diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index 9682db730..86877dd1a 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -219,7 +219,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, Source & narSource
             }
         }
 
-        upsertFile(std::string(info.path.to_string()) + ".ls", jsonOut.str(), "application/json");
+        upsertFile(std::string(info.path.hashPart()) + ".ls", jsonOut.str(), "application/json");
     }
 
     /* Optionally maintain an index of DWARF debug info files
diff --git a/tests/binary-cache.sh b/tests/binary-cache.sh
index b05a7d167..fe4ddec8d 100644
--- a/tests/binary-cache.sh
+++ b/tests/binary-cache.sh
@@ -219,7 +219,7 @@ outPath=$(nix-build --no-out-link -E '
 nix copy --to file://$cacheDir?write-nar-listing=1 $outPath
 
 diff -u \
-    <(jq -S < $cacheDir/$(basename $outPath).ls) \
+    <(jq -S < $cacheDir/$(basename $outPath | cut -c1-32).ls) \
     <(echo '{"version":1,"root":{"type":"directory","entries":{"bar":{"type":"regular","size":4,"narOffset":232},"link":{"type":"symlink","target":"xyzzy"}}}}' | jq -S)