From 8b6b2e52530117ba4196967c0c9cc6a596460498 Mon Sep 17 00:00:00 2001
From: traxys <quentin+dev@familleboyer.net>
Date: Wed, 3 Jul 2024 17:34:31 +0200
Subject: [PATCH] dev: Add a script to generate rust-analyzer options

---
 flake-modules/default.nix                 |   1 +
 flake-modules/updates/default.nix         |   9 +
 flake-modules/updates/rust-analyzer.nix   | 195 ++++++++++++++++++++++
 plugins/lsp/language-servers/update_ra.md |  13 --
 4 files changed, 205 insertions(+), 13 deletions(-)
 create mode 100644 flake-modules/updates/default.nix
 create mode 100644 flake-modules/updates/rust-analyzer.nix
 delete mode 100644 plugins/lsp/language-servers/update_ra.md

diff --git a/flake-modules/default.nix b/flake-modules/default.nix
index 59c16d98..dd88406e 100644
--- a/flake-modules/default.nix
+++ b/flake-modules/default.nix
@@ -10,6 +10,7 @@
     ./templates.nix
     ./tests.nix
     ./wrappers.nix
+    ./updates
   ];
 
   perSystem =
diff --git a/flake-modules/updates/default.nix b/flake-modules/updates/default.nix
new file mode 100644
index 00000000..900c3513
--- /dev/null
+++ b/flake-modules/updates/default.nix
@@ -0,0 +1,9 @@
+{
+  perSystem =
+    { pkgs, ... }:
+    {
+      packages = {
+        rust-analyzer-options = pkgs.callPackage ./rust-analyzer.nix { };
+      };
+    };
+}
diff --git a/flake-modules/updates/rust-analyzer.nix b/flake-modules/updates/rust-analyzer.nix
new file mode 100644
index 00000000..fcad2fbd
--- /dev/null
+++ b/flake-modules/updates/rust-analyzer.nix
@@ -0,0 +1,195 @@
+#
+# This derivation creates a Nix file that describes the Nix module that needs to be instantiated
+#
+# The create file is of the form:
+# 
+# {
+#   "<rust-analyzer.option.name>" = {
+#      description = "<option description>";
+#      type = {
+#          kind = "<name of the type>";
+#          # Other values depending on the kind, like values for enum or subTypes for oneOf
+#      };
+#   };
+# }
+#
+{
+  lib,
+  rust-analyzer,
+  writeText,
+}:
+let
+  packageJSON = "${rust-analyzer.src}/editors/code/package.json";
+  options = (lib.importJSON packageJSON).contributes.configuration;
+
+  generatedStart = lib.lists.findFirstIndex (
+    e: e == { title = "$generated-start"; }
+  ) (throw "missing generated start") options;
+  generatedEnd = lib.lists.findFirstIndex (
+    e: e == { title = "$generated-end"; }
+  ) (throw "missing generated end") options;
+
+  # Extract only the generated properties, removing vscode specific options
+  rustAnalyzerProperties = lib.lists.sublist (generatedStart + 1) (
+    generatedEnd - generatedStart - 1
+  ) options;
+
+  mkRustAnalyzerOptionType =
+    nullable: property_name:
+    {
+      type,
+      enum ? null,
+      minimum ? null,
+      maximum ? null,
+      items ? null,
+      anyOf ? null,
+      # Not used in the function, but anyOf values contain it
+      enumDescriptions ? null,
+    }@property:
+    if enum != null then
+      {
+        kind = "enum";
+        values = enum;
+      }
+    else if anyOf != null then
+      let
+        possibleTypes = lib.filter (sub: !(sub.type == "null" && nullable)) anyOf;
+      in
+      {
+        kind = "oneOf";
+        subTypes = builtins.map (
+          t: mkRustAnalyzerOptionType nullable "${property_name}-sub" t
+        ) possibleTypes;
+      }
+    else if lib.isList type then
+      (
+        if lib.head type == "null" then
+          assert lib.assertMsg (
+            lib.length type == 2
+          ) "Lists starting with null are assumed to mean nullOr, so length 2";
+          let
+            innerType = property // {
+              type = lib.elemAt type 1;
+            };
+            inner = mkRustAnalyzerOptionType nullable "${property_name}-inner" innerType;
+          in
+          assert lib.assertMsg nullable "nullOr types are not yet handled";
+          inner
+        else
+          let
+            innerTypes = builtins.map (
+              t: mkRustAnalyzerOptionType nullable "${property_name}-inner" (property // { type = t; })
+            ) type;
+          in
+          {
+            kind = "oneOf";
+            subTypes = innerTypes;
+          }
+      )
+    else if type == "array" then
+      {
+        kind = "list";
+        item = mkRustAnalyzerOptionType false "${property_name}-item" items;
+      }
+    else if type == "number" || type == "integer" then
+      {
+        kind = type;
+        inherit minimum maximum;
+      }
+    else if
+      lib.elem type [
+        "object"
+        "string"
+        "boolean"
+      ]
+    then
+      { kind = type; }
+    else
+      throw "Unhandled value in ${property_name}: ${lib.generators.toPretty { } property}";
+
+  mkRustAnalyzerOption =
+    property_name:
+    {
+      # List all possible values so that we are sure no new values are introduced
+      default,
+      markdownDescription,
+      enum ? null,
+      enumDescriptions ? null,
+      anyOf ? null,
+      minimum ? null,
+      maximum ? null,
+      items ? null,
+      # TODO: add this in the documentation ?
+      uniqueItems ? null,
+      type ? null,
+    }:
+    let
+      enumDesc =
+        values: descriptions:
+        let
+          valueDesc = builtins.map ({ fst, snd }: ''- ${fst}: ${snd}'') (
+            lib.lists.zipLists values descriptions
+          );
+        in
+        ''
+          ${markdownDescription}
+
+          Values:
+          ${builtins.concatStringsSep "\n" valueDesc}
+        '';
+    in
+    {
+      type = mkRustAnalyzerOptionType true property_name {
+        inherit
+          type
+          enum
+          minimum
+          maximum
+          items
+          anyOf
+          enumDescriptions
+          ;
+      };
+      pluginDefault = default;
+      description =
+        if
+          enum == null && (anyOf == null || builtins.all (subProp: !(lib.hasAttr "enum" subProp)) anyOf)
+        then
+          ''
+            ${markdownDescription}
+          ''
+        else if enum != null then
+          assert lib.assertMsg (anyOf == null) "enum + anyOf types are not yet handled";
+          enumDesc enum enumDescriptions
+        else
+          let
+            subEnums = lib.filter (lib.hasAttr "enum") anyOf;
+            subEnum =
+              assert lib.assertMsg (
+                lib.length subEnums == 1
+              ) "anyOf types may currently only contain a single enum";
+              lib.head subEnums;
+          in
+          enumDesc subEnum.enum subEnum.enumDescriptions;
+    };
+
+  rustAnalyzerOptions = builtins.map (
+    v:
+    let
+      props = lib.attrsToList v.properties;
+      prop =
+        assert lib.assertMsg (
+          lib.length props == 1
+        ) "Rust analyzer configuration items are only supported with a single element";
+        lib.head props;
+    in
+    {
+      "${prop.name}" = mkRustAnalyzerOption prop.name prop.value;
+    }
+  ) rustAnalyzerProperties;
+in
+writeText "rust-analyzer-options.nix" (
+  "# WARNING: DO NOT EDIT\n"
+  + "# This file is generated with packages.<system>.rust-analyzer-options, which is run automatically by CI\n"
+  + (lib.generators.toPretty { } (lib.mergeAttrsList rustAnalyzerOptions))
+)
diff --git a/plugins/lsp/language-servers/update_ra.md b/plugins/lsp/language-servers/update_ra.md
deleted file mode 100644
index 684a32dd..00000000
--- a/plugins/lsp/language-servers/update_ra.md
+++ /dev/null
@@ -1,13 +0,0 @@
-# Updating rust-analyzer options
-
-Because there a large number of rust-analyzer options it's difficult to handle them by hand.
-
-The options can be fetched from the [rust-analyzer package.json](https://github.com/rust-lang/rust-analyzer/blob/master/editors/code/package.json).
-
-There is a derivation on the top-level flake that allows to build it easily, you just have to run:
-
-```bash
-nix build .#rustAnalyzerOptions
-```
-
-You can then copy the `result/share/rust-analyzer-config.nix` to the correct location.