diff --git a/nixos/doc/manual/release-notes/rl-2505.section.md b/nixos/doc/manual/release-notes/rl-2505.section.md
index 55d7d8e12cd7..c4831db15b3e 100644
--- a/nixos/doc/manual/release-notes/rl-2505.section.md
+++ b/nixos/doc/manual/release-notes/rl-2505.section.md
@@ -204,6 +204,9 @@
 
 - `pkgs.nextcloud28` has been removed since it's out of support upstream.
 
+- Emacs lisp build helpers, such as `emacs.pkgs.melpaBuild`, now enables `__structuredAttrs` by default.
+  Environment variables have to be passed via the `env` attribute.
+
 - `buildGoModule` now passes environment variables via the `env` attribute. `CGO_ENABLED` should now be specified with `env.CGO_ENABLED` when passing to buildGoModule. Direct specification of `CGO_ENABLED` is now redirected by a compatibility layer with a warning, but will become an error in future releases.
 
   Go-related environment variables previously shadowed by `buildGoModule` now results in errors when specified directly. Such variables include `GOOS` and `GOARCH`.
diff --git a/pkgs/applications/editors/emacs/build-support/elpa.nix b/pkgs/applications/editors/emacs/build-support/elpa.nix
index fcaef43953ef..50abadccf9d9 100644
--- a/pkgs/applications/editors/emacs/build-support/elpa.nix
+++ b/pkgs/applications/editors/emacs/build-support/elpa.nix
@@ -43,7 +43,9 @@ lib.extendMkDerivation {
 
           emacs --batch -Q -l "$elpa2nix" \
               -f elpa2nix-install-package \
-              "$src" "$out/share/emacs/site-lisp/elpa"
+              "$src" "$out/share/emacs/site-lisp/elpa" \
+              ${if finalAttrs.turnCompilationWarningToError then "t" else "nil"} \
+              ${if finalAttrs.ignoreCompilationError then "t" else "nil"}
 
           runHook postInstall
         '';
diff --git a/pkgs/applications/editors/emacs/build-support/elpa2nix.el b/pkgs/applications/editors/emacs/build-support/elpa2nix.el
index 97cf2fd58a06..5b363b7b6640 100644
--- a/pkgs/applications/editors/emacs/build-support/elpa2nix.el
+++ b/pkgs/applications/editors/emacs/build-support/elpa2nix.el
@@ -5,8 +5,10 @@
   (if (not noninteractive)
       (error "`elpa2nix-install-package' is to be used only with -batch"))
   (pcase command-line-args-left
-    (`(,archive ,elpa)
-     (progn (setq package-user-dir elpa)
+    (`(,archive ,elpa ,turn-compilation-warning-to-error ,ignore-compilation-error)
+     (progn (setq byte-compile-error-on-warn (string= turn-compilation-warning-to-error "t"))
+            (setq byte-compile-debug (string= ignore-compilation-error "nil"))
+            (setq package-user-dir elpa)
             (elpa2nix-install-file archive)))))
 
 (defun elpa2nix-install-from-buffer ()
@@ -31,13 +33,3 @@ The file can either be a tar file or an Emacs Lisp file."
 
 ;; Allow installing package tarfiles larger than 10MB
 (setq large-file-warning-threshold nil)
-
-(let ((flag (getenv "turnCompilationWarningToError")))
-  (when (and flag
-             ;; we do not use `string-empty-p' because it requires subr-x in Emacs <= 26
-             (not (string= flag "")))
-    (setq byte-compile-error-on-warn t)))
-
-(let ((flag (getenv "ignoreCompilationError")))
-  (when (string= flag "")
-    (setq byte-compile-debug t)))
diff --git a/pkgs/applications/editors/emacs/build-support/generic.nix b/pkgs/applications/editors/emacs/build-support/generic.nix
index ddab4bc70a00..b4e96f6490fb 100644
--- a/pkgs/applications/editors/emacs/build-support/generic.nix
+++ b/pkgs/applications/editors/emacs/build-support/generic.nix
@@ -61,6 +61,7 @@ lib.extendMkDerivation {
       propagatedUserEnvPkgs = finalAttrs.packageRequires ++ propagatedUserEnvPkgs;
 
       strictDeps = args.strictDeps or true;
+      __structuredAttrs = args.__structuredAttrs or true;
 
       inherit turnCompilationWarningToError ignoreCompilationError;
 
diff --git a/pkgs/applications/editors/emacs/build-support/melpa.nix b/pkgs/applications/editors/emacs/build-support/melpa.nix
index bdca913e865d..876cf9a46ddc 100644
--- a/pkgs/applications/editors/emacs/build-support/melpa.nix
+++ b/pkgs/applications/editors/emacs/build-support/melpa.nix
@@ -185,7 +185,9 @@ lib.extendMkDerivation {
           emacs --batch -Q \
               -l "$elpa2nix" \
               -f elpa2nix-install-package \
-              "$archive" "$out/share/emacs/site-lisp/elpa"
+              "$archive" "$out/share/emacs/site-lisp/elpa" \
+              ${if finalAttrs.turnCompilationWarningToError then "t" else "nil"} \
+              ${if finalAttrs.ignoreCompilationError then "t" else "nil"}
 
           runHook postInstall
         '';
diff --git a/pkgs/applications/editors/emacs/elisp-packages/melpa-packages.nix b/pkgs/applications/editors/emacs/elisp-packages/melpa-packages.nix
index 2ed31090e106..40a6f2f7aec3 100644
--- a/pkgs/applications/editors/emacs/elisp-packages/melpa-packages.nix
+++ b/pkgs/applications/editors/emacs/elisp-packages/melpa-packages.nix
@@ -153,8 +153,10 @@ let
         # https://github.com/Golevka/emacs-clang-complete-async/issues/90
         auto-complete-clang-async = (addPackageRequires super.auto-complete-clang-async [ self.auto-complete ]).overrideAttrs (old: {
           buildInputs = old.buildInputs ++ [ pkgs.llvmPackages.llvm ];
-          CFLAGS = "-I${lib.getLib pkgs.llvmPackages.libclang}/include";
-          LDFLAGS = "-L${lib.getLib pkgs.llvmPackages.libclang}/lib";
+          env = old.env or { } // {
+            CFLAGS = "-I${lib.getLib pkgs.llvmPackages.libclang}/include";
+            LDFLAGS = "-L${lib.getLib pkgs.llvmPackages.libclang}/lib";
+          };
         });
 
         # part of a larger package
@@ -242,7 +244,7 @@ let
           #   - https://github.com/vedang/pdf-tools/issues/102
           #   - https://github.com/vedang/pdf-tools/issues/103
           #   - https://github.com/vedang/pdf-tools/issues/109
-          CXXFLAGS = "-std=c++17";
+          env = old.env or { } // { CXXFLAGS = "-std=c++17"; };
 
           nativeBuildInputs = old.nativeBuildInputs ++ [
             pkgs.autoconf
@@ -294,7 +296,7 @@ let
 
         irony = super.irony.overrideAttrs (old: {
           cmakeFlags = old.cmakeFlags or [ ] ++ [ "-DCMAKE_INSTALL_BINDIR=bin" ];
-          env.NIX_CFLAGS_COMPILE = "-UCLANG_RESOURCE_DIR";
+          env = old.env or { } // { NIX_CFLAGS_COMPILE = "-UCLANG_RESOURCE_DIR"; };
           preConfigure = ''
             pushd server
           '';