From 480c2b6699e6afc6a746ba8a72319f197c3556ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophane=20Hufschmitt?=
 <theophane.hufschmitt@tweag.io>
Date: Wed, 8 Jun 2022 15:13:11 +0200
Subject: [PATCH] Rewrite the CA paths when moving them between store

Bring back the possibility to copy CA paths with no reference (like the
outputs of FO derivations or stuff imported at eval time) between stores
that have a different prefix.
---
 src/libstore/store-api.cc | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index eeec6c6f7..61a12e84a 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -289,18 +289,6 @@ void Store::addMultipleToStore(
 
         [&](const StorePath & path) {
             auto & [info, source] = *infosMap.at(path);
-            /* auto storePathForDst = info.storePath; */
-            /* if (info->ca && info->references.empty()) { */
-            /*     storePathForDst = dstStore.makeFixedOutputPathFromCA(storePath.name(), *info->ca); */
-            /*     if (dstStore.storeDir == srcStore.storeDir) */
-            /*         assert(storePathForDst == storePath); */
-            /*     if (storePathForDst != storePath) */
-            /*         debug("replaced path '%s' to '%s' for substituter '%s'", */
-            /*             srcStore.printStorePath(storePath), */
-            /*             dstStore.printStorePath(storePathForDst), */
-            /*             dstStore.getUri()); */
-            /* } */
-            /* pathsMap.insert_or_assign(storePath, storePathForDst); */
 
             if (isValidPath(info.path)) {
                 nrDone++;
@@ -1085,10 +1073,32 @@ std::map<StorePath, StorePath> copyPaths(
 
     Store::PathsSource pathsToCopy;
 
+    auto computeStorePathForDst = [&](const ValidPathInfo & currentPathInfo) -> StorePath {
+        auto storePathForSrc = currentPathInfo.path;
+        auto storePathForDst = storePathForSrc;
+        if (currentPathInfo.ca && currentPathInfo.references.empty()) {
+            storePathForDst = dstStore.makeFixedOutputPathFromCA(storePathForSrc.name(), *currentPathInfo.ca);
+            if (dstStore.storeDir == srcStore.storeDir)
+                assert(storePathForDst == storePathForSrc);
+            if (storePathForDst != storePathForSrc)
+                debug("replaced path '%s' to '%s' for substituter '%s'",
+                        srcStore.printStorePath(storePathForSrc),
+                        dstStore.printStorePath(storePathForDst),
+                        dstStore.getUri());
+        }
+        return storePathForDst;
+    };
+
     for (auto & missingPath : sortedMissing) {
         auto info = srcStore.queryPathInfo(missingPath);
-        auto source = sinkToSource([&](Sink & sink) {
 
+        auto storePathForDst = computeStorePathForDst(*info);
+        pathsMap.insert_or_assign(missingPath, storePathForDst);
+
+        ValidPathInfo infoForDst = *info;
+        infoForDst.path = storePathForDst;
+
+        auto source = sinkToSource([&](Sink & sink) {
             // We can reasonably assume that the copy will happen whenever we
             // read the path, so log something about that at that point
             auto srcUri = srcStore.getUri();
@@ -1101,7 +1111,7 @@ std::map<StorePath, StorePath> copyPaths(
 
             srcStore.narFromPath(missingPath, sink);
         });
-        pathsToCopy.push_back(std::pair{*info, std::move(source)});
+        pathsToCopy.push_back(std::pair{infoForDst, std::move(source)});
     }
 
     dstStore.addMultipleToStore(pathsToCopy, act, repair, checkSigs);