From c337fd5467f52b5f79f653b7e71f945cc8cf09d1 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Tue, 6 Sep 2011 18:16:39 -0700
Subject: [PATCH] Child tasks take a ref to their parents

This is so that when a child dies after the parent, it still holds a valid
pointer and can call supervisor->kill() safely.
---
 src/rt/rust_task.cpp           | 10 ++++++++++
 src/test/run-fail/spawnfail.rs | 14 ++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 src/test/run-fail/spawnfail.rs

diff --git a/src/rt/rust_task.cpp b/src/rt/rust_task.cpp
index ab29b106783..31a3324f1d4 100644
--- a/src/rt/rust_task.cpp
+++ b/src/rt/rust_task.cpp
@@ -86,6 +86,9 @@ rust_task::rust_task(rust_scheduler *sched, rust_task_list *state,
 
     stk = new_stk(sched, this, 0);
     user.rust_sp = stk->limit;
+    if (supervisor) {
+        supervisor->ref();
+    }
 }
 
 rust_task::~rust_task()
@@ -107,6 +110,10 @@ rust_task::~rust_task()
         }
     }
 
+    if (supervisor) {
+        supervisor->deref();
+    }
+
     kernel->release_task_id(user.id);
 
     /* FIXME: tighten this up, there are some more
@@ -294,6 +301,9 @@ rust_task::unsupervise()
              "task %s @0x%" PRIxPTR
              " disconnecting from supervisor %s @0x%" PRIxPTR,
              name, this, supervisor->name, supervisor);
+    if (supervisor) {
+        supervisor->deref();
+    }
     supervisor = NULL;
     propagate_failure = false;
 }
diff --git a/src/test/run-fail/spawnfail.rs b/src/test/run-fail/spawnfail.rs
new file mode 100644
index 00000000000..0ff641fbe95
--- /dev/null
+++ b/src/test/run-fail/spawnfail.rs
@@ -0,0 +1,14 @@
+// Currently failure doesn't propagate correctly to owning tasks so xfailed
+// xfail-test
+// error-pattern:explicit
+use std;
+import std::task;
+
+// We don't want to see any invalid reads
+fn main() {
+    fn f() {
+        fail;
+    }
+    let g = f;
+    task::spawn(g);
+}
\ No newline at end of file