Add support for additional replacement characers

Author: kdumontnu

models/user/user.go

@@ -523,20 +523,21 @@ func GetUserSalt() (string, error) {
 // Note: The set of characters here can safely expand without a breaking change,
 // but characters removed from this set can cause user account linking to break
 var (
-	removeCharsRE             = regexp.MustCompile(`['\x60]`)
+	customCharsReplacement    = strings.NewReplacer("Æ", "AE")
+	removeCharsRE             = regexp.MustCompile(`['´\x60]`)
 	removeDiacriticsTransform = transform.Chain(norm.NFD, runes.Remove(runes.In(unicode.Mn)), norm.NFC)
-	replaceCharsRE            = regexp.MustCompile(`[\s,]`)
+	replaceCharsHyphenRE      = regexp.MustCompile(`[\s~+]`)
 )
 
 // normalizeUserName returns a string with single-quotes and diacritics
 // removed, and any other non-supported username characters replaced with
 // a `-` character
 func NormalizeUserName(s string) (string, error) {
-	strDiacriticsRemoved, n, err := transform.String(removeDiacriticsTransform, s)
+	strDiacriticsRemoved, n, err := transform.String(removeDiacriticsTransform, customCharsReplacement.Replace(s))
 	if err != nil {
 		return "", fmt.Errorf("Failed to normalize character `%v` in provided username `%v`", s[n], s)
 	}
-	return replaceCharsRE.ReplaceAllLiteralString(removeCharsRE.ReplaceAllLiteralString(strDiacriticsRemoved, ""), "-"), nil
+	return replaceCharsHyphenRE.ReplaceAllLiteralString(removeCharsRE.ReplaceAllLiteralString(strDiacriticsRemoved, ""), "-"), nil
 }
 
 var (

models/user/user_test.go

@@ -553,13 +553,13 @@ func Test_NormalizeUserFromEmail(t *testing.T) {
 	}{
 		{"test", "test", true},
 		{"Sinéad.O'Connor", "Sinead.OConnor", true},
-		{"Æsir", "Æsir", false}, // Currently unsupported
+		{"Æsir", "AEsir", true},
 		// \u00e9\u0065\u0301
 		{"éé", "ee", true},
 		{"Awareness Hub", "Awareness-Hub", true},
 		{"double__underscore", "double__underscore", false}, // We should consider squashing double non-alpha characters
 		{".bad.", ".bad.", false},
-		{"new😀user", "new😀user", false},
+		{"new😀user", "new😀user", false}, // No plans to support
 	}
 	for _, testCase := range testCases {
 		normalizedName, err := user_model.NormalizeUserName(testCase.Input)