diff --git a/lib/attrsets.nix b/lib/attrsets.nix
index 5575e9577029ae6..de88763854d6953 100644
--- a/lib/attrsets.nix
+++ b/lib/attrsets.nix
@@ -622,6 +622,20 @@ rec {
   dontRecurseIntoAttrs =
     attrs: attrs // { recurseForDerivations = false; };
 
+  /* `unionOfDisjoint x y` is equal to `x // y // z` where the
+     attrnames in `z` are the intersection of the attrnames in `x` and
+     `y`, and all values `assert` with an error message.  This
+      operator is commutative, unlike (//). */
+  unionOfDisjoint = x: y:
+    let
+      intersection = builtins.intersectAttrs x y;
+      collisions = lib.concatStringsSep " " (builtins.attrNames intersection);
+      mask = builtins.mapAttrs (name: value: builtins.throw
+        "unionOfDisjoint: collision on ${name}; complete list: ${collisions}")
+        intersection;
+    in
+      (x // y) // mask;
+
   /*** deprecated stuff ***/
 
   zipWithNames = zipAttrsWithNames;
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index f2c6b822923859f..3ecb1dcd68f538a 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -2186,7 +2186,10 @@ with pkgs;
 
   brewtarget = libsForQt514.callPackage ../applications/misc/brewtarget { } ;
 
-  stdenvBootstrapTools = if stdenv.hostPlatform.isDarwin then
+  # Derivation's result is not used by nixpkgs. Useful for validation for
+  # regressions of bootstrapTools on hydra and on ofborg. Example:
+  #     pkgsCross.aarch64-multiplatform.freshBootstrapTools.build
+  freshBootstrapTools = if stdenv.hostPlatform.isDarwin then
     callPackage ../stdenv/darwin/make-bootstrap-tools.nix {
       localSystem = stdenv.buildPlatform;
       crossSystem =
@@ -2194,7 +2197,7 @@ with pkgs;
     }
   else if stdenv.hostPlatform.isLinux then
     callPackage ../stdenv/linux/make-bootstrap-tools.nix {}
-  else throw "stdenvBootstrapTools: unknown hostPlatform ${stdenv.hostPlatform.config}";
+  else throw "freshBootstrapTools: unknown hostPlatform ${stdenv.hostPlatform.config}";
 
   boxes = callPackage ../tools/text/boxes { };
 
diff --git a/pkgs/top-level/release.nix b/pkgs/top-level/release.nix
index bac3d1b1171ddb6..61116328b29f506 100644
--- a/pkgs/top-level/release.nix
+++ b/pkgs/top-level/release.nix
@@ -30,7 +30,7 @@ let
     "aarch64"
   ] (arch: builtins.elem "${arch}-darwin" systemsWithAnySupport);
 
-  jobs =
+  nonPackageJobs =
     { tarball = import ./make-tarball.nix { inherit pkgs nixpkgs officialRelease supportedSystems; };
 
       metrics = import ./metrics.nix { inherit pkgs nixpkgs; };
@@ -167,7 +167,9 @@ let
           (system: {
             inherit
               (import ../stdenv/linux/make-bootstrap-tools.nix {
-                localSystem = { inherit system; };
+                pkgs = import ../.. {
+                  localSystem = { inherit system; };
+                };
               })
               dist test;
           })
@@ -175,7 +177,9 @@ let
         // optionalAttrs supportDarwin.x86_64 {
           x86_64-darwin =
             let
-              bootstrap = import ../stdenv/darwin/make-bootstrap-tools.nix { system = "x86_64-darwin"; };
+              bootstrap = import ../stdenv/darwin/make-bootstrap-tools.nix {
+                localSystem = { system = "x86_64-darwin"; };
+              };
             in {
               # Lightweight distribution and test
               inherit (bootstrap) dist test;
@@ -186,14 +190,25 @@ let
           # Cross compiled bootstrap tools
           aarch64-darwin =
             let
-              bootstrap = import ../stdenv/darwin/make-bootstrap-tools.nix { system = "x86_64-darwin"; crossSystem = "aarch64-darwin"; };
+              bootstrap = import ../stdenv/darwin/make-bootstrap-tools.nix {
+                localSystem = { system = "x86_64-darwin"; };
+                crossSystem = { system = "aarch64-darwin"; };
+              };
             in {
               # Distribution only for now
               inherit (bootstrap) dist;
             };
           };
 
-    } // (mapTestOn ((packagePlatforms pkgs) // {
+       };
+
+  # Do not allow attribute collision between jobs inserted in
+  # 'nonPackageAttrs' and jobs pulled in from 'pkgs'.
+  # Conflicts usually cause silent job drops like in
+  #   https://github.com/NixOS/nixpkgs/pull/182058
+  jobs = lib.attrsets.unionOfDisjoint
+    nonPackageJobs
+    (mapTestOn ((packagePlatforms pkgs) // {
       haskell.compiler = packagePlatforms pkgs.haskell.compiler;
       haskellPackages = packagePlatforms pkgs.haskellPackages;
       idrisPackages = packagePlatforms pkgs.idrisPackages;