Add Hash::dummy to signal default value

We did this in the same spirit of the dummy value that's present in
libstore/path.hh

2 files changed, 4 insertions, 0 deletions

diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index dfb3668f1..4a94f0dfd 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -136,6 +136,8 @@ std::string Hash::to_string(Base base, bool includeType) const
     return s;
 }
 
+Hash Hash::dummy(htSHA256);
+
 Hash Hash::parseSRI(std::string_view original) {
     auto rest = original;
 
diff --git a/src/libutil/hash.hh b/src/libutil/hash.hh
index 00ce7bb6f..0520c6022 100644
--- a/src/libutil/hash.hh
+++ b/src/libutil/hash.hh
@@ -105,6 +105,8 @@ public:
         assert(type == htSHA1);
         return std::string(to_string(Base16, false), 0, 7);
     }
+
+    static Hash dummy;
 };
 
 /* Helper that defaults empty hashes to the 0 hash. */