From 2cf591a134f3ec6f634b47eeb522f422c64a9d33 Mon Sep 17 00:00:00 2001
From: regnat <rg@regnat.ovh>
Date: Fri, 11 Jun 2021 13:31:19 +0200
Subject: [PATCH 1/2] Make `nix develop` work with CA derivations

Fix #4823
---
 src/nix/develop.cc | 30 +++++++++++++++++++-----------
 tests/nix-shell.sh | 12 ++++++++++--
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/nix/develop.cc b/src/nix/develop.cc
index 10f843651..aeeaf3e13 100644
--- a/src/nix/develop.cc
+++ b/src/nix/develop.cc
@@ -144,17 +144,26 @@ StorePath getDerivationEnvironment(ref<Store> store, const StorePath & drvPath)
     /* Rehash and write the derivation. FIXME: would be nice to use
        'buildDerivation', but that's privileged. */
     drv.name += "-env";
-    for (auto & output : drv.outputs) {
-        output.second = { .output = DerivationOutputInputAddressed { .path = StorePath::dummy } };
-        drv.env[output.first] = "";
-    }
     drv.inputSrcs.insert(std::move(getEnvShPath));
-    Hash h = std::get<0>(hashDerivationModulo(*store, drv, true));
+    if (settings.isExperimentalFeatureEnabled("ca-derivations")) {
+        for (auto & output : drv.outputs) {
+            output.second = {
+                .output = DerivationOutputDeferred{},
+            };
+            drv.env[output.first] = "";
+        }
+    } else {
+        for (auto & output : drv.outputs) {
+            output.second = { .output = DerivationOutputInputAddressed { .path = StorePath::dummy } };
+            drv.env[output.first] = "";
+        }
+        Hash h = std::get<0>(hashDerivationModulo(*store, drv, true));
 
-    for (auto & output : drv.outputs) {
-        auto outPath = store->makeOutputPath(output.first, h, drv.name);
-        output.second = { .output = DerivationOutputInputAddressed { .path = outPath } };
-        drv.env[output.first] = store->printStorePath(outPath);
+        for (auto & output : drv.outputs) {
+            auto outPath = store->makeOutputPath(output.first, h, drv.name);
+            output.second = { .output = DerivationOutputInputAddressed { .path = outPath } };
+            drv.env[output.first] = store->printStorePath(outPath);
+        }
     }
 
     auto shellDrvPath = writeDerivation(*store, drv);
@@ -162,8 +171,7 @@ StorePath getDerivationEnvironment(ref<Store> store, const StorePath & drvPath)
     /* Build the derivation. */
     store->buildPaths({DerivedPath::Built{shellDrvPath}});
 
-    for (auto & [_0, outputAndOptPath] : drv.outputsAndOptPaths(*store)) {
-        auto & [_1, optPath] = outputAndOptPath;
+    for (auto & [_0, optPath] : store->queryPartialDerivationOutputMap(shellDrvPath)) {
         assert(optPath);
         auto & outPath = *optPath;
         assert(store->isValidPath(outPath));
diff --git a/tests/nix-shell.sh b/tests/nix-shell.sh
index e3174dac1..3481c2c69 100644
--- a/tests/nix-shell.sh
+++ b/tests/nix-shell.sh
@@ -6,6 +6,14 @@ if [[ -n ${CONTENT_ADDRESSED:-} ]]; then
     nix-shell () {
         command nix-shell --arg contentAddressed true "$@"
     }
+
+    nix_develop() {
+        nix develop --arg contentAddressed true "$@"
+    }
+else
+    nix_develop() {
+        nix develop "$@"
+    }
 fi
 
 # Test nix-shell -A
@@ -79,13 +87,13 @@ output=$($TEST_ROOT/spaced\ \\\'\"shell.shebang.rb abc ruby)
 [ "$output" = '-e load(ARGV.shift) -- '"$TEST_ROOT"'/spaced \'\''"shell.shebang.rb abc ruby' ]
 
 # Test 'nix develop'.
-nix develop -f shell.nix shellDrv -c bash -c '[[ -n $stdenv ]]'
+nix_develop -f shell.nix shellDrv -c bash -c '[[ -n $stdenv ]]'
 
 # Ensure `nix develop -c` preserves stdin
 echo foo | nix develop -f shell.nix shellDrv -c cat | grep -q foo
 
 # Ensure `nix develop -c` actually executes the command if stdout isn't a terminal
-nix develop -f shell.nix shellDrv -c echo foo |& grep -q foo
+nix_develop -f shell.nix shellDrv -c echo foo |& grep -q foo
 
 # Test 'nix print-dev-env'.
 source <(nix print-dev-env -f shell.nix shellDrv)

From ce674cb2cf97fc14ce48acef7f8ef88f4ac771f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophane=20Hufschmitt?=
 <regnat@users.noreply.github.com>
Date: Mon, 21 Jun 2021 15:52:01 +0200
Subject: [PATCH 2/2] Properly set the output env variables

Co-authored-by: John Ericson <git@JohnEricson.me>
---
 src/nix/develop.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/nix/develop.cc b/src/nix/develop.cc
index aeeaf3e13..350b08648 100644
--- a/src/nix/develop.cc
+++ b/src/nix/develop.cc
@@ -150,7 +150,7 @@ StorePath getDerivationEnvironment(ref<Store> store, const StorePath & drvPath)
             output.second = {
                 .output = DerivationOutputDeferred{},
             };
-            drv.env[output.first] = "";
+            drv.env[output.first] = hashPlaceholder(output.first);
         }
     } else {
         for (auto & output : drv.outputs) {