From c29fffeaaad8a3642acaf78fed4414cae30baf7d Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sun, 18 Oct 2020 14:21:53 +0200
Subject: [PATCH 1/3] DerivationGoal: only retry if output closure incomplete
 is only problem

(cherry picked from commit bd9eb5c743faf1b3c33f4e1c2ccf317977d4be9d)
---
 src/libstore/build.cc | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 4ba9a5385c0..d09db82fcc9 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1222,8 +1222,13 @@ void DerivationGoal::outputsSubstituted()
 
     /*  If the substitutes form an incomplete closure, then we should
         build the dependencies of this derivation, but after that, we
-        can still use the substitutes for this derivation itself. */
-    if (nrIncompleteClosure > 0) retrySubstitution = true;
+        can still use the substitutes for this derivation itself.
+
+        If the nrIncompleteClosure != nrFailed, we have another issue as well.
+        In particular, it may be the case that the hole in the closure is
+        an output of the current derivation, which causes a loop if retried.
+     */
+    if (nrIncompleteClosure > 0 && nrIncompleteClosure == nrFailed) retrySubstitution = true;
 
     nrFailed = nrNoSubstituters = nrIncompleteClosure = 0;
 

From e90530e491278169b501e53ce6773e253b45e15e Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sun, 18 Oct 2020 00:43:52 +0200
Subject: [PATCH 2/3] Tests for #3964

(cherry picked from commit ea8d32020e1e24576cf5e8ff1a835f149dbd81c3)
---
 tests/binary-cache.sh | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/tests/binary-cache.sh b/tests/binary-cache.sh
index eb58ae7c12a..7fc6a6fccda 100644
--- a/tests/binary-cache.sh
+++ b/tests/binary-cache.sh
@@ -168,3 +168,34 @@ clearCacheCache
 nix-store -r $outPath --substituters "file://$cacheDir2 file://$cacheDir" --trusted-public-keys "$publicKey"
 
 fi # HAVE_LIBSODIUM
+
+# Test against issue https://github.com/NixOS/nix/issues/3964
+#
+expr='
+  with import ./config.nix;
+  mkDerivation {
+    name = "multi-output";
+    buildCommand = "mkdir -p $out; echo foo > $doc; echo $doc > $out/docref";
+    outputs = ["out" "doc"];
+  }
+'
+outPath=$(nix-build --no-out-link -E "$expr")
+docPath=$(nix-store -q --references $outPath)
+
+# $ nix-store -q --tree $outPath
+# ...-multi-output
+# +---...-multi-output-doc
+
+nix copy --to "file://$cacheDir" $outPath
+
+hashpart() {
+  basename "$1" | cut -c1-32
+}
+
+# break the closure of out by removing doc
+rm $cacheDir/$(hashpart $docPath).narinfo
+
+nix-store --delete $outPath $docPath
+# -vvv is the level that logs during the loop
+timeout 60 nix-build -E "$expr" --option substituters "file://$cacheDir" \
+  --option trusted-binary-caches "file://$cacheDir"  --no-require-sigs

From 8388e2ea48f340e940005aa7ffbc94fe7681c766 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Tue, 22 Dec 2020 11:57:31 +0100
Subject: [PATCH 3/3] Revert "Tests for #3964"

This reverts commit e90530e491278169b501e53ce6773e253b45e15e.

It appears that this backported test relies on new functionality.

The error is:

    + nix copy --to file:///build/nix-test/binary-cache /build/nix-test/store/dckdy2xp7sn8qvyx8axxjq7clnxddri1-multi-output
    warning: you don't have Internet access; disabling some network-dependent features
    error: uploading to 'file:///build/nix-test/binary-cache/nar/0hpfhrig9h6fvbjmiwsb7zkaxr19vr2w048y4xb3nrs36bagf92n.nar.xz' is not supported
---
 tests/binary-cache.sh | 31 -------------------------------
 1 file changed, 31 deletions(-)

diff --git a/tests/binary-cache.sh b/tests/binary-cache.sh
index 7fc6a6fccda..eb58ae7c12a 100644
--- a/tests/binary-cache.sh
+++ b/tests/binary-cache.sh
@@ -168,34 +168,3 @@ clearCacheCache
 nix-store -r $outPath --substituters "file://$cacheDir2 file://$cacheDir" --trusted-public-keys "$publicKey"
 
 fi # HAVE_LIBSODIUM
-
-# Test against issue https://github.com/NixOS/nix/issues/3964
-#
-expr='
-  with import ./config.nix;
-  mkDerivation {
-    name = "multi-output";
-    buildCommand = "mkdir -p $out; echo foo > $doc; echo $doc > $out/docref";
-    outputs = ["out" "doc"];
-  }
-'
-outPath=$(nix-build --no-out-link -E "$expr")
-docPath=$(nix-store -q --references $outPath)
-
-# $ nix-store -q --tree $outPath
-# ...-multi-output
-# +---...-multi-output-doc
-
-nix copy --to "file://$cacheDir" $outPath
-
-hashpart() {
-  basename "$1" | cut -c1-32
-}
-
-# break the closure of out by removing doc
-rm $cacheDir/$(hashpart $docPath).narinfo
-
-nix-store --delete $outPath $docPath
-# -vvv is the level that logs during the loop
-timeout 60 nix-build -E "$expr" --option substituters "file://$cacheDir" \
-  --option trusted-binary-caches "file://$cacheDir"  --no-require-sigs