Summarize and merge MultiOperationResultSetWithException from settled Groups.

Co-authored-by: Cursor <cursoragent@cursor.com>

CMakeLists.txt

@@ -87,6 +87,7 @@ add_library(spinscale SHARED
 	src/puppetApplication.cpp
 	src/runtime.cpp
 	src/callableTracer.cpp
+	src/multiOperationResultSet.cpp
 )
 
 set_target_properties(spinscale PROPERTIES

README.md

@@ -202,17 +202,19 @@ nursery.launch(
 		nvc.checkAndRethrowException();
 	});
 
-nursery.requestCancelOnAll();
 nursery.closeAdmission();
+nursery.requestCancelOnAll();
 nursery.syncAwaitAllSettlements(
 	sscl::ComponentThread::getSelf()->getIoContext());
 ```
 
 Each slot owns a `SyncCancelerForAsyncWork`. `requestCancelOnAll()` only signals
 cooperative stop; it does not destroy invokers. Invokers are retired when their
-completion callbacks run. Call `closeAdmission()` explicitly before
-`asyncAwaitAllSettlements()` or `syncAwaitAllSettlements()`; those APIs wait until
-all slots have retired naturally and throw if admission is still open.
+completion callbacks run. Call `closeAdmission()` before `requestCancelOnAll()`
+so no new work can be admitted after cancel begins, and call `closeAdmission()`
+explicitly before `asyncAwaitAllSettlements()` or `syncAwaitAllSettlements()`;
+those APIs wait until all slots have retired naturally and throw if admission is
+still open.
 
 `syncAwaitAllSettlements()` runs a nested `io_context` loop on the **calling
 thread** (it blocks in `run_one()` until every slot has retired). Pass the

include/spinscale/co/nonViralTaskNursery.h

@@ -55,9 +55,6 @@ struct MemberInvoker : MemberInvokerBase
  *	nursery member. The external submitter should add the complete flow to the
  *	nursery and then return; the nursery owns that flow until the flow settles.
  *
- *	Call closeAdmission() explicitly before asyncAwaitAllSettlements() or
- *	syncAwaitAllSettlements().
- *
  *	syncAwaitAllSettlements() runs a nested io_context loop on the calling
  *	thread (AsynchronousBridge). Pass the calling thread's io_context —
  *	typically
@@ -240,6 +237,36 @@ public:
 		s.rsrc.admissionOpen = true;
 	}
 
+	/**	EXPLANATION:
+	 * Stopping a nursery: always closeAdmission() before
+	 * requestCancelOnAll(). requestCancelOnAll() only marks currently
+	 * ACTIVE_UNSETTLED slots; it does not refuse new leases. If cancel
+	 * runs while admission is still open, a concurrent submitter can still
+	 * getNewSlotLease() / launch() after cancel has fanned out, and that
+	 * newly admitted work will not have been cancelled — it races past the
+	 * stop wave and keeps the drain from reaching "all settled" until it
+	 * finishes on its own (or a later cancel). Closing admission first
+	 * seals the nursery so cancel applies to a fixed membership set, then
+	 * drain with asyncAwaitAllSettlements() / syncAwaitAllSettlements()
+	 * (those APIs also require admission already closed).
+	 *
+	 * Preferred stop stack for a daemon/service that enqueues request
+	 * coroutines into the nursery: keep protocol "stop listening /
+	 * disconnect / refuse new connections and requests" separate from
+	 * protocol state destruction. Stop accepting at the protocol level
+	 * first, then nursery closeAdmission(), then requestCancelOnAll(),
+	 * then cancel any awaited I/O owned outside the cancelers, then drain,
+	 * then destroy protocol state. That ordering stops new work at the
+	 * source before admission is sealed.
+	 *
+	 * If the daemon/service cannot disconnect/stop listening separately
+	 * from destruction, the spinscale-using embedding project must handle
+	 * closed-admission failures when it tries to enqueue. For example,
+	 * catch the "admission closed" throw around nursery.launch() (or in
+	 * the factory that calls it) and emit a protocol-specific failure such
+	 * as "connection failed" or "request timed out" instead of letting the
+	 * exception escape the accept/request path unbounded.
+	 */
 	void closeAdmission()
 	{
 		sscl::SpinLock::Guard guard(s.lock);

include/spinscale/multiOperationResultSet.h

@@ -4,6 +4,9 @@
 #include <exception>
 
 namespace sscl {
+namespace co {
+struct Group;
+} // namespace co
 
 /** Plain aggregate for fan-out / fan-in results returned from coroutines. */
 struct MultiOperationResultSet
@@ -38,9 +41,29 @@ struct MultiOperationResultSetWithException
 	  memberFailureException(memberFailureExceptionIn)
 	{}
 
+	/** Summarize a settled Group into counts + aggregated member failure. */
+	explicit MultiOperationResultSetWithException(const co::Group &group);
+
 	bool hasMemberFailure() const
 		{ return memberFailureException != nullptr; }
 
+	/** Combine this result set with another phase's counts and exception. */
+	MultiOperationResultSetWithException mergeWith(
+		const MultiOperationResultSetWithException &other) const
+	{
+		std::exception_ptr memberFailure = memberFailureException;
+		if (!memberFailure && other.hasMemberFailure()) {
+			memberFailure = other.memberFailureException;
+		}
+
+		return MultiOperationResultSetWithException(
+			MultiOperationResultSet(
+				results.nTotal + other.results.nTotal,
+				results.nSucceeded + other.results.nSucceeded,
+				results.nFailed + other.results.nFailed),
+			memberFailure);
+	}
+
 	MultiOperationResultSet results;
 	std::exception_ptr memberFailureException = nullptr;
 };

src/multiOperationResultSet.cpp

@@ -0,0 +1,35 @@
+#include <boostAsioLinkageFix.h>
+
+#include <spinscale/multiOperationResultSet.h>
+#include <spinscale/co/group.h>
+
+namespace sscl {
+
+MultiOperationResultSetWithException::MultiOperationResultSetWithException(
+	const co::Group &group)
+{
+	unsigned int nSucceeded = 0;
+	unsigned int nFailed = 0;
+	using SettlementType = co::Group::SettlementDescriptor::TypeE;
+
+	for (const auto &desc : group.s.rsrc.settlements)
+	{
+		if (desc.type == SettlementType::EXCEPTION_THROWN) {
+			nFailed++;
+		}
+		else {
+			nSucceeded++;
+		}
+	}
+
+	results = MultiOperationResultSet(
+		static_cast<unsigned int>(group.s.rsrc.settlements.size()),
+		nSucceeded,
+		nFailed);
+
+	if (nFailed > 0) {
+		memberFailureException = group.captureAggregatedGroupExceptions();
+	}
+}
+
+} // namespace sscl