devShellTools.{unstructuredDerivationInputEnv,derivationOutputEnv}: extract

pkgs/build-support/dev-shell-tools/default.nix

@@ -1,4 +1,7 @@
-{ lib }:
+{
+  lib,
+  writeText,
+}:
 let
   inherit (builtins) typeOf;
 in
@@ -13,4 +16,24 @@ rec {
     if typeOf value == "path" then "${value}"
     else if typeOf value == "list" then toString (map valueToString value)
     else toString value;
+
+
+  # https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L992-L1004
+  unstructuredDerivationInputEnv = { drvAttrs }:
+    # FIXME: this should be `normalAttrs // passAsFileAttrs`
+    lib.mapAttrs'
+      (name: value:
+        let str = valueToString value;
+        in if lib.elem name (drvAttrs.passAsFile or [])
+        then lib.nameValuePair "${name}Path" (writeText "pass-as-text-${name}" str)
+        else lib.nameValuePair name str
+      )
+      drvAttrs;
+
+  derivationOutputEnv = { outputList, outputMap }:
+    # A mapping from output name to the nix store path where they should end up
+    # https://github.com/NixOS/nix/blob/2.8.0/src/libexpr/primops.cc#L1253
+    lib.genAttrs outputList (output: builtins.unsafeDiscardStringContext outputMap.${output}.outPath);
+
+
 }

pkgs/build-support/docker/default.nix

@@ -1190,16 +1190,9 @@ rec {
         # https://github.com/NixOS/nix/blob/2.8.0/src/libstore/globals.hh#L464-L465
         sandboxBuildDir = "/build";
 
-        # https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L992-L1004
-        drvEnv = lib.mapAttrs' (name: value:
-          let str = valueToString value;
-          in if lib.elem name (drv.drvAttrs.passAsFile or [])
-          then lib.nameValuePair "${name}Path" (writeText "pass-as-text-${name}" str)
-          else lib.nameValuePair name str
-        ) drv.drvAttrs //
-          # A mapping from output name to the nix store path where they should end up
-          # https://github.com/NixOS/nix/blob/2.8.0/src/libexpr/primops.cc#L1253
-          lib.genAttrs drv.outputs (output: builtins.unsafeDiscardStringContext drv.${output}.outPath);
+        drvEnv =
+          devShellTools.unstructuredDerivationInputEnv { inherit (drv) drvAttrs; }
+          // devShellTools.derivationOutputEnv { outputList = drv.outputs; outputMap = drv; };
 
         # Environment variables set in the image
         envVars = {