From 21ed4e6246a0b3406ca3badbb392d03074c5b3d6 Mon Sep 17 00:00:00 2001
From: Chris Martin <ch.martin@gmail.com>
Date: Tue, 7 Feb 2023 14:15:37 -0700
Subject: [PATCH] Modify mappend to avoid discarding

Closes #2
---
 CHANGELOG.md    | 17 +++++++++++++++++
 ini.cabal       |  2 +-
 src/Data/Ini.hs |  7 ++++++-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3b4aa4..f4e5843 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,20 @@
+## 0.5.0
+
+_2023-02-08, Chris Martin_
+
+The behavior of `(<>)` for the `Ini` type has changed
+[#2](https://github.com/andreasabel/ini/issues/2)
+
+- `<>` previously discarded all `iniGlobals`. Now it concatenates
+  the globals from the two `Ini` values.
+
+- When two `Ini` values contained `iniSections` with the same name,
+  `<>` previously returned the section from the left value and
+  discarded the section of the same name from the right value.
+  Now it concatenates the sections of the same name.
+
+Tested with GHC 7.0 - ghc-9.6.0.20230128.
+
 ## 0.4.2
 
 _2022-07-26, Andreas Abel_
diff --git a/ini.cabal b/ini.cabal
index 1ec9bcb..3193daf 100644
--- a/ini.cabal
+++ b/ini.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >= 1.10
 name:                ini
-version:             0.4.2
+version:             0.5.0
 synopsis:            Configuration files in the INI format.
 description:         Quick and easy configuration files in the INI format.
 license:             BSD3
diff --git a/src/Data/Ini.hs b/src/Data/Ini.hs
index f3201c7..ef3f237 100644
--- a/src/Data/Ini.hs
+++ b/src/Data/Ini.hs
@@ -89,8 +89,13 @@ data Ini =
     }
   deriving (Show, Eq)
 
+-- | '<>' concatenates the lists of entries within each section (since @ini-0.5.0@)
 instance Semigroup Ini where
-  x <> y = Ini {iniGlobals = mempty, iniSections = iniSections x <> iniSections y}
+  x <> y =
+    Ini
+      { iniGlobals = iniGlobals x ++ iniGlobals y
+      , iniSections = M.unionWith (++) (iniSections x) (iniSections y)
+      }
 
 instance Monoid Ini where
   mempty = Ini {iniGlobals = mempty, iniSections = mempty}