Derivations can output "text-hashed" data

In particular, this means that derivations can output derivations. But
that ramification isn't (yet!) useful as we would want, since there is
no way to have a dependent derivation that is itself a dependent
derivation.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc
index 052936a8b..71fa81546 100644
--- a/src/libstore/misc.cc
+++ b/src/libstore/misc.cc
@@ -111,9 +111,21 @@ void Store::computeFSClosure(const StorePath & startPath,
 std::optional<ContentAddress> getDerivationCA(const BasicDerivation & drv)
 {
     auto out = drv.outputs.find("out");
-    if (out != drv.outputs.end()) {
-        if (auto v = std::get_if<DerivationOutputCAFixed>(&out->second.output))
-            return v->hash;
+    if (out == drv.outputs.end())
+        return std::nullopt;
+    if (auto dof = std::get_if<DerivationOutputCAFixed>(&out->second.output)) {
+        return std::visit(overloaded {
+        	[&](TextInfo ti) -> std::optional<ContentAddress> {
+        		if (!ti.references.empty())
+        			return std::nullopt;
+        		return static_cast<TextHash>(ti);
+			},
+        	[&](FixedOutputInfo fi) -> std::optional<ContentAddress> {
+        		if (fi.references != PathReferences<StorePath> {})
+        			return std::nullopt;
+        		return static_cast<FixedOutputHash>(fi);
+			},
+        }, dof->ca);
     }
     return std::nullopt;
 }