From 0fc68c3c6b0bd204c687ec1063b752765361498d Mon Sep 17 00:00:00 2001
From: Tristan Ross <tristan.ross@midstall.com>
Date: Mon, 10 Feb 2025 23:09:38 -0800
Subject: [PATCH] Add rejectSystemFeatures to derivations

---
 src/libstore/parsed-derivations.cc               | 12 ++++++++++++
 src/libstore/parsed-derivations.hh               |  2 ++
 src/libstore/unix/build/local-derivation-goal.cc |  3 ++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/libstore/parsed-derivations.cc b/src/libstore/parsed-derivations.cc
index d8459d4d71c2..35620a26fe09 100644
--- a/src/libstore/parsed-derivations.cc
+++ b/src/libstore/parsed-derivations.cc
@@ -98,6 +98,15 @@ StringSet ParsedDerivation::getRequiredSystemFeatures() const
     return res;
 }
 
+StringSet ParsedDerivation::getRejectSystemFeatures() const
+{
+    // FIXME: cache this?
+    StringSet res;
+    for (auto & i : getStringsAttr("rejectSystemFeatures").value_or(Strings()))
+        res.insert(i);
+    return res;
+}
+
 bool ParsedDerivation::canBuildLocally(Store & localStore) const
 {
     if (drv.platform != settings.thisSystem.get()
@@ -112,6 +121,9 @@ bool ParsedDerivation::canBuildLocally(Store & localStore) const
     for (auto & feature : getRequiredSystemFeatures())
         if (!localStore.systemFeatures.get().count(feature)) return false;
 
+    for (auto & feature : getRejectSystemFeatures())
+        if (localStore.systemFeatures.get().count(feature)) return false;
+
     return true;
 }
 
diff --git a/src/libstore/parsed-derivations.hh b/src/libstore/parsed-derivations.hh
index 71085a604d4d..187a768632a8 100644
--- a/src/libstore/parsed-derivations.hh
+++ b/src/libstore/parsed-derivations.hh
@@ -33,6 +33,8 @@ public:
 
     StringSet getRequiredSystemFeatures() const;
 
+    StringSet getRejectSystemFeatures() const;
+
     bool canBuildLocally(Store & localStore) const;
 
     bool willBuildLocally(Store & localStore) const;
diff --git a/src/libstore/unix/build/local-derivation-goal.cc b/src/libstore/unix/build/local-derivation-goal.cc
index 06a2f85be848..dfa6be7175d5 100644
--- a/src/libstore/unix/build/local-derivation-goal.cc
+++ b/src/libstore/unix/build/local-derivation-goal.cc
@@ -532,9 +532,10 @@ void LocalDerivationGoal::startBuilder()
 
     /* Right platform? */
     if (!parsedDrv->canBuildLocally(worker.store))
-        throw Error("a '%s' with features {%s} is required to build '%s', but I am a '%s' with features {%s}",
+        throw Error("a '%s' with features {%s} & not {%s} is required to build '%s', but I am a '%s' with features {%s}",
             drv->platform,
             concatStringsSep(", ", parsedDrv->getRequiredSystemFeatures()),
+            concatStringsSep(", ", parsedDrv->getRejectSystemFeatures()),
             worker.store.printStorePath(drvPath),
             settings.thisSystem,
             concatStringsSep<StringSet>(", ", worker.store.systemFeatures));