Merge pull request #6227 from NixOS/impure-derivations-ng

Impure derivations

3 files changed, 122 insertions, 1 deletions

diff --git a/tests/impure-derivations.nix b/tests/impure-derivations.nix
new file mode 100644
index 000000000..98547e6c1
--- /dev/null
+++ b/tests/impure-derivations.nix
@@ -0,0 +1,63 @@
+with import ./config.nix;
+
+rec {
+
+  impure = mkDerivation {
+    name = "impure";
+    outputs = [ "out" "stuff" ];
+    buildCommand =
+      ''
+        echo impure
+        x=$(< $TEST_ROOT/counter)
+        mkdir $out $stuff
+        echo $x > $out/n
+        ln -s $out/n $stuff/bla
+        printf $((x + 1)) > $TEST_ROOT/counter
+      '';
+    __impure = true;
+    impureEnvVars = [ "TEST_ROOT" ];
+  };
+
+  impureOnImpure = mkDerivation {
+    name = "impure-on-impure";
+    buildCommand =
+      ''
+        echo impure-on-impure
+        x=$(< ${impure}/n)
+        mkdir $out
+        printf X$x > $out/n
+        ln -s ${impure.stuff} $out/symlink
+        ln -s $out $out/self
+      '';
+    __impure = true;
+  };
+
+  # This is not allowed.
+  inputAddressed = mkDerivation {
+    name = "input-addressed";
+    buildCommand =
+      ''
+        cat ${impure} > $out
+      '';
+  };
+
+  contentAddressed = mkDerivation {
+    name = "content-addressed";
+    buildCommand =
+      ''
+        echo content-addressed
+        x=$(< ${impureOnImpure}/n)
+        printf ''${x:0:1} > $out
+      '';
+    outputHashMode = "recursive";
+    outputHash = "sha256-eBYxcgkuWuiqs4cKNgKwkb3vY/HR0vVsJnqe8itJGcQ=";
+  };
+
+  inputAddressedAfterCA = mkDerivation {
+    name = "input-addressed-after-ca";
+    buildCommand =
+      ''
+        cat ${contentAddressed} > $out
+      '';
+  };
+}
diff --git a/tests/impure-derivations.sh b/tests/impure-derivations.sh
new file mode 100644
index 000000000..35ae3f5d3
--- /dev/null
+++ b/tests/impure-derivations.sh
@@ -0,0 +1,57 @@
+source common.sh
+
+requireDaemonNewerThan "2.8pre20220311"
+
+enableFeatures "ca-derivations ca-references impure-derivations"
+restartDaemon
+
+set -o pipefail
+
+clearStore
+
+# Basic test of impure derivations: building one a second time should not use the previous result.
+printf 0 > $TEST_ROOT/counter
+
+json=$(nix build -L --no-link --json --file ./impure-derivations.nix impure.all)
+path1=$(echo $json | jq -r .[].outputs.out)
+path1_stuff=$(echo $json | jq -r .[].outputs.stuff)
+[[ $(< $path1/n) = 0 ]]
+[[ $(< $path1_stuff/bla) = 0 ]]
+
+[[ $(nix path-info --json $path1 | jq .[].ca) =~ fixed:r:sha256: ]]
+
+path2=$(nix build -L --no-link --json --file ./impure-derivations.nix impure | jq -r .[].outputs.out)
+[[ $(< $path2/n) = 1 ]]
+
+# Test impure derivations that depend on impure derivations.
+path3=$(nix build -L --no-link --json --file ./impure-derivations.nix impureOnImpure | jq -r .[].outputs.out)
+[[ $(< $path3/n) = X2 ]]
+
+path4=$(nix build -L --no-link --json --file ./impure-derivations.nix impureOnImpure | jq -r .[].outputs.out)
+[[ $(< $path4/n) = X3 ]]
+
+# Test that (self-)references work.
+[[ $(< $path4/symlink/bla) = 3 ]]
+[[ $(< $path4/self/n) = X3 ]]
+
+# Input-addressed derivations cannot depend on impure derivations directly.
+(! nix build -L --no-link --json --file ./impure-derivations.nix inputAddressed 2>&1) | grep 'depends on impure derivation'
+
+drvPath=$(nix eval --json --file ./impure-derivations.nix impure.drvPath | jq -r .)
+[[ $(nix show-derivation $drvPath | jq ".[\"$drvPath\"].outputs.out.impure") = true ]]
+[[ $(nix show-derivation $drvPath | jq ".[\"$drvPath\"].outputs.stuff.impure") = true ]]
+
+# Fixed-output derivations *can* depend on impure derivations.
+path5=$(nix build -L --no-link --json --file ./impure-derivations.nix contentAddressed | jq -r .[].outputs.out)
+[[ $(< $path5) = X ]]
+[[ $(< $TEST_ROOT/counter) = 5 ]]
+
+# And they should not be rebuilt.
+path5=$(nix build -L --no-link --json --file ./impure-derivations.nix contentAddressed | jq -r .[].outputs.out)
+[[ $(< $path5) = X ]]
+[[ $(< $TEST_ROOT/counter) = 5 ]]
+
+# Input-addressed derivations can depend on fixed-output derivations that depend on impure derivations.
+path6=$(nix build -L --no-link --json --file ./impure-derivations.nix inputAddressedAfterCA | jq -r .[].outputs.out)
+[[ $(< $path6) = X ]]
+[[ $(< $TEST_ROOT/counter) = 5 ]]
diff --git a/tests/local.mk b/tests/local.mk
index 97971dd76..668b34500 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -97,7 +97,8 @@ nix_tests = \
   nix-profile.sh \
   suggestions.sh \
   store-ping.sh \
-  fetchClosure.sh
+  fetchClosure.sh \
+  impure-derivations.sh
 
 ifeq ($(HAVE_LIBCPUID), 1)
 	nix_tests += compute-levels.sh