Replaced relogin rejection with a notice and proper redirect.

public/style.css

@@ -9415,6 +9415,10 @@ span.icon-rss::before {
   background-color: #43a52f;
   background-color: var(--notice-success-color); }
 
+.notice-warn {
+  background-color: #aa7d30;
+  background-color: var(--notice-warn-color); }
+
 .notice-failure {
   background-color: #b42222;
   background-color: var(--notice-failure-color); }

public/themes/dark/theme.css

@@ -244,6 +244,7 @@ pre, code, .codeblock {
   --notice-lts-color: #2a681d;
   --notice-lts-reqd-color: #876327;
   --notice-success-color: #2a681d;
+  --notice-warn-color: #876327;
   --notice-failure-color: #7a2020;
   --optionbar-border-color: #333;
   --tab-background: #181818;

public/themes/light/theme.css

@@ -262,6 +262,7 @@ pre, code, .codeblock {
   --notice-lts-color: #43a52f;
   --notice-lts-reqd-color: #aa7d30;
   --notice-success-color: #43a52f;
+  --notice-warn-color: #aa7d30;
   --notice-failure-color: #b42222;
   --optionbar-border-color: #ccc;
   --tab-background: #fff;

src/rawdata/scss/_notices.scss

@@ -36,6 +36,10 @@
 	@include usevar(background-color, notice-success-color);
 }
 
+.notice-warn {
+	@include usevar(background-color, notice-warn-color);
+}
+
 .notice-failure {
 	@include usevar(background-color, notice-failure-color);
 }

src/rawdata/scss/themes/dark/_variables.scss

@@ -46,6 +46,7 @@ $vars: (
   notice-lts-color: #2a681d,
   notice-lts-reqd-color: #876327,
   notice-success-color: #2a681d,
+  notice-warn-color: #876327,
   notice-failure-color: #7a2020,
 
   optionbar-border-color: #333,

src/rawdata/scss/themes/light/_variables.scss

@@ -46,6 +46,7 @@ $vars: (
   notice-lts-color: #43a52f,
   notice-lts-reqd-color: #aa7d30,
   notice-success-color: #43a52f,
+  notice-warn-color: #aa7d30,
   notice-failure-color: #b42222,
 
   optionbar-border-color: #ccc,

src/website/auth.go

@@ -41,10 +41,6 @@ func LoginPage(c *RequestContext) ResponseData {
 }
 
 func Login(c *RequestContext) ResponseData {
-	if c.CurrentUser != nil {
-		return RejectRequest(c, "You are already logged in.")
-	}
-
 	form, err := c.GetFormValues()
 	if err != nil {
 		return c.ErrorResponse(http.StatusBadRequest, NewSafeError(err, "request must contain form data"))
@@ -55,6 +51,12 @@ func Login(c *RequestContext) ResponseData {
 		redirect = "/"
 	}
 
+	if c.CurrentUser != nil {
+		res := c.Redirect(redirect, http.StatusSeeOther)
+		res.AddFutureNotice("warn", fmt.Sprintf("You are already logged in as %s.", c.CurrentUser.Username))
+		return res
+	}
+
 	username := form.Get("username")
 	password := form.Get("password")
 	if username == "" || password == "" {