From 88bd0c25f2f0fda6502653f40e88c6d377bc4617 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Sat, 27 Sep 2025 16:03:43 -0400
Subject: [PATCH] `Store::registerDrvOutput` make pure virtual

It should be the responsibility of implementations that don't implement
it to say so.

See also PR #9799, and issue #5729
---
 src/libstore/dummy-store.cc                        | 5 +++++
 src/libstore/include/nix/store/legacy-ssh-store.hh | 7 ++++++-
 src/libstore/include/nix/store/store-api.hh        | 5 +----
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/libstore/dummy-store.cc b/src/libstore/dummy-store.cc
index 4b485ca66..43c575263 100644
--- a/src/libstore/dummy-store.cc
+++ b/src/libstore/dummy-store.cc
@@ -258,6 +258,11 @@ struct DummyStore : virtual Store
         return path;
     }
 
+    void registerDrvOutput(const Realisation & output) override
+    {
+        unsupported("registerDrvOutput");
+    }
+
     void narFromPath(const StorePath & path, Sink & sink) override
     {
         bool visited = contents.cvisit(path, [&](const auto & kv) {
diff --git a/src/libstore/include/nix/store/legacy-ssh-store.hh b/src/libstore/include/nix/store/legacy-ssh-store.hh
index 75751e2d1..c91f88a84 100644
--- a/src/libstore/include/nix/store/legacy-ssh-store.hh
+++ b/src/libstore/include/nix/store/legacy-ssh-store.hh
@@ -109,7 +109,7 @@ struct LegacySSHStore : public virtual Store
         unsupported("addToStore");
     }
 
-    virtual StorePath addToStoreFromDump(
+    StorePath addToStoreFromDump(
         Source & dump,
         std::string_view name,
         FileSerialisationMethod dumpMethod = FileSerialisationMethod::NixArchive,
@@ -121,6 +121,11 @@ struct LegacySSHStore : public virtual Store
         unsupported("addToStore");
     }
 
+    void registerDrvOutput(const Realisation & output) override
+    {
+        unsupported("registerDrvOutput");
+    }
+
 public:
 
     BuildResult buildDerivation(const StorePath & drvPath, const BasicDerivation & drv, BuildMode buildMode) override;
diff --git a/src/libstore/include/nix/store/store-api.hh b/src/libstore/include/nix/store/store-api.hh
index 6d3f6b8d0..1131ec975 100644
--- a/src/libstore/include/nix/store/store-api.hh
+++ b/src/libstore/include/nix/store/store-api.hh
@@ -598,10 +598,7 @@ public:
      * floating-ca derivations and their dependencies as there's no way to
      * retrieve this information otherwise.
      */
-    virtual void registerDrvOutput(const Realisation & output)
-    {
-        unsupported("registerDrvOutput");
-    }
+    virtual void registerDrvOutput(const Realisation & output) = 0;
 
     virtual void registerDrvOutput(const Realisation & output, CheckSigsFlag checkSigs)
     {