From 75aab6e2829d63a905bfc366a136bdbace8ba05c Mon Sep 17 00:00:00 2001
From: Ian Douglas Scott <idscott@system76.com>
Date: Wed, 26 Mar 2025 12:08:46 -0700
Subject: [PATCH] shell/workspace: Clear output stack when moved user moves
 workspace

If the user explicitly moves a workspace to an output, assume that is
where the user wants it, so it shouldn't be moved back to a different
output in the future.

For persistent workspaces, the explicitly set workspace is the one that
will be stored, instead of trying to track an unbounded list of outputs
persistently.
---
 src/shell/mod.rs       | 13 +++++++------
 src/shell/workspace.rs | 11 +++++++++--
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/shell/mod.rs b/src/shell/mod.rs
index 69099c69..d64182ca 100644
--- a/src/shell/mod.rs
+++ b/src/shell/mod.rs
@@ -518,14 +518,14 @@ impl WorkspaceSet {
         }
     }
 
-    fn set_output(&mut self, new_output: &Output) {
+    fn set_output(&mut self, new_output: &Output, explicit: bool) {
         self.sticky_layer.set_output(new_output);
         for window in self.sticky_layer.windows() {
             toplevel_leave_output(&window, &self.output);
             toplevel_enter_output(&window, &new_output);
         }
         for workspace in &mut self.workspaces {
-            workspace.set_output(new_output);
+            workspace.set_output(new_output, explicit);
         }
         self.output = new_output.clone();
     }
@@ -711,7 +711,7 @@ impl Workspaces {
             .backup_set
             .take()
             .map(|mut set| {
-                set.set_output(output);
+                set.set_output(output, false);
                 set
             })
             .unwrap_or_else(|| {
@@ -738,7 +738,7 @@ impl Workspaces {
         }
         set.update_workspace_idxs(workspace_state);
         for (i, workspace) in set.workspaces.iter_mut().enumerate() {
-            workspace.set_output(output);
+            workspace.set_output(output, false);
             workspace.refresh();
             if i == set.active {
                 workspace_state.add_workspace_state(&workspace.handle, WState::Active);
@@ -790,7 +790,7 @@ impl Workspaces {
                         move_workspace_to_group(&mut workspace, &workspace_group, workspace_state);
 
                         // update mapping
-                        workspace.set_output(&new_output);
+                        workspace.set_output(&new_output, false);
                         workspace.refresh();
                         new_set.workspaces.push(workspace);
 
@@ -840,6 +840,7 @@ impl Workspaces {
         }
     }
 
+    // Move workspace from one output to another, explicitly by the user
     fn migrate_workspace(
         &mut self,
         from: &Output,
@@ -858,7 +859,7 @@ impl Workspaces {
         {
             let new_set = self.sets.get_mut(to).unwrap();
             move_workspace_to_group(&mut workspace, &new_set.group, workspace_state);
-            workspace.set_output(to);
+            workspace.set_output(to, true);
             workspace.refresh();
             new_set.workspaces.insert(new_set.active + 1, workspace);
             new_set.update_workspace_idxs(workspace_state);
diff --git a/src/shell/workspace.rs b/src/shell/workspace.rs
index bfbd672a..b6d09f99 100644
--- a/src/shell/workspace.rs
+++ b/src/shell/workspace.rs
@@ -85,7 +85,7 @@ pub struct Workspace {
     pub handle: WorkspaceHandle,
     pub focus_stack: FocusStacks,
     pub screencopy: ScreencopySessions,
-    pub output_stack: VecDeque<String>,
+    output_stack: VecDeque<String>,
     pub(super) backdrop_id: Id,
     pub dirty: AtomicBool,
 }
@@ -361,7 +361,11 @@ impl Workspace {
         &self.output
     }
 
-    pub fn set_output(&mut self, output: &Output) {
+    // Set output the workspace is on
+    //
+    // If `explicit` is `true`, the user has explicitly moved the workspace
+    // to this output, so previous outputs it was on can be forgotten.
+    pub fn set_output(&mut self, output: &Output, explicit: bool) {
         self.tiling_layer.set_output(output);
         self.floating_layer.set_output(output);
         for mapped in self.mapped() {
@@ -376,6 +380,9 @@ impl Workspace {
                 toplevel_enter_output(&surface, output);
             }
         }
+        if explicit {
+            self.output_stack.clear();
+        }
         let output_name = output.name();
         if let Some(pos) = self
             .output_stack