gc-concurrent2.nix)
outPath2=$($nixstore -q $drvPath2)

rm -f "$NIX_STATE_DIR"/gcroots/foo
ln -s $drvPath2 "$NIX_STATE_DIR"/gcroots/foo

# Start build #1 in the background.  It starts immediately.
$nixstore -rvv "$drvPath1" &
pid1=$!

# Start build #2 in the background after 6 seconds.
(sleep 6 && $nixstore -rvv "$drvPath2") &
pid2=$!

# Run the garbage collector while the build is running.
sleep 4
$NIX_BIN_DIR/nix-collect-garbage -vvvvv

# Wait for build #1/#2 to finish.
echo waiting for pid $pid1 to finish...
wait $pid1
echo waiting for pid $pid2 to finish...
wait $pid2

# Check that the root of build #1 and its dependencies haven't been
# deleted.  The should not be deleted by the GC because they were
# being built during the GC.
cat $outPath1/foobar
cat $outPath1/input-2/bar

# Check that build #2 has succeeded.  It should succeed because the
# derivation is a GC root.
cat $outPath2/foobar

rm "$NIX_STATE_DIR"/gcroots/foo