Let build.cc verify the expected hash of a substituter's output

Since SubstitutionGoal::finished() in build.cc computes the hash
anyway, we can prevent the inefficiency of computing the hash twice by
letting the substituter tell Nix about the expected hash, which can
then verify it.

1 files changed, 1 insertions, 0 deletions

diff --git a/tests/substituter.sh b/tests/substituter.sh
index a6bdacfd66f7..885655760e05 100755
--- a/tests/substituter.sh
+++ b/tests/substituter.sh
@@ -29,6 +29,7 @@ if test $1 = "--query"; then
 elif test $1 = "--substitute"; then
     mkdir $2
     echo "Hallo Wereld" > $2/hello
+    echo # no expected hash
 else
     echo "unknown substituter operation"
     exit 1