### Problem
Waybar segfaults on startup when `niri/workspaces` is the only configured
module (default options). Right after the first `WorkspacesChanged` event:
Thread 1 "waybar" received signal SIGSEGV
#0 gtk_label_set_markup ()
#1 waybar::modules::niri::Workspaces::doUpdate () at src/modules/niri/workspaces.cpp:106
### Root cause
[doUpdate()](cci:1://file:///home/lj/Downloads/Waybar/src/modules/niri/window.cpp:27:0-90:1) set the label markup via:
static_cast<Gtk::Label*>(button.get_children()[0])->set_markup(name);
The button's child *is* a valid `GtkLabel`, but gtkmm's `get_children()`
returns it wrapped as a generic `Gtk::Widget` (confirmed: `dynamic_cast`
to `Gtk::Label*` yields `nullptr`). The unchecked `static_cast` then
performs an invalid downcast, producing a corrupt pointer whose `gobj()`
is garbage (`0x1`), so `gtk_label_set_markup()` dereferences it and crashes.
This is reliably triggered when no other module has instantiated a
`Gtk::Label` yet (so the `Gtk::Label` wrapper isn't registered), which is
exactly the case for a `niri/workspaces`-only bar. The same idiom exists in
`sway/workspaces` and `wayfire/workspaces`; it's masked there because typical
configs include other label-using modules.
### Testing
- Reproduced the crash on 0.15.0 / current `master` with a minimal
`"modules-left": ["niri/workspaces"]` config under niri.
- After the fix: no crash; three workspace buttons render with correct
names/labels (`niri-workspace-1/2/3`).
This commit addresses memory churn caused by implicit deep copies during traversal and allocation of complex structures:
- Replaced pass-by-value 'Json::Value' in std::ranges and range-based for loops with 'const auto&' or 'const Json::Value&' in Hyprland modules, preventing large JSON tree duplications on every update.
- Fixed implicit string and pair copies in UPower and CPU Frequency loops by converting 'auto' to 'const auto&' where possible.
- Added 'std::vector::reserve' calls before 'push_back' loops in MPRIS, Niri, and CFFI modules to prevent exponential vector reallocation during initialization.
Signed-off-by: Austin Horstman <khaneliman12@gmail.com>
niri v25.08 added window positions to IPC, so waybar actually has the
information stored in json around.
This handles the associated WindowLayoutsChanged IPC message to keep the
position up to date in memory, and adds a couple of format messages to
show the current column, so one can dislpay where we are in the
workspace (in the hope of improving this feeling of being lost...)
Ideally a visual representation of the workspace like the one
illustrated in the PR[1] would be even better but this will probably do
for now.
Link: https://github.com/YaLTeR/niri/pull/1265#issuecomment-2724621758 [1]
Alex