feat(config): health check reports for .vscode/settings.json

lua/rustaceanvim/config/json.lua

@@ -1,10 +1,37 @@
 local M = {}
 
-local function tbl_set(tbl, keys, value)
+local warnings = {}
+local errors = {}
+local is_json_config_loaded = false
+
+---@param warning string
+local function add_warning(warning)
+  table.insert(warnings, warning)
+end
+
+---@param err string
+local function add_error(err)
+  table.insert(errors, err)
+end
+
+---@param field_name string | nil
+---@param tbl unknown
+---@param keys string[]
+---@param value unknown
+local function tbl_set(field_name, tbl, keys, value)
   local next = table.remove(keys, 1)
+  if type(tbl) ~= 'table' then
+    add_warning(([[
+Ignored field '%s' of invalid type '%s': %s
+Please refer to the rust-analyzer documentation at
+https://rust-analyzer.github.io/manual.html#%s
+]]):format(field_name, type(value), vim.inspect(value), field_name))
+    return
+  end
   if #keys > 0 then
     tbl[next] = tbl[next] or {}
-    tbl_set(tbl[next], keys, value)
+    field_name = (field_name and field_name .. '.' or '') .. next
+    tbl_set(field_name, tbl[next], keys, value)
   else
     tbl[next] = value
   end
@@ -15,14 +42,17 @@ end
 ---@param json_value unknown
 local function override_tbl_values(tbl, json_key, json_value)
   local keys = vim.split(json_key, '%.')
-  tbl_set(tbl, keys, json_value)
+  tbl_set(nil, tbl, keys, json_value)
 end
 
 ---@param json_content string
 ---@return table
 function M.silent_decode(json_content)
+  warnings = {}
+  errors = {}
   local ok, json_tbl = pcall(vim.json.decode, json_content)
   if not ok or type(json_tbl) ~= 'table' then
+    add_error(('Failed to decode json: %s'):format(json_tbl or 'unknown error'))
     return {}
   end
   return json_tbl
@@ -32,6 +62,7 @@ end
 ---@param json_tbl { [string]: unknown }
 ---@param key_predicate? fun(string): boolean
 function M.override_with_json_keys(tbl, json_tbl, key_predicate)
+  is_json_config_loaded = true
   for json_key, value in pairs(json_tbl) do
     if not key_predicate or key_predicate(json_key) then
       override_tbl_values(tbl, json_key, value)
@@ -47,4 +78,16 @@ function M.override_with_rust_analyzer_json_keys(tbl, json_tbl)
   end)
 end
 
+function M.is_json_config_loaded()
+  return is_json_config_loaded
+end
+
+function M.get_warnings()
+  return warnings
+end
+
+function M.get_errors()
+  return errors
+end
+
 return M

lua/rustaceanvim/health.lua

@@ -148,6 +148,25 @@ local function check_tree_sitter()
   end
 end
 
+local function check_json_config()
+  local json = require('rustaceanvim.config.json')
+  if json.is_json_config_loaded() then
+    local errors = json.get_errors()
+    if #errors > 0 then
+      h.warn('.vscode/settings.json failed to load.')
+      vim.iter(errors):each(h.error)
+      return
+    end
+    local warnings = json.get_warnings()
+    if #warnings == 0 then
+      h.ok('.vscode/settings.json loaded without errors.')
+    else
+      h.warn('.vscode/settings.json loaded with warnings.')
+      vim.iter(warnings):each(h.warn)
+    end
+  end
+end
+
 function health.check()
   local types = require('rustaceanvim.types.internal')
   local config = require('rustaceanvim.config.internal')
@@ -281,6 +300,7 @@ function health.check()
   check_config(config)
   check_for_conflicts()
   check_tree_sitter()
+  check_json_config()
 end
 
 return health

spec/json_spec.lua

@@ -42,4 +42,47 @@ describe('Decode rust-analyzer settings from json', function()
       },
     }, tbl)
   end)
+  it('persists warnings on invalid config', function()
+    local invalid_json_content = [[
+{
+	"rust-analyzer.checkOnSave.overrideCommand": [
+		"cargo",
+		"check",
+		"-p",
+		"service_b",
+		"--message-format=json"
+	],
+	"rust-analyzer.foo.enable": true,
+	"rust-analyzer.foo.bar.enable": true,
+	"rust-analyzer.foo.bar.baz.bat": "something deeply nested",
+	"some-other-key.foo.bar.baz.bat": "should not be included"
+}
+]]
+    local tbl = {
+      ['rust-analyzer'] = {
+        checkOnSave = true,
+      },
+    }
+    local json_tbl = json.silent_decode(invalid_json_content)
+    json.override_with_rust_analyzer_json_keys(tbl, json_tbl)
+    assert.same({
+      [[
+Ignored field 'rust-analyzer.checkOnSave' of invalid type 'table': { "cargo", "check", "-p", "service_b", "--message-format=json" }
+Please refer to the rust-analyzer documentation at
+https://rust-analyzer.github.io/manual.html#rust-analyzer.checkOnSave
+]],
+    }, json.get_warnings())
+  end)
+  it('persists warnings about config parse errors', function()
+    local unsupported_json_content = [[
+{
+  // This is a json5 comment
+	"rust-analyzer.foo.enable": true,
+}
+]]
+    json.silent_decode(unsupported_json_content)
+    assert.same({
+      'Failed to decode json: Expected object key string but found invalid token at character 5',
+    }, json.get_errors())
+  end)
 end)