From ddaf2750b5af28d56b99f79d3ac20ae11d3464d3 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 9 May 2023 10:22:38 -0400
Subject: [PATCH] Specialize more methods, fix tests

---
 src/libstore/local-overlay-store.cc | 30 +++++++++++++++++++++++++----
 src/libstore/local-overlay-store.hh |  2 ++
 src/libstore/local-store.hh         |  2 +-
 tests/overlay-local-store/inner.sh  | 26 ++++++++++++-------------
 4 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/src/libstore/local-overlay-store.cc b/src/libstore/local-overlay-store.cc
index a98d2e8fd..ad1947698 100644
--- a/src/libstore/local-overlay-store.cc
+++ b/src/libstore/local-overlay-store.cc
@@ -4,9 +4,7 @@
 namespace nix {
 
 Path LocalOverlayStoreConfig::toUpperPath(const StorePath & path) {
-    auto res = upperLayer + "/" + path.to_string();
-    warn("upper path: %s", res);
-    return res;
+    return upperLayer + "/" + path.to_string();
 }
 
 LocalOverlayStore::LocalOverlayStore(const Params & params)
@@ -91,7 +89,31 @@ bool LocalOverlayStore::isValidPathUncached(const StorePath & path)
 {
     auto res = LocalStore::isValidPathUncached(path);
     if (res) return res;
-    return lowerStore->isValidPath(path);
+    res = lowerStore->isValidPath(path);
+    if (res) {
+        // Get path info from lower store so upper DB genuinely has it.
+        LocalStore::registerValidPath(*lowerStore->queryPathInfo(path));
+    }
+    return res;
+}
+
+
+void LocalOverlayStore::registerValidPaths(const ValidPathInfos & infos)
+{
+    // First, get any from lower store so we merge
+    {
+        StorePathSet notInUpper;
+        for (auto & [p, _] : infos)
+            if (!LocalStore::isValidPathUncached(p)) // avoid divergence
+                notInUpper.insert(p);
+        auto pathsInLower = lowerStore->queryValidPaths(notInUpper);
+        ValidPathInfos inLower;
+        for (auto & p : pathsInLower)
+            inLower.insert_or_assign(p, *lowerStore->queryPathInfo(p));
+        LocalStore::registerValidPaths(inLower);
+    }
+    // Then do original request
+    LocalStore::registerValidPaths(infos);
 }
 
 
diff --git a/src/libstore/local-overlay-store.hh b/src/libstore/local-overlay-store.hh
index c087b3893..daebe8547 100644
--- a/src/libstore/local-overlay-store.hh
+++ b/src/libstore/local-overlay-store.hh
@@ -89,6 +89,8 @@ private:
 
     bool isValidPathUncached(const StorePath & path) override;
 
+    void registerValidPaths(const ValidPathInfos & infos) override;
+
     void addToStore(const ValidPathInfo & info, Source & source,
         RepairFlag repair, CheckSigsFlag checkSigs) override;
 
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 55add18dd..b61ec3590 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -232,7 +232,7 @@ public:
      */
     void registerValidPath(const ValidPathInfo & info);
 
-    void registerValidPaths(const ValidPathInfos & infos);
+    virtual void registerValidPaths(const ValidPathInfos & infos);
 
     unsigned int getProtocol() override;
 
diff --git a/tests/overlay-local-store/inner.sh b/tests/overlay-local-store/inner.sh
index d9d3b76cf..dc8ec8c2c 100755
--- a/tests/overlay-local-store/inner.sh
+++ b/tests/overlay-local-store/inner.sh
@@ -22,7 +22,7 @@ mkdir -p "$TEST_ROOT"/{store-a,store-b,merged-store/nix/store,workdir}
 nix-store --store "$storeA" --add dummy
 
 # Build something in lower store
-path=$(nix-build ./hermetic.nix --arg busybox "$busybox" --arg seed 1 --store "$storeA")
+path=$(nix-build ./hermetic.nix --arg busybox "$busybox" --arg seed 1 --store "$storeA" --no-out-link)
 
 mount -t overlay overlay \
   -o lowerdir="$storeA/nix/store" \
@@ -73,17 +73,15 @@ stat $(toRealPath "$storeA/nix/store" "$path")
 # upper layer should still not have it (no redundant copy)
 expect 1 stat $(toRealPath "$storeB/nix/store" "$path")
 
-## Ooops something went wrong
+### Do a build in overlay store
 
-## ### Do a build in overlay store
-##
-## path=$(nix-build ./hermetic.nix --arg busybox $busybox --arg seed 2 --store "$storeB")
-##
-## # Checking for path in lower layer (should fail)
-## expect 1 stat $(toRealPath "$storeA/nix/store" "$path")
-##
-## # Checking for path in upper layer
-## stat $(toRealPath "$storeBTop" "$path")
-##
-## # Verifying path in overlay store
-## nix-store --verify-path --store "$storeB" "$path"
+path=$(nix-build ./hermetic.nix --arg busybox $busybox --arg seed 2 --store "$storeB" --no-out-link)
+
+# Checking for path in lower layer (should fail)
+expect 1 stat $(toRealPath "$storeA/nix/store" "$path")
+
+# Checking for path in upper layer
+stat $(toRealPath "$storeBTop" "$path")
+
+# Verifying path in overlay store
+nix-store --verify-path --store "$storeB" "$path"