From f95fd57aaccb999b6fefe7b2ac9239a6c3325b0f Mon Sep 17 00:00:00 2001
From: acclassic <84147355+acclassic@users.noreply.github.com>
Date: Mon, 2 Jan 2023 17:35:08 +0100
Subject: [PATCH] tpl/compare: Sort special float values as string

When sorting strings a worng order is returned. This happens because the strings are first converted
to floating values to check whether or not they should be sorted as
floating values. When an error is returned the strings will be
handled as string literals.
No error will be returned when parsing Inf, Infinity or NaN (case insensitive) because they
will be coverted to special floating point values and therefore are
legal float values.
Now we check if the returned converted values are special floating
values and treat them as string literals.

Fixes #10389
---
 .gitignore                  | 29 -----------------------------
 tpl/compare/compare.go      |  7 +++++--
 tpl/compare/compare_test.go |  2 ++
 3 files changed, 7 insertions(+), 31 deletions(-)
 delete mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
deleted file mode 100644
index b2aeb9142..000000000
--- a/.gitignore
+++ /dev/null
@@ -1,29 +0,0 @@
-/hugo
-docs/public*
-/.idea
-.vscode/*
-hugo.exe
-*.test
-*.prof
-nohup.out
-cover.out
-*.swp
-*.swo
-.DS_Store
-*~
-vendor/*/
-*.bench
-*.debug
-coverage*.out
-
-dock.sh
-
-GoBuilds
-dist
-
-hugolib/hugo_stats.json
-resources/sunset.jpg
-
-vendor
-
-.hugo_build.lock
diff --git a/tpl/compare/compare.go b/tpl/compare/compare.go
index 47f77cc99..2ef5aacfe 100644
--- a/tpl/compare/compare.go
+++ b/tpl/compare/compare.go
@@ -16,6 +16,7 @@ package compare
 
 import (
 	"fmt"
+	"math"
 	"reflect"
 	"strconv"
 	"time"
@@ -273,7 +274,8 @@ func (ns *Namespace) compareGetWithCollator(collator *langs.Collator, a any, b a
 	case reflect.String:
 		var err error
 		left, err = strconv.ParseFloat(av.String(), 64)
-		if err != nil {
+		// Check if float is a special floating value and cast value as string.
+		if math.IsInf(left, 0) || math.IsNaN(left) || err != nil {
 			str := av.String()
 			leftStr = &str
 		}
@@ -300,7 +302,8 @@ func (ns *Namespace) compareGetWithCollator(collator *langs.Collator, a any, b a
 	case reflect.String:
 		var err error
 		right, err = strconv.ParseFloat(bv.String(), 64)
-		if err != nil {
+		// Check if float is a special floating value and cast value as string.
+		if math.IsInf(right, 0) || math.IsNaN(right) || err != nil {
 			str := bv.String()
 			rightStr = &str
 		}
diff --git a/tpl/compare/compare_test.go b/tpl/compare/compare_test.go
index ce2016b38..4c50f5f0f 100644
--- a/tpl/compare/compare_test.go
+++ b/tpl/compare/compare_test.go
@@ -217,6 +217,8 @@ func doTestCompare(t *testing.T, tp tstCompareType, funcUnderTest func(a, b any)
 		{"a", "a", 0},
 		{"a", "b", -1},
 		{"b", "a", 1},
+		{"infinity", "infinity", 0},
+		{"nan", "nan", 0},
 		{tstEqerType1("a"), tstEqerType1("a"), 0},
 		{tstEqerType1("a"), tstEqerType2("a"), 0},
 		{tstEqerType2("a"), tstEqerType1("a"), 0},