2 files changed, 12 insertions, 0 deletions
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index 7caee1da7..3f6d4c0c9 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -205,6 +205,16 @@ Hash::Hash(const std::string & s, HashType type)
         throw BadHash("hash '%s' has wrong length for hash type '%s'", s, printHashType(type));
 }
 
+Hash newHashAllowEmpty(std::string hashStr, HashType ht)
+{
+    if (hashStr.empty())
+    {
+        Hash h(ht);
+        warn("found empty hash, assuming you wanted '%s'", h.to_string(SRI));
+    } else
+        return Hash(hashStr, ht);
+}
+
 
 union Ctx
 {
diff --git a/src/libutil/hash.hh b/src/libutil/hash.hh
index 4ff13f6b2..5080539b2 100644
--- a/src/libutil/hash.hh
+++ b/src/libutil/hash.hh
@@ -94,6 +94,8 @@ struct Hash
     }
 };
 
+/* Helper that defaults empty hashes to the 0 hash. */
+Hash newHashAllowEmpty(std::string hashStr, HashType ht);
 
 /* Print a hash in base-16 if it's MD5, or base-32 otherwise. */
 string printHash16or32(const Hash & hash);