harlequin: pin textual to 8.2.4

pkgs/by-name/ha/harlequin/package.nix

@@ -1,7 +1,7 @@
 {
   lib,
   stdenv,
-  python3Packages,
+  python3,
   fetchFromGitHub,
   nix-update-script,
   glibcLocales,
@@ -10,6 +10,23 @@
   withPostgresAdapter ? true,
   withBigQueryAdapter ? true,
 }:
+
+let
+  python = python3.override {
+    packageOverrides = _final: prev: {
+      # throws a runtime error with textual 8.2.5:
+      # KeyError: 'textual-ansi'
+      textual = prev.textual.overridePythonAttrs (old: rec {
+        version = "8.2.4";
+        src = old.src.override {
+          tag = "v${version}";
+          hash = "sha256-827cm9pcj1o1FYeaoWKCJ6dEyXeDop4kYd205cySTfg=";
+        };
+      });
+    };
+  };
+  python3Packages = python.pkgs;
+in
 python3Packages.buildPythonApplication (finalAttrs: {
   pname = "harlequin";
   version = "2.5.2";