fix(recording): scope wf-recorder stop signal to our own process

Stopping a Wayland recording ran pkill -INT wf-recorder, which signals every wf-recorder on the system — including an unrelated screen capture the user started outside Emacs. The stop path now scopes the producer-first interrupt to the wf-recorder child of our own recording shell via pkill -P <shell-pid>, in the new cj/recording--interrupt-child-wf-recorder helper.

The producer-first ordering is unchanged: wf-recorder still gets SIGINT before the process-group signal so ffmpeg sees a clean EOF on pipe:0 and finalizes the MKV. The orphan-cleanup at recording start stays a broad by-name kill on purpose — those leftover recorders come from crashed sessions whose shells are already dead, so there is no live PID to scope to. Tests cover the scoped call, the nil-PID no-op, and that the bare system-wide form is never used.

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/test-video-audio-recording--interrupt-child-wf-recorder.el b/tests/test-video-audio-recording--interrupt-child-wf-recorder.el
new file mode 100644
index 00000000..6e4cda1c
--- /dev/null
+++ b/tests/test-video-audio-recording--interrupt-child-wf-recorder.el
@@ -0,0 +1,56 @@
+;;; test-video-audio-recording--interrupt-child-wf-recorder.el --- Tests for scoped wf-recorder interrupt -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for cj/recording--interrupt-child-wf-recorder.
+;; Verifies the producer-first stop signal targets only the wf-recorder
+;; child of this module's own shell process, not every wf-recorder on the
+;; system.
+
+;;; Code:
+
+(require 'ert)
+
+;; Stub dependencies before loading the module
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+(require 'video-audio-recording)
+
+;;; Normal Cases
+
+(ert-deftest test-video-audio-recording--interrupt-child-wf-recorder-normal-scopes-to-parent-pid ()
+  "Normal: interrupt is scoped to the wf-recorder child of the given PID."
+  (let ((captured nil))
+    (cl-letf (((symbol-function 'call-process)
+               (lambda (&rest args) (setq captured args) 0)))
+      (cj/recording--interrupt-child-wf-recorder 12345)
+      ;; Targets wf-recorder, by parent PID, with SIGINT — not a bare
+      ;; system-wide name match.
+      (should (member "-INT" captured))
+      (should (member "-P" captured))
+      (should (member "12345" captured))
+      (should (member "wf-recorder" captured)))))
+
+;;; Boundary Cases
+
+(ert-deftest test-video-audio-recording--interrupt-child-wf-recorder-boundary-nil-pid-no-call ()
+  "Boundary: a nil PID issues no kill at all (nothing to scope to)."
+  (let ((called nil))
+    (cl-letf (((symbol-function 'call-process)
+               (lambda (&rest _) (setq called t) 0)))
+      (cj/recording--interrupt-child-wf-recorder nil)
+      (should-not called))))
+
+;;; Error Cases
+
+(ert-deftest test-video-audio-recording--interrupt-child-wf-recorder-error-never-bare-name ()
+  "Error: must never call pkill with only the program name (system-wide kill)."
+  (let ((captured nil))
+    (cl-letf (((symbol-function 'call-process)
+               (lambda (&rest args) (setq captured args) 0)))
+      (cj/recording--interrupt-child-wf-recorder 999)
+      ;; The whole point of the fix: a parent-scoping flag is always present.
+      (should (member "-P" captured)))))
+
+(provide 'test-video-audio-recording--interrupt-child-wf-recorder)
+;;; test-video-audio-recording--interrupt-child-wf-recorder.el ends here