From a04a5de8f70e5c34be0f0f7ea3c6f2cd50d56982 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Mon, 14 Feb 2005 14:16:56 +0000
Subject: [PATCH] * Implement the `gc-keep-derivations' global configuretion
 flag.

---
 src/libstore/gc.cc | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index 98b863314..e0de6a968 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -306,7 +306,10 @@ void collectGarbage(GCAction action, PathSet & result)
 {
     result.clear();
 
-    bool gcKeepOutputs = queryBoolSetting("gc-keep-outputs", false);
+    bool gcKeepOutputs =
+        queryBoolSetting("gc-keep-outputs", false);
+    bool gcKeepDerivations =
+        queryBoolSetting("gc-keep-derivations", true);
 
     /* Acquire the global GC root.  This prevents
        a) New roots from being added.
@@ -330,6 +333,16 @@ void collectGarbage(GCAction action, PathSet & result)
     for (PathSet::const_iterator i = roots.begin(); i != roots.end(); ++i)
         computeFSClosure(canonPath(*i), livePaths);
 
+    if (gcKeepDerivations) {
+        for (PathSet::iterator i = livePaths.begin();
+             i != livePaths.end(); ++i)
+        {
+            Path deriver = queryDeriver(noTxn, *i);
+            if (deriver != "")
+                computeFSClosure(deriver, livePaths);
+        }
+    }
+
     if (gcKeepOutputs) {
         /* Hmz, identical to storePathRequisites in nix-store. */
         for (PathSet::iterator i = livePaths.begin();