From 57545fdb02e7c82228a592d7965b1a0b23b1a91a Mon Sep 17 00:00:00 2001
From: Eric Ahlberg <eahlberg@gmail.com>
Date: Wed, 11 May 2022 16:19:42 +0200
Subject: [PATCH] Do not filter out parameters with the same name in pagination
 links

---
 src/Yesod/Paginator/Widgets.hs      | 10 ++++++----
 test/Yesod/Paginator/WidgetsSpec.hs | 24 +++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/src/Yesod/Paginator/Widgets.hs b/src/Yesod/Paginator/Widgets.hs
index 7c97088..4003a3f 100644
--- a/src/Yesod/Paginator/Widgets.hs
+++ b/src/Yesod/Paginator/Widgets.hs
@@ -178,10 +178,12 @@ getUpdateGetParams
 getUpdateGetParams pageParamName = do
     params <- handlerToWidget $ reqGetParams <$> getRequest
     pure
-        $ \number ->
-              nubOn fst
-                  $ [(unPageParamName pageParamName, tshow number)]
-                  <> params
+        $ \number -> formatParams number params
+  where
+    formatParams :: Show a => a -> [(Text, Text)] -> [(Text, Text)]
+    formatParams number params =
+      let name = unPageParamName pageParamName
+      in [(name, tshow number)] <> filter ((/=) name . fst) params
 
 renderGetParams :: [(Text, Text)] -> Text
 renderGetParams [] = ""
diff --git a/test/Yesod/Paginator/WidgetsSpec.hs b/test/Yesod/Paginator/WidgetsSpec.hs
index e8afb6f..9b27ba6 100644
--- a/test/Yesod/Paginator/WidgetsSpec.hs
+++ b/test/Yesod/Paginator/WidgetsSpec.hs
@@ -8,7 +8,8 @@ import SpecHelper
 
 spec :: Spec
 spec = withApp $ do
-    describe "simple" $ it "works" $ do
+    describe "simple" $ do
+      it "works" $ do
         get $ SimpleR 10 3 3
 
         statusIs 200
@@ -52,6 +53,27 @@ spec = withApp $ do
             , "</ul>"
             ]
 
+      it "includes all parameters with the same name" $ do
+        get $ SimpleR 10 3 3
+
+        request $ do
+            addGetParam "p" "3"
+            addGetParam "ids[]" "1"
+            addGetParam "ids[]" "2"
+            setUrl $ SimpleR 10 3 3
+
+        statusIs 200
+
+        bodyContains $ concat
+            [ "<ul class=\"pagination\">"
+            , "<li class=\"prev\"><a href=\"?p=2&amp;ids%5B%5D=2&amp;ids%5B%5D=1\">«</a></li>"
+            , "<li class=\"prev\"><a href=\"?p=2&amp;ids%5B%5D=2&amp;ids%5B%5D=1\">2</a></li>"
+            , "<li class=\"active disabled\"><a>3</a></li>"
+            , "<li class=\"next\"><a href=\"?p=4&amp;ids%5B%5D=2&amp;ids%5B%5D=1\">4</a></li>"
+            , "<li class=\"next\"><a href=\"?p=4&amp;ids%5B%5D=2&amp;ids%5B%5D=1\">»</a></li>"
+            , "</ul>"
+            ]
+
     describe "ellipsed" $ it "works" $ do
         get $ EllipsedR 10 3 3