Fix for #8077: Error "Too many recursion levels" does not stop execuition of code that uses ON DISCONNECT trigger (PR#8119)

Co-authored-by: Vlad Khorsun <hvlad@users.sourceforge.net>

src/common/StatusArg.cpp

@@ -212,6 +212,14 @@ void StatusVector::ImplStatusVector::append(const StatusVector& v) noexcept
 
 void StatusVector::ImplStatusVector::prepend(const StatusVector& v) noexcept
 {
+	auto errFrom = v.implementation->value();
+	auto lenFrom = v.implementation->firstWarning() ? v.implementation->firstWarning() : v.implementation->length();
+	auto errTo = value();
+	auto lenTo = firstWarning() ? firstWarning() : length();
+
+	if (lenFrom < lenTo && fb_utils::cmpStatus(lenFrom, errFrom, errTo))
+		return;			// already here - ToDo: check warnings
+
 	ImplStatusVector newVector(getKind(), getCode());
 
 	if (newVector.appendErrors(v.implementation))

src/common/classes/auto.h

@@ -269,6 +269,12 @@ public:
 		*value |= oldValue;
 	}
 
+	void release(T cleanBit)
+	{
+		bit &= ~cleanBit;
+		oldValue &= ~cleanBit;
+	}
+
 private:
 	// copying is prohibited
 	AutoSetRestoreFlag(const AutoSetRestoreFlag&);

src/jrd/Attachment.cpp

@@ -602,6 +602,12 @@ void Jrd::Attachment::resetSession(thread_db* tdbb, jrd_tra** traHandle)
 	}
 	catch (const Exception& ex)
 	{
+		if (att_ext_call_depth && !shutAtt)
+		{
+			flags.release(ATT_resetting);		// reset is incomplete - keep state
+			shutAtt = true;
+		}
+
 		if (shutAtt)
 			signalShutdown(isc_ses_reset_failed);
 

src/jrd/extds/ExtDS.cpp

@@ -441,9 +441,9 @@ void Provider::jrdAttachmentEnd(thread_db* tdbb, Jrd::Attachment* att, bool forc
 void Provider::releaseConnection(thread_db* tdbb, Connection& conn, bool inPool)
 {
 	ConnectionsPool* connPool = conn.getConnPool();
+	Attachment* att = conn.getBoundAtt();
 
 	{ // m_mutex scope
-		Attachment* att = conn.getBoundAtt();
 		MutexLockGuard guard(m_mutex, FB_FUNCTION);
 
 		bool found = false;
@@ -464,7 +464,42 @@ void Provider::releaseConnection(thread_db* tdbb, Connection& conn, bool inPool)
 			m_connections.add(AttToConn(NULL, &conn));
 	}
 
-	if (!inPool || !connPool || !connPool->getMaxCount() || !conn.isConnected() || !conn.resetSession(tdbb))
+	FbLocalStatus resetError;
+	inPool = inPool && connPool && connPool->getMaxCount() && conn.isConnected();
+
+	if (inPool)
+	{
+		inPool = conn.resetSession(tdbb);
+
+		// Check if reset of external session failed when parent (local) attachment
+		// is resetting or run ON DISCONNECT trigger.
+
+		const auto status = tdbb->tdbb_status_vector;
+		if (!inPool && status->hasData())
+		{
+			if (att->att_flags & ATT_resetting)
+				resetError.loadFrom(status);
+			else
+			{
+				auto req = tdbb->getRequest();
+				while (req)
+				{
+					if (req->req_trigger_action == TRIGGER_DISCONNECT)
+					{
+						resetError.loadFrom(status);
+						break;
+					}
+					req = req->req_caller;
+				}
+			}
+		}
+	}
+
+	if (inPool)
+	{
+		connPool->putConnection(tdbb, &conn);
+	}
+	else
 	{
 		{	// scope
 			MutexLockGuard guard(m_mutex, FB_FUNCTION);
@@ -477,9 +512,8 @@ void Provider::releaseConnection(thread_db* tdbb, Connection& conn, bool inPool)
 			connPool->delConnection(tdbb, &conn, false);
 
 		Connection::deleteConnection(tdbb, &conn);
+		resetError.check();
 	}
-	else
-		connPool->putConnection(tdbb, &conn);
 }
 
 void Provider::clearConnections(thread_db* tdbb)

src/jrd/extds/IscDS.cpp

@@ -274,6 +274,7 @@ bool IscConnection::resetSession(thread_db* tdbb)
 		return true;
 	}
 
+	ERR_post_nothrow(&status);
 	return false;
 }
 

src/jrd/jrd.cpp

@@ -8352,8 +8352,11 @@ static void purge_attachment(thread_db* tdbb, StableAttachmentPart* sAtt, unsign
 			const TrigVector* const trig_disconnect =
 				attachment->att_triggers[DB_TRIGGER_DISCONNECT];
 
+			// ATT_resetting may be set here only in a case when running on disconnect triggers
+			// in ALTER SESSION RESET already failed and attachment was shut down.
+			// Trying them once again here makes no sense.
 			if (!forcedPurge &&
-				!(attachment->att_flags & ATT_no_db_triggers) &&
+				!(attachment->att_flags & (ATT_no_db_triggers | ATT_resetting)) &&
 				trig_disconnect && !trig_disconnect->isEmpty())
 			{
 				ThreadStatusGuard temp_status(tdbb);