From 20a9a21b246ca684e4e5a45e543a8a53be46e1d2 Mon Sep 17 00:00:00 2001
From: Yarny0 <41838844+Yarny0@users.noreply.github.com>
Date: Wed, 23 Aug 2023 21:29:29 +0200
Subject: [PATCH] nixos/tsm-client: add migration code for freeform settings

To help users migrate from the previous
settings to new freeform settings type,
the commit at hand adds some
`mkRemovedOptionModule` and `mkRenamedOptionModule`.

These modules are not designed to work
inside an attribute set of submodules.
They create values for `assertions` and
`warnings` to inform the user of required changes.
Also, these informational texts do not contain
the full attribute path of the changed options.
To work around these deficiencies,
we define the required options `assertions` and `warnings`
inside the submodule and later add the values collected
inside these options to the corresponding top-level options.
In the course of doing so, we also add the full attribute path
to the informational texts so the user knows these warning
and error messages refer to the `tsmClient.servers` option.

Also, we have to filter out `warnings`, `assertions`, and
the "old" options when rendering the target config file.
---
 nixos/modules/programs/tsm-client.nix | 36 ++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/nixos/modules/programs/tsm-client.nix b/nixos/modules/programs/tsm-client.nix
index 03dc50eea801..45d436221ee3 100644
--- a/nixos/modules/programs/tsm-client.nix
+++ b/nixos/modules/programs/tsm-client.nix
@@ -1,4 +1,5 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:  # XXX migration code for freeform settings: `options` can be removed in 2025
+let optionsGlobal = options; in
 
 let
 
@@ -95,6 +96,19 @@ let
     };
     config.commmethod = mkDefault "v6tcpip";  # uses v4 or v6, based on dns lookup result
     config.passwordaccess = if config.genPasswd then "generate" else "prompt";
+    # XXX migration code for freeform settings, these can be removed in 2025:
+    options.warnings = optionsGlobal.warnings;
+    options.assertions = optionsGlobal.assertions;
+    imports = let inherit (lib.modules) mkRemovedOptionModule mkRenamedOptionModule; in [
+      (mkRemovedOptionModule [ "extraConfig" ] "Please just add options directly to the server attribute set, cf. the description of `programs.tsmClient.servers`.")
+      (mkRemovedOptionModule [ "text" ] "Please just add options directly to the server attribute set, cf. the description of `programs.tsmClient.servers`.")
+      (mkRenamedOptionModule [ "name" ] [ "servername" ])
+      (mkRenamedOptionModule [ "server" ] [ "tcpserveraddress" ])
+      (mkRenamedOptionModule [ "port" ] [ "tcpport" ])
+      (mkRenamedOptionModule [ "node" ] [ "nodename" ])
+      (mkRenamedOptionModule [ "passwdDir" ] [ "passworddir" ])
+      (mkRenamedOptionModule [ "includeExclude" ] [ "inclexcl" ])
+    ];
   };
 
   options.programs.tsmClient = {
@@ -209,7 +223,9 @@ let
         contain duplicate names
         (note that setting names are case insensitive).
       '';
-    }) cfg.servers);
+    }) cfg.servers)
+    # XXX migration code for freeform settings, this can be removed in 2025:
+    ++ (enrichMigrationInfos "assertions" (addText: { assertion, message }: { inherit assertion; message = addText message; }));
 
   makeDsmSysLines = key: value:
     # Turn a key-value pair from the server options attrset
@@ -228,7 +244,12 @@ let
   makeDsmSysStanza = {servername, ... }@serverCfg:
     let
       # drop special values that should not go into server config block
-      attrs = removeAttrs serverCfg [ "servername" "genPasswd" ];
+      attrs = removeAttrs serverCfg [ "servername" "genPasswd"
+        # XXX migration code for freeform settings, these can be removed in 2025:
+        "assertions" "warnings"
+        "extraConfig" "text"
+        "name" "server" "port" "node" "passwdDir" "includeExclude"
+      ];
     in
       ''
         servername  ${servername}
@@ -246,6 +267,13 @@ let
     ${concatLines (map makeDsmSysStanza (attrValues cfg.servers))}
   '';
 
+  # XXX migration code for freeform settings, this can be removed in 2025:
+  enrichMigrationInfos = what: how: concatLists (
+    mapAttrsToList
+    (name: serverCfg: map (how (text: "In `programs.tsmClient.servers.${name}`: ${text}")) serverCfg."${what}")
+    cfg.servers
+  );
+
 in
 
 {
@@ -260,6 +288,8 @@ in
       dsmSysApi = dsmSysCli;
     };
     environment.systemPackages = [ cfg.wrappedPackage ];
+    # XXX migration code for freeform settings, this can be removed in 2025:
+    warnings = enrichMigrationInfos "warnings" (addText: addText);
   };
 
   meta.maintainers = [ lib.maintainers.yarny ];