From 0c09bc24ffad9a662537c5cd94550ef0e14b36bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ana=C3=ABl=20Beutot?= <abeutot@oserror.org>
Date: Tue, 29 Dec 2020 21:45:39 +0100
Subject: [PATCH] Fix workspace assignements after output changes

Fix #4261

The previous method was modifying the same list it was iterating upon
causing an erronous iteration and thus not every workspace got assigned
back to were they should (only the first one).
---
 src/randr.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/src/randr.c b/src/randr.c
index 8e000ca6..b4d1d094 100644
--- a/src/randr.c
+++ b/src/randr.c
@@ -439,28 +439,31 @@ void init_ws_for_output(Output *output) {
     Con *previous_focus = con_get_workspace(focused);
 
     /* Iterate over all workspaces and check if any of them should be assigned
-     * to this output. */
-    Con *output_con;
-    TAILQ_FOREACH (output_con, &(croot->nodes_head), nodes) {
-        if (con_is_internal(output_con)) {
+     * to this output.
+     * Note: in order to do that we iterate over all_cons and not using another
+     * list that would be updated during iteration by the
+     * workspace_move_to_output function. */
+    Con *workspace;
+    TAILQ_FOREACH (workspace, &all_cons, all_cons) {
+        if (workspace->type != CT_WORKSPACE || con_is_internal(workspace)) {
             continue;
         }
 
-        Con *workspace;
-        TAILQ_FOREACH (workspace, &(output_get_content(output_con)->nodes_head), nodes) {
-            Con *workspace_out = get_assigned_output(workspace->name, workspace->num);
-            if (output->con != workspace_out) {
-                continue;
-            }
+        Con *workspace_out = get_assigned_output(workspace->name, workspace->num);
 
-            DLOG("Moving workspace \"%s\" from output \"%s\" to \"%s\" due to assignment\n",
-                 workspace->name, workspace_out->name, output_primary_name(output));
-            /* Need to copy output's rect since content is not yet rendered. We
-             * can't call render_con here because render_output only proceeds
-             * if a workspace exists. */
-            content->rect = output->con->rect;
-            workspace_move_to_output(workspace, output);
+        if (output->con != workspace_out) {
+            continue;
         }
+
+        DLOG("Moving workspace \"%s\" from output \"%s\" to \"%s\" due to assignment\n",
+             workspace->name, output_primary_name(get_output_for_con(workspace)),
+             output_primary_name(output));
+
+        /* Need to copy output's rect since content is not yet rendered. We
+         * can't call render_con here because render_output only proceeds
+         * if a workspace exists. */
+        content->rect = output->con->rect;
+        workspace_move_to_output(workspace, output);
     }
 
     /* Temporarily set the focused container, might not be initialized yet. */