Test that delete works for duplicate file edge case.

tests/overlay-local-store/delete-inner.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+set -eu -o pipefail
+
+set -x
+
+source common.sh
+
+# Avoid store dir being inside sandbox build-dir
+unset NIX_STORE_DIR
+unset NIX_STATE_DIR
+
+storeDirs
+
+initLowerStore
+
+mountOverlayfs
+
+# Add to overlay before lower to ensure file is duplicated
+upperPath=$(nix-store --store "$storeB" --add delete.sh)
+lowerPath=$(nix-store --store "$storeA" --add delete.sh)
+[[ "$upperPath" = "$lowerPath" ]]
+
+# Check there really are two files with different inodes
+upperInode=$(stat -c %i "$storeBRoot/$upperPath")
+lowerInode=$(stat -c %i "$storeA/$lowerPath")
+[[ "$upperInode" != "$lowerInode" ]]
+
+# Now delete file via the overlay store
+nix-store --store "$storeB" --delete "$upperPath"
+
+# Check there is no longer a file in upper layer
+expect 1 stat "$storeBTop/${upperPath##/nix/store/}"
+
+# Check that overlay file is now the one in lower layer
+upperInode=$(stat -c %i "$storeBRoot/$upperPath")
+lowerInode=$(stat -c %i "$storeA/$lowerPath")
+[[ "$upperInode" = "$lowerInode" ]]

tests/overlay-local-store/delete.sh

@@ -0,0 +1,5 @@
+source common.sh
+
+requireEnvironment
+setupConfig
+execUnshare ./delete-inner.sh

tests/overlay-local-store/local.mk

@@ -6,6 +6,7 @@ overlay-local-store-tests := \
   $(d)/add-lower.sh \
   $(d)/gc.sh \
   $(d)/verify.sh \
-  $(d)/optimise.sh
+  $(d)/optimise.sh \
+  $(d)/delete.sh
 
 install-tests-groups += overlay-local-store