Prevent shortcut reset collisions

config/dot/quickshell/keybinds-harness.qml

@@ -13,9 +13,16 @@ ShellRoot {
             return Keybinds.rebind(current, next);
         }
 
-        function resetBind(current: string): void { Keybinds.resetBind(current); }
+        function resetBind(current: string): bool { return Keybinds.resetBind(current); }
         function resetAll(): void { Keybinds.resetAll(); }
 
+        function seedResetCollision(shipped: string, current: string, occupantShipped: string): void {
+            const overrides = {};
+            overrides[shipped] = current;
+            overrides[occupantShipped] = shipped;
+            DesktopPreferences.set("keybindOverrides", overrides);
+        }
+
         function chordFor(description: string): string {
             const found = Keybinds.binds.find(bind => bind.description === description);
             return found ? found.luaChord : "";
@@ -24,7 +31,8 @@ ShellRoot {
         function overrideState(): string {
             return JSON.stringify({
                 overrides: Keybinds.overrides,
-                count: Object.keys(Keybinds.overrides).length
+                count: Object.keys(Keybinds.overrides).length,
+                lastError: Keybinds.lastError
             });
         }
 

config/dot/quickshell/services/Keybinds.qml

@@ -108,6 +108,17 @@ Singleton {
         return "";
     }
 
+    // A moved shortcut vacates its shipped chord, so another override may use
+    // it legitimately. Refuse to reset the first shortcut until that occupant
+    // moves away; otherwise Hyprland would receive two binds on one chord.
+    function overrideOccupantFor(chord: string, exceptShipped: string): string {
+        for (const shipped in root.overrides) {
+            if (shipped !== exceptShipped && root.overrides[shipped] === chord)
+                return shipped;
+        }
+        return "";
+    }
+
     function rebind(currentChord: string, newChord: string): bool {
         if (newChord === "" || newChord === currentChord)
             return false;
@@ -133,14 +144,25 @@ Singleton {
         return true;
     }
 
-    function resetBind(currentChord: string): void {
+    function resetBind(currentChord: string): bool {
         const shipped = root.shippedChordFor(currentChord);
         if (shipped === currentChord)
-            return;
+            return true;
+
+        const occupant = root.overrideOccupantFor(shipped, shipped);
+        if (occupant !== "") {
+            root.lastError = `${shipped} is used by another rebound shortcut. Reset that shortcut first.`;
+            return false;
+        }
+
         const next = Object.assign({}, root.overrides);
         delete next[shipped];
-        DesktopPreferences.set("keybindOverrides", next);
+        if (!DesktopPreferences.set("keybindOverrides", next)) {
+            root.lastError = "That shortcut could not be reset.";
+            return false;
+        }
         root.applyReload();
+        return true;
     }
 
     function resetAll(): void {

tests/quickshell/keybind-rebind-contract.sh

@@ -17,13 +17,25 @@ set -euo pipefail
 
 repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
 harness="$repo_dir/config/dot/quickshell/keybinds-harness.qml"
-config_home="$(mktemp -d /tmp/panama-rebind-config.XXXXXX)"
+service="$repo_dir/config/dot/quickshell/services/Keybinds.qml"
 
 fail() {
     printf 'keybind rebind contract: %s\n' "$1" >&2
     exit 1
 }
 
+rg -Fq 'function overrideOccupantFor(chord: string, exceptShipped: string): string' "$service" \
+    || fail 'resetBind has no override collision guard'
+rg -Fq 'root.overrideOccupantFor(shipped, shipped)' "$service" \
+    || fail 'resetBind does not check whether another override occupies its shipped chord'
+
+if [[ "${PANAMA_KEYBINDS_STATIC_ONLY:-0}" == "1" ]]; then
+    printf 'keybind rebind contract: PASS (static)\n'
+    exit 0
+fi
+
+config_home="$(mktemp -d /tmp/panama-rebind-config.XXXXXX)"
+
 # The compositor is the live one -- that is the point -- but preferences are
 # isolated so this cannot leave an override in the user's real settings.
 # hyprctl reload re-reads the real settings file, so the compositor is only
@@ -87,6 +99,19 @@ sleep 0.5
 [[ "$(qs_for_harness ipc call keybinds-test overrideState | jq -r .count)" == "0" ]] \
     || fail 'resetAll left overrides behind'
 
+# Terminal moved away from its shipped chord, then Files moved into it.
+# Resetting Terminal must refuse instead of producing two binds on one chord.
+qs_for_harness ipc call keybinds-test seedResetCollision \
+    "$terminal" "SUPER + SHIFT + F9" "$files" >/dev/null
+sleep 0.2
+[[ "$(qs_for_harness ipc call keybinds-test resetBind "SUPER + SHIFT + F9")" == "false" ]] \
+    || fail 'resetBind reclaimed a shipped chord occupied by another override'
+collision_state="$(qs_for_harness ipc call keybinds-test overrideState)"
+jq -e --arg terminal "$terminal" --arg files "$files" \
+    '.count == 2 and .overrides[$terminal] == "SUPER + SHIFT + F9" and .overrides[$files] == $terminal and (.lastError | length > 0)' \
+    <<<"$collision_state" >/dev/null \
+    || fail "a refused reset changed overrides or gave no explanation: $collision_state"
+
 trap - EXIT
 cleanup
 printf 'keybind rebind contract: PASS\n'