From eb10f874e8b31f4b6542b2a7276a24dd672f080d Mon Sep 17 00:00:00 2001
From: koekeishiya <aasvi93@hotmail.com>
Date: Wed, 22 Jan 2025 22:37:09 +0100
Subject: [PATCH] #2522 fix issue that could cause a crash

---
 CHANGELOG.md          |  1 +
 src/process_manager.c |  1 +
 src/workspace.h       |  1 +
 src/workspace.m       | 18 ++++++++++++++++--
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d7f52bb6..848f60f4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Config *global setting* `split_type` is now categorized as a *space setting* instead [#2479](https://github.com/koekeishiya/yabai/issues/2479)
 - Additional options `x-axis` and `y-axis` can now be used with `config auto_balance` command [#190](https://github.com/koekeishiya/yabai/issues/190)
 - Minor adjustment to screen-padding and window-gap [#2502](https://github.com/koekeishiya/yabai/issues/2502)
+- Fix issue that could cause a crash when a newly launched application terminates rapidly during/after launch [#2522](https://github.com/koekeishiya/yabai/issues/2522)
 
 ## [7.1.5] - 2024-11-01
 ### Changed
diff --git a/src/process_manager.c b/src/process_manager.c
index 9d3fa42a..a0c0d6ed 100644
--- a/src/process_manager.c
+++ b/src/process_manager.c
@@ -103,6 +103,7 @@ static PROCESS_EVENT_HANDLER(process_handler)
 
         __atomic_store_n(&process->terminated, true, __ATOMIC_RELEASE);
         process_manager_remove_process(pm, &psn);
+        workspace_application_unobserve(g_workspace_context, process);
         __asm__ __volatile__ ("" ::: "memory");
 
         event_loop_post(&g_event_loop, APPLICATION_TERMINATED, process, 0);
diff --git a/src/workspace.h b/src/workspace.h
index eb8d81e3..9693cf8d 100644
--- a/src/workspace.h
+++ b/src/workspace.h
@@ -25,6 +25,7 @@ static inline bool workspace_is_macos_##name(void) \
 struct process;
 void *workspace_application_create_running_ns_application(struct process *process);
 void workspace_application_destroy_running_ns_application(void *context, struct process *process);
+void workspace_application_unobserve(void *context, struct process *process);
 bool workspace_application_is_observable(struct process *process);
 bool workspace_application_is_finished_launching(struct process *process);
 void workspace_application_observe_finished_launching(void *context, struct process *process);
diff --git a/src/workspace.m b/src/workspace.m
index 0f6beeca..cab2179e 100644
--- a/src/workspace.m
+++ b/src/workspace.m
@@ -86,6 +86,20 @@ void workspace_application_observe_activation_policy(void *context, struct proce
     }
 }
 
+void workspace_application_unobserve(void *ws_context, struct process *process)
+{
+    NSRunningApplication *application = __atomic_load_n(&process->ns_application, __ATOMIC_RELAXED);
+    if (application) {
+        @try {
+            [application removeObserver:ws_context forKeyPath:@"activationPolicy" context:process];
+        } @catch (NSException * __unused exception) {}
+
+        @try {
+            [application removeObserver:ws_context forKeyPath:@"finishedLaunching" context:process];
+        } @catch (NSException * __unused exception) {}
+    }
+}
+
 bool workspace_application_is_observable(struct process *process)
 {
     NSRunningApplication *application = __atomic_load_n(&process->ns_application, __ATOMIC_RELAXED);
@@ -196,7 +210,7 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
 {
     if ([keyPath isEqualToString:@"activationPolicy"]) {
         struct process *process = context;
-        assert(!process->terminated);
+        if (process->terminated) return;
 
         id result = [change objectForKey:NSKeyValueChangeNewKey];
         if ([result intValue] != process->policy) {
@@ -221,7 +235,7 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
 
     if ([keyPath isEqualToString:@"finishedLaunching"]) {
         struct process *process = context;
-        assert(!process->terminated);
+        if (process->terminated) return;
 
         id result = [change objectForKey:NSKeyValueChangeNewKey];
         if ([result intValue] == 1) {