dt-schema, python3.pkgs.dtschema: handle jsonschema incompatibility

1. dt-schema is an application, so it can pin jsonschema to 4.17
2. mark python3.pkgs.dtschema broken with jsonschema > 4.17
3. mark python3.pkgs.dtschema broken on darwin

pkgs/development/python-modules/dtschema/default.nix

···
-{ lib
+{ stdenv
+, lib
 , buildPythonPackage
 , fetchFromGitHub
 , jsonschema
···
     changelog = "https://github.com/devicetree-org/dt-schema/releases/tag/v${version}";
     license = with licenses; [ bsd2 /* or */ gpl2Only ];
     maintainers = with maintainers; [ sorki ];
+
+    broken = (
+      # Library not loaded: @rpath/libfdt.1.dylib
+      stdenv.isDarwin ||
+
+      # see https://github.com/devicetree-org/dt-schema/issues/108
+      versionAtLeast jsonschema.version "4.18"
+    );
   };
 }
 

pkgs/development/tools/dt-schema/default.nix

···
+{ lib
+, python3
+}:
+
+let python = python3.override {
+  packageOverrides = self: super: {
+    # see https://github.com/devicetree-org/dt-schema/issues/108
+    jsonschema = super.jsonschema.overridePythonAttrs (old: rec {
+      version = "4.17.3";
+      disabled = self.pythonOlder "3.7";
+
+      src = old.src.override {
+        inherit version;
+        hash = "sha256-D4ZEN6uLYHa6ZwdFPvj5imoNUSqA6T+KvbZ29zfstg0=";
+      };
+
+      propagatedBuildInputs = with self; ([
+        attrs
+        pyrsistent
+      ] ++ lib.optionals (pythonOlder "3.8") [
+        importlib-metadata
+        typing-extensions
+      ] ++ lib.optionals (pythonOlder "3.9") [
+        importlib-resources
+        pkgutil-resolve-name
+      ]);
+    });
+  };
+}; in python.pkgs.toPythonApplication python.pkgs.dtschema
+

pkgs/top-level/all-packages.nix

···
 
   dtc = callPackage ../development/compilers/dtc { };
 
-  dt-schema = with python3Packages; toPythonApplication dtschema;
+  dt-schema = callPackage ../development/tools/dt-schema { };
 
   dub = callPackage ../development/tools/build-managers/dub { };