Add functions for CVar stream validation to ConfigurationManager.

Robust.Shared/Configuration/ConfigurationManager.cs

@@ -74,6 +74,24 @@ public HashSet<string> LoadFromTomlStream(Stream file)
             return LoadFromTomlTable(tblRoot);
         }
 
+        /// <inheritdoc />
+        public HashSet<string> ValidateTomlStream(Stream file)
+        {
+            TomlTable tblRoot;
+            try
+            {
+                tblRoot = Toml.ReadStream(file);
+            }
+            catch (Exception e)
+            {
+                _sawmill.Error("Unable to load configuration from table:\n{0}", e);
+                return [];
+            }
+
+            return ValidateTomlTable(tblRoot);
+        }
+
+        /// <inheritdoc />
         private HashSet<string> LoadFromTomlTable(TomlTable table)
         {
             var loaded = new HashSet<string>();
@@ -98,6 +116,17 @@ private HashSet<string> LoadFromTomlTable(TomlTable table)
             return loaded;
         }
 
+        /// <inheritdoc />
+        private HashSet<string> ValidateTomlTable(TomlTable table)
+        {
+            var loaded = new HashSet<string>();
+
+            foreach (var (cvar, _) in ParseCVarValuesFromToml(table))
+                loaded.Add(cvar);
+
+            return loaded;
+        }
+
         private void RunDeferredInvokeCallbacks(in ValueList<ValueChangedInvoke> callbackEvents)
         {
             foreach (var callback in callbackEvents)

Robust.Shared/Configuration/IConfigurationManager.cs

@@ -69,8 +69,24 @@ public interface IConfigurationManager
         /// </summary>
         void SaveToTomlStream(Stream stream, IEnumerable<string> cvars);
 
+        /// <summary>
+        /// Load a TOML config file, using all CVar values specified inside.
+        /// </summary>
+        /// <remarks>
+        /// All CVars in the TOML file must be registered when this function is called.
+        /// </remarks>
+        /// <returns>A set of all CVars touched.</returns>
         HashSet<string> LoadFromTomlStream(Stream stream);
 
+        /// <summary>
+        /// Load a TOML config file and try and parse its contents without side-effects.
+        /// </summary>
+        /// <remarks>
+        /// All CVars in the TOML file must be registered when this function is called.
+        /// </remarks>
+        /// <returns>A set of all CVars that would be touched by this stream.</returns>
+        HashSet<string> ValidateTomlStream(Stream stream);
+
         /// <summary>
         /// Load a TOML config file and use the CVar values specified as an <see cref="OverrideDefault"/>.
         /// </summary>