From 848a2d52c9eb796dac94a6f263b0518abe580c69 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Wed, 22 Apr 2026 11:45:19 -0500 Subject: fix(host-environment): detect battery correctly on Linux desktops `env-laptop-p` treated any `battery-format "%B"` value that wasn't literally "N/A" as "has a battery." On a Linux desktop using `battery-upower`, the result is "unknown". The AC adapter and USB-C power entries exist in /sys but there's no BAT*. That made desktops look like laptops. The per-machine font height switch in `font-config.el` broke as a result. The fix uses /sys/class/power_supply/BAT* as the canonical Linux signal. That's what the kernel exposes, and what upower itself reads. Other platforms keep the `battery-format` path, but the fallback now checks for a live battery status char ("!", "+", "-") instead of only excluding "N/A". Two pure helpers (`env--battery-status-char-indicates-battery-p`, `env--power-supply-has-battery-p`) keep the logic testable. The new test file covers Normal, Boundary, and Error cases for each helper. --- modules/host-environment.el | 35 ++++++++++++++++++++++++++++++----- 1 file changed, 30 insertions(+), 5 deletions(-) (limited to 'modules/host-environment.el') diff --git a/modules/host-environment.el b/modules/host-environment.el index af9248c2..832cc195 100644 --- a/modules/host-environment.el +++ b/modules/host-environment.el @@ -12,12 +12,37 @@ +(defun env--battery-status-char-indicates-battery-p (status) + "Return non-nil if STATUS indicates a real battery is present. +STATUS is the value returned by `battery-format' with the \"%B\" spec. +A real battery reports \"!\" (critical), \"+\" (charging), or \"-\" +(discharging). Desktops report \"N/A\", \"unknown\", or empty, which +all mean no battery." + (and (stringp status) + (member status '("!" "+" "-")) + t)) + +(defun env--power-supply-has-battery-p (power-supply-dir) + "Return non-nil if POWER-SUPPLY-DIR contains a BAT* entry. +Canonical Linux check. A laptop exposes directories like +/sys/class/power_supply/BAT0; a desktop exposes only AC adapters +and USB-C power entries." + (and (file-directory-p power-supply-dir) + (file-expand-wildcards (expand-file-name "BAT*" power-supply-dir)) + t)) + (defun env-laptop-p () - "Non-nil if a battery is present." - (when (and (require 'battery nil 'noerror) - battery-status-function) - (not (string= "N/A" - (battery-format "%B" (funcall battery-status-function)))))) + "Non-nil if the host has a battery. +On Linux, checks /sys/class/power_supply for BAT* entries, which is the +canonical signal. On other platforms, falls back to `battery-format' +\"%B\" and checks for a live battery status char." + (cond + ((eq system-type 'gnu/linux) + (env--power-supply-has-battery-p "/sys/class/power_supply")) + ((and (require 'battery nil 'noerror) + battery-status-function) + (env--battery-status-char-indicates-battery-p + (battery-format "%B" (funcall battery-status-function)))))) (defun env-desktop-p () "Return t if host is a laptop (has a battery), nil if not." -- cgit v1.2.3