Fix bug, test more, document more

1 files changed, 5 insertions, 1 deletions

diff --git a/src/libstore/derived-path.cc b/src/libstore/derived-path.cc
index 11a3f5e23..f6a0c01df 100644
--- a/src/libstore/derived-path.cc
+++ b/src/libstore/derived-path.cc
@@ -97,8 +97,12 @@ DerivedPath::Built DerivedPath::Built::parse(const Store & store, std::string_vi
 {
     auto drvPath = store.parseStorePath(drvS);
     std::set<std::string> outputs;
-    if (outputsS != "*")
+    if (outputsS != "*") {
         outputs = tokenizeString<std::set<std::string>>(outputsS, ",");
+        if (outputs.empty())
+            throw Error(
+                 "Explicit list of wanted outputs '%s' must not be empty. Consider using '*' as a wildcard meaning all outputs if no output in particular is wanted.", outputsS);
+	}
     return {drvPath, outputs};
 }