uiua{,-unstable}: use lib.fix to reference self, rename unstable flag to uiua_versionType (#365712)

pkgs/by-name/ui/uiua/package.nix

@@ -1,4 +1,6 @@
 {
+  uiua_versionType ? "stable",
+
   lib,
   stdenv,
   rustPlatform,
@@ -10,16 +12,21 @@
   alsa-lib,
   webcamSupport ? false,
 
-  # passthru.tests.run
   runCommand,
-  uiua,
-
-  unstable ? false,
 }:
 
 let
-  versionInfo = import (if unstable then ./unstable.nix else ./stable.nix);
+  versionInfo =
+    {
+      "stable" = import ./stable.nix;
+      "unstable" = import ./unstable.nix;
+    }
+    .${uiua_versionType};
 in
+
+# buildRustPackage doesn't support finalAttrs, so we can't use finalPackage for the tests
+lib.fix (
+  uiua:
   rustPlatform.buildRustPackage rec {
     pname = "uiua";
     inherit (versionInfo) version cargoHash;
@@ -68,3 +75,4 @@ rustPlatform.buildRustPackage rec {
       ];
     };
   }
+)

pkgs/top-level/all-packages.nix

@@ -7090,7 +7090,7 @@ with pkgs;
   babashka-unwrapped = callPackage ../development/interpreters/babashka { };
   babashka = callPackage ../development/interpreters/babashka/wrapped.nix { };
 
-  uiua-unstable = callPackage ../by-name/ui/uiua/package.nix { unstable = true; };
+  uiua-unstable = callPackage ../by-name/ui/uiua/package.nix { uiua_versionType = "unstable"; };
 
   # BQN interpreters and compilers