[Bug] "restart-interval": 0 on one-shot scripts creates silent render loop that kills all tooltips

[tteeaa]

Description:

I have discovered that setting "restart-interval": 0 on a custom module that executes a "one-shot" script (exits immediately with code 0) creates a tight restart loop that silently breaks the UI.

Because the script exits instantly, Waybar restarts it immediately. I believe this cycle stops the event loop, stopping tooltips from displaying.

Reproduction Steps:

1. Create a script repro_script.sh that outputs JSON and exits:

#!/bin/bash
echo '{"text": "HOVER ME", "tooltip": "If you see this, the bug is fixed."}'

2. Run Waybar with this minimal config:

{
    "layer": "top",
    "modules-center": ["custom/crasher", "clock"],
    "clock": {
        "tooltip": true,
        "tooltip-format": "<big>{:%Y %B}</big>\n<tt><small>{calendar}</small></tt>"

    },
    "custom/crasher": {
        "format": "{text}",
        "return-type": "json",
        "exec": "~/repro_script.sh",
        "restart-interval": 0  // <--- THE PROBLEM
    }
}

3. Hover over the Clock Module.

Expected Behavior:
The Clock tooltip should appear. If custom/crasher is restarting too fast, Waybar should warn the user or throttle the module (either way, it should have logs).

Actual Behavior:
The bar renders, but tooltips are completely dead for all modules. Logs show no errors, effectively creating a "silent failure."
Commenting out the restart-interval line will bring back the tooltips.

Environment:

• Waybar v0.15.0
• OS: Arch Linux

[DragonDuck24]

I noticed this with MPRIS when interval: 0 is set, no UI displays whatsoever, this seems to been caused by #4390
The PR created #4843 is inconsistent, it states:

As documented in man/waybar-custom.5.scd, the minimum restart interval is 1ms (0.001).
"Minimum value is 0.001 (1ms). Values smaller than 1ms will be set to 1ms."

However the implementation enforces it to 1000ms, not 1.
Additionally, Wiki pages like mpris should be updated for the changes in #4390, changing the type to double, and possibly noting that it must be >0.

[Meisterlala]

setting interval: 0 disables tooltips for the entire waybar for me, with no error in the logs.

This causes all my tooltips to disappear:

  "custom/sleep": {
    "format": "  ",
    "tooltip": "Suspend",
    "on-click": "systemctl suspend",
    "interval": 0,
  },

I have had this config for a a long time. So i assume a recent change caused this bug.

[amas0]

Okay, can disregard: I see there is an open PR for this issue.

Ran into this myself (I had an interval of 0.8 set and 0.15.0 broke my bar).

I believe the change in these lines are the culprit:

Waybar/src/ALabel.cpp

Lines 24 to 30 in a74adc5

	interval_(config_["interval"] == "once"
	? std::chrono::milliseconds::max()
	: std::chrono::milliseconds(
	(config_["interval"].isNumeric()
	? std::max(1L, // Minimum 1ms due to millisecond precision
	static_cast<long>(config_["interval"].asDouble()) * 1000)
	: 1000 * (long)interval))),

If you have any interval specified in [0, 1), then the cast to long will truncate it to 0, and you'll get the minimum 1 ms interval. This, on my machine spikes waybar CPU usage to 100% and can block other elements from working properly. On my relatively powerful desktop, the bar still functions, but on my weaker laptop all the elements stop updating properly (presumably because the 1 ms update interval is gumming up the application).

I think the right solution is to change this so the cast to long happens after the * 1000 so that intervals can be set between 0 and 1000 ms? I tested this locally and it seems to work.

Although that wouldn't address trying to set a 0 ms interval as that would get set to 1 ms. I suppose it depends on it 0 ms is a special case that should be handled.