From f54976d77bd144535e9b4844dbdb6bc52eac11fd Mon Sep 17 00:00:00 2001
From: regnat <rg@regnat.ovh>
Date: Fri, 26 Feb 2021 16:34:33 +0100
Subject: [PATCH] Simplify the case where the drv is a purely input-addressed
 one

---
 src/build-remote/build-remote.cc   |  2 +-
 src/libstore/build/entry-points.cc |  2 +-
 src/libstore/derivations.cc        | 11 +++++++++++
 src/libstore/derivations.hh        |  5 +++++
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/build-remote/build-remote.cc b/src/build-remote/build-remote.cc
index 7f3636f6b..736b81542 100644
--- a/src/build-remote/build-remote.cc
+++ b/src/build-remote/build-remote.cc
@@ -283,7 +283,7 @@ connected:
 
         std::set<Realisation> missingRealisations;
         StorePathSet missingPaths;
-        if (settings.isExperimentalFeatureEnabled("ca-derivations")) {
+        if (settings.isExperimentalFeatureEnabled("ca-derivations") && !derivationHasKnownOutputPaths(drv.type())) {
             for (auto & outputName : wantedOutputs) {
                 auto thisOutputHash = outputHashes.at(outputName);
                 auto thisOutputId = DrvOutput{ thisOutputHash, outputName };
diff --git a/src/libstore/build/entry-points.cc b/src/libstore/build/entry-points.cc
index 99b3fa070..3a05a022c 100644
--- a/src/libstore/build/entry-points.cc
+++ b/src/libstore/build/entry-points.cc
@@ -69,7 +69,7 @@ BuildResult Store::buildDerivation(const StorePath & drvPath, const BasicDerivat
                     outputId,
                     Realisation{ outputId, *staticOutput.second}
                     );
-        if (settings.isExperimentalFeatureEnabled("ca-derivations")) {
+        if (settings.isExperimentalFeatureEnabled("ca-derivations") && !derivationHasKnownOutputPaths(drv.type())) {
             auto realisation = this->queryRealisation(outputId);
             if (realisation)
                 result.builtOutputs.insert_or_assign(
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 6d0742b4f..fe98182bb 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -57,6 +57,17 @@ bool derivationIsFixed(DerivationType dt) {
     assert(false);
 }
 
+bool derivationHasKnownOutputPaths(DerivationType dt) {
+    switch (dt) {
+    case DerivationType::InputAddressed: return true;
+    case DerivationType::CAFixed: return true;
+    case DerivationType::CAFloating: return false;
+    case DerivationType::DeferredInputAddressed: return false;
+    };
+    assert(false);
+}
+
+
 bool derivationIsImpure(DerivationType dt) {
     switch (dt) {
     case DerivationType::InputAddressed: return false;
diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh
index 4e5985fab..061d70f69 100644
--- a/src/libstore/derivations.hh
+++ b/src/libstore/derivations.hh
@@ -94,6 +94,11 @@ bool derivationIsFixed(DerivationType);
    derivation is controlled separately. Never true for non-CA derivations. */
 bool derivationIsImpure(DerivationType);
 
+/* Does the derivation knows its own output paths?
+ * Only true when there's no floating-ca derivation involved in the closure.
+ */
+bool derivationHasKnownOutputPaths(DerivationType);
+
 struct BasicDerivation
 {
     DerivationOutputs outputs; /* keyed on symbolic IDs */