merge revision(s) 5680c38c75aeb5cbd219aafa8eb48c315f287d97,f5d20411386ff2552ff27661387ddc4bae1ebc30: [Backport #17573]

	Use valid `ec` for postponed job.

	Postponed job can be registered from non-Ruby thread, which means
	`ec` in TLS can be NULL. In this case, use main thread's `ec` instead.

	See https://github.com/ruby/ruby/pull/4108
	and https://github.com/ruby/ruby/pull/4336
	---
	 vm_trace.c | 16 ++++++++++++----
	 1 file changed, 12 insertions(+), 4 deletions(-)

	Avoid assert failure when NULL EC is expected

	After 5680c38c75aeb5cbd219aafa8eb48c315f287d97, postponed job APIs now
	expect to be called on native threads not managed by Ruby and handles
	getting a NULL execution context. However, in debug builds the change
	runs into an assertion failure with GET_EC() which asserts that EC is
	non-NULL. Avoid the assertion failure by passing `false` for `expect_ec`
	instead as the intention is to handle when there is no EC.

	Add a test from John Crepezzi and John Hawthorn to exercise this
	situation.

	See GH-4108
	See GH-5094

	[Bug #17573]

	Co-authored-by: John Hawthorn <john@hawthorn.email>
	Co-authored-by: John Crepezzi <john.crepezzi@gmail.com>
	---
	 ext/-test-/postponed_job/postponed_job.c       | 31 ++++++++++++++++++++++++++
	 test/-ext-/postponed_job/test_postponed_job.rb |  7 ++++++
	 vm_trace.c                                     |  2 +-
	 3 files changed, 39 insertions(+), 1 deletion(-)

1 files changed, 12 insertions, 4 deletions

diff --git a/vm_trace.c b/vm_trace.c
index b16ec77e5a..bb4fdefd7c 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -1592,6 +1592,14 @@ postponed_job_register(rb_execution_context_t *ec, rb_vm_t *vm,
     return PJRR_SUCCESS;
 }
 
+static rb_execution_context_t *
+get_valid_ec(rb_vm_t *vm)
+{
+    rb_execution_context_t *ec = rb_current_execution_context();
+    if (ec == NULL) ec = rb_vm_main_ractor_ec(vm);
+    return ec;
+}
+
 /*
  * return 0 if job buffer is full
  * Async-signal-safe
@@ -1599,8 +1607,8 @@ postponed_job_register(rb_execution_context_t *ec, rb_vm_t *vm,
 int
 rb_postponed_job_register(unsigned int flags, rb_postponed_job_func_t func, void *data)
 {
-    rb_execution_context_t *ec = GET_EC();
-    rb_vm_t *vm = rb_ec_vm_ptr(ec);
+    rb_vm_t *vm = GET_VM();
+    rb_execution_context_t *ec = get_valid_ec(vm);
 
   begin:
     switch (postponed_job_register(ec, vm, flags, func, data, MAX_POSTPONED_JOB, vm->postponed_job_index)) {
@@ -1618,8 +1626,8 @@ rb_postponed_job_register(unsigned int flags, rb_postponed_job_func_t func, void
 int
 rb_postponed_job_register_one(unsigned int flags, rb_postponed_job_func_t func, void *data)
 {
-    rb_execution_context_t *ec = GET_EC();
-    rb_vm_t *vm = rb_ec_vm_ptr(ec);
+    rb_vm_t *vm = GET_VM();
+    rb_execution_context_t *ec = get_valid_ec(vm);
     rb_postponed_job_t *pjob;
     rb_atomic_t i, index;