fix data helper's WriteJsonFile not deleting file if data is null (#799)

2 files changed, 6 insertions, 2 deletions

diff --git a/src/SMAPI/Framework/ModHelpers/DataHelper.cs b/src/SMAPI/Framework/ModHelpers/DataHelper.cs
index 0fe3209f..4cbfd73f 100644
--- a/src/SMAPI/Framework/ModHelpers/DataHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/DataHelper.cs
@@ -58,7 +58,11 @@ namespace StardewModdingAPI.Framework.ModHelpers
                 throw new InvalidOperationException($"You must call {nameof(IMod.Helper)}.{nameof(IModHelper.Data)}.{nameof(this.WriteJsonFile)} with a relative path (without directory climbing).");
 
             path = Path.Combine(this.ModFolderPath, PathUtilities.NormalizePath(path));
-            this.JsonHelper.WriteJsonFile(path, data);
+
+            if (data != null)
+                this.JsonHelper.WriteJsonFile(path, data);
+            else
+                File.Delete(path);
         }
 
         /****
diff --git a/src/SMAPI/IDataHelper.cs b/src/SMAPI/IDataHelper.cs
index 4922c8da..901266d7 100644
--- a/src/SMAPI/IDataHelper.cs
+++ b/src/SMAPI/IDataHelper.cs
@@ -21,7 +21,7 @@ namespace StardewModdingAPI
         /// <summary>Save data to a JSON file in the mod's folder.</summary>
         /// <typeparam name="TModel">The model type. This should be a plain class that has public properties for the data you want. The properties can be complex types.</typeparam>
         /// <param name="path">The file path relative to the mod folder.</param>
-        /// <param name="data">The arbitrary data to save.</param>
+        /// <param name="data">The arbitrary data to save, or <c>null</c> to delete the file.</param>
         /// <exception cref="InvalidOperationException">The <paramref name="path"/> is not relative or contains directory climbing (../).</exception>
         void WriteJsonFile<TModel>(string path, TModel data) where TModel : class;