From a47a96e04144af21b425d29c1ce6f57593abea5e Mon Sep 17 00:00:00 2001
From: Phil Curzon <phil@novelfs.org>
Date: Wed, 1 Feb 2023 23:56:53 +0000
Subject: [PATCH] Treat null values as falsey in inverted sections

---
 CHANGELOG.md                | 4 ++++
 package.yaml                | 2 +-
 src/Text/Mustache/Render.hs | 1 +
 test/unit/Spec.hs           | 6 ++++++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e6c726f..5994b32 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Mustache library changelog
 
+## v2.4.1
+
+- Also treat Null as falsey in inverted sections
+
 ## v2.4.0
 
 - Support for aeson 2
diff --git a/package.yaml b/package.yaml
index c876834..d8e2f48 100644
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name: mustache
-version: '2.4.0'
+version: '2.4.1'
 synopsis: A mustache template parser library.
 description: ! 'Allows parsing and rendering template files with mustache markup.
   See the
diff --git a/src/Text/Mustache/Render.hs b/src/Text/Mustache/Render.hs
index 13c6458..7a0ad89 100644
--- a/src/Text/Mustache/Render.hs
+++ b/src/Text/Mustache/Render.hs
@@ -154,6 +154,7 @@ substituteNode (InvertedSection (NamedData secName) invSecSTree) =
   search secName >>= \case
     Just (Bool False) -> contents
     Just (Array a)    | V.null a -> contents
+    Just Null         -> contents
     Nothing           -> contents
     _                 -> return ()
   where
diff --git a/test/unit/Spec.hs b/test/unit/Spec.hs
index 04555ed..33263a2 100644
--- a/test/unit/Spec.hs
+++ b/test/unit/Spec.hs
@@ -161,6 +161,12 @@ substituteSpec =
           ])
       `shouldBe` "var1var2"
 
+    it "substitutes an inverse section when the key is present (and null)" $
+      substitute
+        (toTemplate [InvertedSection (NamedData ["section"]) [TextBlock "t"]])
+        (object ["section" ~> Null])
+      `shouldBe` "t"
+
     it "does not substitute a section when the key is not present" $
       substitute
         (toTemplate [Section (NamedData ["section"]) [TextBlock "t"]])