buildDartApplication: Accept additional package_config.json setup commands

pkgs/build-support/dart/build-dart-application/default.nix

···
 
 , sdkSetupScript ? ""
 , pubGetScript ? "dart pub get"
+, extraPackageConfigSetup ? ""
 
   # Output type to produce. Can be any kind supported by dart
   # https://dart.dev/tools/dart-compile#types-of-output
···
 
   pubspecLockFile = builtins.toJSON pubspecLock;
   pubspecLockData = pub2nix.readPubspecLock { inherit src packageRoot pubspecLock gitHashes sdkSourceBuilders; };
-  packageConfig = generators.linkPackageConfig (pub2nix.generatePackageConfig {
-    pname = if args.pname != null then "${args.pname}-${args.version}" else null;
+  packageConfig = generators.linkPackageConfig {
+    packageConfig = pub2nix.generatePackageConfig {
+      pname = if args.pname != null then "${args.pname}-${args.version}" else null;
 
-    dependencies =
-      # Ideally, we'd only include the main dependencies and their transitive
-      # dependencies.
-      #
-      # The pubspec.lock file does not contain information about where
-      # transitive dependencies come from, though, and it would be weird to
-      # include the transitive dependencies of dev and override dependencies
-      # without including the dev and override dependencies themselves.
-      builtins.concatLists (builtins.attrValues pubspecLockData.dependencies);
+      dependencies =
+        # Ideally, we'd only include the main dependencies and their transitive
+        # dependencies.
+        #
+        # The pubspec.lock file does not contain information about where
+        # transitive dependencies come from, though, and it would be weird to
+        # include the transitive dependencies of dev and override dependencies
+        # without including the dev and override dependencies themselves.
+        builtins.concatLists (builtins.attrValues pubspecLockData.dependencies);
 
-    inherit (pubspecLockData) dependencySources;
-  });
+      inherit (pubspecLockData) dependencySources;
+    };
+    extraSetupCommands = extraPackageConfigSetup;
+  };
 
   inherit (dartHooks.override { inherit dart; }) dartConfigHook dartBuildHook dartInstallHook dartFixupHook;
 

pkgs/build-support/dart/build-dart-application/generators.nix

···
   name = (if drvArgs ? name then drvArgs.name else "${drvArgs.pname}-${drvArgs.version}");
 
   # Adds the root package to a dependency package_config.json file from pub2nix.
-  linkPackageConfig = packageConfig: stdenvNoCC.mkDerivation (drvArgs // {
+  linkPackageConfig = { packageConfig, extraSetupCommands ? "" }: stdenvNoCC.mkDerivation (drvArgs // {
     name = "${name}-package-config-with-root.json";
 
     nativeBuildInputs = drvArgs.nativeBuildInputs or [ ] ++ args.nativeBuildInputs or [ ] ++ [ jq yq ];
···
 
       packageName="$(yq --raw-output .name pubspec.yaml)"
       jq --arg name "$packageName" '.packages |= . + [{ name: $name, rootUri: "../", packageUri: "lib/" }]' '${packageConfig}' > "$out"
+      ${extraSetupCommands}
 
       runHook postInstall
     '';