overlays: add frappix fixups for nixos-unstable (sql_metadata, rq_1)

Building the frappix hosts on nixos-unstable 3ec6363 fails in frappix's
python overlay:

- sql_metadata 2.12.0 pins sqlparse<0.6, nixpkgs ships 0.6.0. frappe
  itself needs 0.6 (MAX_GROUPING_TOKENS), and sql_metadata 3.x needs
  sqlglot >= 30 which nixpkgs lacks, so relax the pin. frappe only feeds it
  SELECT statements; the only regressions on 0.6 are CREATE TABLE IF NOT
  EXISTS name extraction.
- rq 1.16.2 test_parse_connection fails against redis-py 8.1 (extra
  himport_registry kwarg). Test-only; disable it.

nix flake check does not catch these: it only evaluates hosts.

overlays/default.nix

@@ -10,5 +10,7 @@
     frappixPythonOverlay = inputs.frappix.pythonOverlay.x86_64-linux;
     frappixToolsOverlay = inputs.frappix.toolsOverlay.x86_64-linux;
     frappixAppsOverlay = import ../pkgs/frappix/overlay.nix;
+    # Must be applied after frappixPythonOverlay (overrides packages from it).
+    frappixFixupsOverlay = import ./frappix-fixups.nix;
   };
 }

overlays/frappix-fixups.nix

@@ -0,0 +1,34 @@
+# Fixups for frappix's python overlay on current nixos-unstable. Everything
+# here belongs upstream in kurogeek/frappix; drop entries as they land.
+# Must be applied after frappixPythonOverlay.
+_final: prev:
+let
+  inherit (prev) lib;
+in
+{
+  pythonPackagesExtensions = prev.pythonPackagesExtensions ++ [
+    (_pyFinal: pyPrev: {
+      # frappe >= v15.120 needs sqlparse 0.6 (db_query.py touches
+      # sqlparse.engine.grouping.MAX_GROUPING_TOKENS), but every sql_metadata
+      # 2.x release pins sqlparse<0.6; the sqlglot-based 3.x needs sqlglot >= 30,
+      # which nixpkgs does not ship yet. Relaxing the pin is safe for frappe: its
+      # two call sites (desk/reportview.py, core/doctype/recorder/db_optimizer.py)
+      # only parse SELECT statements, and the only sql_metadata test regressions
+      # on sqlparse 0.6 are `CREATE TABLE IF NOT EXISTS` name extraction (2/150).
+      sql_metadata =
+        if lib.versionAtLeast pyPrev.sql_metadata.version "3" then
+          lib.warn "frappix ships sql_metadata ${pyPrev.sql_metadata.version} (no sqlparse dependency): drop the sql_metadata entry from overlays/frappix-fixups.nix" pyPrev.sql_metadata
+        else
+          pyPrev.sql_metadata.overridePythonAttrs (old: {
+            pythonRelaxDeps = (old.pythonRelaxDeps or [ ]) ++ [ "sqlparse" ];
+          });
+
+      # rq 1.16.2 (frappix's rq_1 pin): test_parse_connection compares redis
+      # connection kwargs against a literal; redis-py 8.1 (current nixpkgs) adds
+      # `himport_registry`, so the assertion fails. Test-only.
+      rq_1 = pyPrev.rq_1.overridePythonAttrs (old: {
+        disabledTests = old.disabledTests ++ [ "test_parse_connection" ];
+      });
+    })
+  ];
+}