diff --git a/pkgs/build-support/php/builders/v2/build-composer-project.nix b/pkgs/build-support/php/builders/v2/build-composer-project.nix
index bfbd2327812bc..a777b8a830e21 100644
--- a/pkgs/build-support/php/builders/v2/build-composer-project.nix
+++ b/pkgs/build-support/php/builders/v2/build-composer-project.nix
@@ -3,100 +3,114 @@
   stdenvNoCC,
   lib,
   php,
-}:
+}@toplevel:
 
 let
   buildComposerProjectOverride =
-    finalAttrs: previousAttrs:
-
-    let
-      phpDrv = finalAttrs.php or php;
-      composer = finalAttrs.composer or phpDrv.packages.composer;
-    in
+    finalAttrs:
     {
-      composerLock = previousAttrs.composerLock or null;
-      composerNoDev = previousAttrs.composerNoDev or true;
-      composerNoPlugins = previousAttrs.composerNoPlugins or true;
-      composerNoScripts = previousAttrs.composerNoScripts or true;
-      composerStrictValidation = previousAttrs.composerStrictValidation or true;
-
-      nativeBuildInputs = (previousAttrs.nativeBuildInputs or [ ]) ++ [
+      php ? toplevel.php,
+      composer ? toplevel.php.packages.composer,
+      composerVendor ? null,
+      vendorHash ? null,
+      composerLock ? null,
+      composerNoDev ? true,
+      composerNoPlugins ? true,
+      composerNoScripts ? true,
+      composerStrictValidation ? true,
+      buildInputs ? [ ],
+      nativeBuildInputs ? [ ],
+      strictDeps ? true,
+      patches ? [ ],
+      doCheck ? true,
+      doInstallCheck ? true,
+      passthru ? { },
+      meta ? { },
+      ...
+    }@args:
+    {
+      inherit
+        patches
+        strictDeps
+        doCheck
+        doInstallCheck
+        ;
+      nativeBuildInputs = nativeBuildInputs ++ [
         composer
-        phpDrv
-        phpDrv.composerHooks2.composerInstallHook
+        php
+        php.composerHooks2.composerInstallHook
       ];
 
-      buildInputs = (previousAttrs.buildInputs or [ ]) ++ [ phpDrv ];
-
-      patches = previousAttrs.patches or [ ];
-      strictDeps = previousAttrs.strictDeps or true;
+      buildInputs = buildInputs ++ [ php ];
 
       # Should we keep these empty phases?
       configurePhase =
-        previousAttrs.configurePhase or ''
+        args.configurePhase or ''
           runHook preConfigure
 
           runHook postConfigure
         '';
 
       buildPhase =
-        previousAttrs.buildPhase or ''
+        args.buildPhase or ''
           runHook preBuild
 
           runHook postBuild
         '';
 
-      doCheck = previousAttrs.doCheck or true;
       checkPhase =
-        previousAttrs.checkPhase or ''
+        args.checkPhase or ''
           runHook preCheck
 
           runHook postCheck
         '';
 
       installPhase =
-        previousAttrs.installPhase or ''
+        args.installPhase or ''
           runHook preInstall
 
           runHook postInstall
         '';
 
-      doInstallCheck = previousAttrs.doInstallCheck or false;
       installCheckPhase =
-        previousAttrs.installCheckPhase or ''
+        args.installCheckPhase or ''
           runHook preInstallCheck
 
           runHook postInstallCheck
         '';
 
       composerVendor =
-        previousAttrs.composerVendor or (phpDrv.mkComposerVendor {
-          inherit composer;
+        args.composerVendor or (php.mkComposerVendor {
+          inherit
+            composer
+            composerLock
+            composerNoDev
+            composerNoPlugins
+            composerNoScripts
+            composerStrictValidation
+            vendorHash
+            ;
           inherit (finalAttrs)
             patches
             pname
             src
-            vendorHash
             version
             ;
-
-          composerLock = previousAttrs.composerLock or null;
-          composerNoDev = previousAttrs.composerNoDev or true;
-          composerNoPlugins = previousAttrs.composerNoPlugins or true;
-          composerNoScripts = previousAttrs.composerNoScripts or true;
-          composerStrictValidation = previousAttrs.composerStrictValidation or true;
         });
 
       # Projects providing a lockfile from upstream can be automatically updated.
-      passthru = previousAttrs.passthru or { } // {
+      passthru = passthru // {
         updateScript =
-          previousAttrs.passthru.updateScript
+          args.passthru.updateScript
             or (if finalAttrs.composerVendor.composerLock == null then nix-update-script { } else null);
       };
 
-      meta = previousAttrs.meta or { } // {
+      meta = meta // {
         platforms = lib.platforms.all;
       };
     };
 in
-args: (stdenvNoCC.mkDerivation args).overrideAttrs buildComposerProjectOverride
+lib.extendMkDerivation {
+  constructDrv = stdenvNoCC.mkDerivation;
+  extendDrvArgs = buildComposerProjectOverride;
+}
diff --git a/pkgs/build-support/php/builders/v2/build-composer-vendor.nix b/pkgs/build-support/php/builders/v2/build-composer-vendor.nix
index 75f93d066f839..c66dedb614da8 100644
--- a/pkgs/build-support/php/builders/v2/build-composer-vendor.nix
+++ b/pkgs/build-support/php/builders/v2/build-composer-vendor.nix
@@ -2,86 +2,77 @@
   stdenvNoCC,
   lib,
   php,
-}:
+}@toplevel:
 
 let
   mkComposerVendorOverride =
-    /*
-      We cannot destruct finalAttrs since the attrset below is used to construct it
-      and Nix currently does not support lazy attribute names.
-      {
-      php ? null,
-      composer ? null,
-      composerLock ? "composer.lock",
-      src,
-      vendorHash,
+    finalAttrs:
+    {
+      php ? toplevel.php,
+      composer ? toplevel.php.packages.composer,
+      composerLock,
+      vendorHash ? null,
+      composerNoDev ? true,
+      composerNoPlugins ? true,
+      composerNoScripts ? true,
+      composerStrictValidation ? true,
+      buildInputs ? [ ],
+      nativeBuildInputs ? [ ],
+      dontPatchShebangs ? true,
+      strictDeps ? true,
+      doCheck ? true,
+      doInstallCheck ? false,
       ...
-      }@finalAttrs:
-    */
-    finalAttrs: previousAttrs:
-
-    let
-      phpDrv = finalAttrs.php or php;
-      composer = finalAttrs.composer or phpDrv.packages.composer;
-    in
-    assert (lib.assertMsg (previousAttrs ? src) "mkComposerVendor expects src argument.");
-    assert (lib.assertMsg (previousAttrs ? vendorHash) "mkComposerVendor expects vendorHash argument.");
-    assert (lib.assertMsg (previousAttrs ? version) "mkComposerVendor expects version argument.");
-    assert (lib.assertMsg (previousAttrs ? pname) "mkComposerVendor expects pname argument.");
+    }@args:
+    assert (lib.assertMsg (args ? src) "mkComposerVendor expects src argument.");
+    assert (lib.assertMsg (args ? vendorHash) "mkComposerVendor expects vendorHash argument.");
+    assert (lib.assertMsg (args ? version) "mkComposerVendor expects version argument.");
+    assert (lib.assertMsg (args ? pname) "mkComposerVendor expects pname argument.");
     {
-      composerNoDev = previousAttrs.composerNoDev or true;
-      composerNoPlugins = previousAttrs.composerNoPlugins or true;
-      composerNoScripts = previousAttrs.composerNoScripts or true;
-      composerStrictValidation = previousAttrs.composerStrictValidation or true;
-
-      name = "${previousAttrs.pname}-composer-repository-${previousAttrs.version}";
+      name = "${args.pname}-composer-vendor-${args.version}";
 
       # See https://github.com/NixOS/nix/issues/6660
-      dontPatchShebangs = previousAttrs.dontPatchShebangs or true;
+      inherit dontPatchShebangs;
 
-      nativeBuildInputs = (previousAttrs.nativeBuildInputs or [ ]) ++ [
+      inherit buildInputs strictDeps doCheck;
+
+      nativeBuildInputs = nativeBuildInputs ++ [
         composer
-        phpDrv
-        phpDrv.composerHooks2.composerVendorHook
+        php
+        php.composerHooks2.composerVendorHook
       ];
 
-      buildInputs = previousAttrs.buildInputs or [ ];
-
-      strictDeps = previousAttrs.strictDeps or true;
-
       # Should we keep these empty phases?
       configurePhase =
-        previousAttrs.configurePhase or ''
+        args.configurePhase or ''
           runHook preConfigure
 
           runHook postConfigure
         '';
 
       buildPhase =
-        previousAttrs.buildPhase or ''
+        args.buildPhase or ''
           runHook preBuild
 
           runHook postBuild
         '';
 
-      doCheck = previousAttrs.doCheck or true;
       checkPhase =
-        previousAttrs.checkPhase or ''
+        args.checkPhase or ''
           runHook preCheck
 
           runHook postCheck
         '';
 
       installPhase =
-        previousAttrs.installPhase or ''
+        args.installPhase or ''
           runHook preInstall
 
           runHook postInstall
         '';
 
-      doInstallCheck = previousAttrs.doInstallCheck or false;
       installCheckPhase =
-        previousAttrs.installCheckPhase or ''
+        args.installCheckPhase or ''
           runHook preInstallCheck
 
           runHook postInstallCheck
@@ -90,7 +81,10 @@ let
       outputHashMode = "recursive";
       outputHashAlgo =
         if (finalAttrs ? vendorHash && finalAttrs.vendorHash != "") then null else "sha256";
-      outputHash = finalAttrs.vendorHash or "";
+      outputHash = vendorHash;
     };
 in
-args: (stdenvNoCC.mkDerivation args).overrideAttrs mkComposerVendorOverride
+lib.extendMkDerivation {
+  constructDrv = stdenvNoCC.mkDerivation;
+  extendDrvArgs = mkComposerVendorOverride;
+}