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P0 discovery: stop dead optional probes after association fault without losing evidence #184

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Merged
masarray merged 2 commits into from
Oct 15, 2026
Merged

P0 discovery: stop dead optional probes after association fault without losing evidence #184

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910adaa
discovery: stop optional probes after association loss and retain pri…
masarray Oct 15, 2026
2539da2
discovery: retain all observed VMD domains when optional enrichment f…
masarray Oct 15, 2026
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34 changes: 23 additions & 11 deletions src/mms/live_discovery.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -375,24 +375,33 @@ MmsLiveDiscoveryResult MmsLiveDiscoveryClient::discover(
"Domain discovery exceeded the configured domain bound.");
}

// VMD Domain names are already observed wire evidence, even if a later
// per-domain GetNameList faults. Keep every proven domain in the canonical
// identity inventory without inventing LN variables or DataSet contents.
for (const auto& domain : domains) {
result.names.domain_variables.try_emplace(domain);
}
for (const auto& domain : domains) {
// A failed confirmed exchange closes the association. Keep earlier
// successful domain evidence; never manufacture additional failed
// optional probe entries for an already-disconnected peer.
if (!association_.associated()) break;
try {
result.names.domain_variables.emplace(
result.names.domain_variables.at(domain) = get_name_list(
MmsGetNameListObjectClass::named_variable,
domain,
get_name_list(
MmsGetNameListObjectClass::named_variable,
domain,
options,
result.wire_budget,
stop_token));
options,
result.wire_budget,
stop_token);
} catch (const std::exception& exception) {
if (!options.continue_on_optional_probe_error) {
throw;
}
result.names.domain_variables.emplace(domain, std::vector<std::string>{});
// Seeded VMD domain remains with no claimed variable evidence.
result.diagnostics.push_back(optional_probe_error(
"NamedVariable", domain, exception));
}
if (!association_.associated()) break;
Comment thread
masarray marked this conversation as resolved.

try {
result.names.domain_variable_lists.emplace(
Expand All @@ -417,12 +426,13 @@ MmsLiveDiscoveryResult MmsLiveDiscoveryClient::discover(
result.report_inventory = MmsReportInventoryBuilder::build(result.names);

const auto readDataSetDirectories = [&] {
if (!options.read_data_set_directories) return;
if (!options.read_data_set_directories || !association_.associated()) return;
const std::size_t count = std::min(
options.maximum_data_set_directories,
result.report_inventory.data_sets.size());
result.data_set_directories.reserve(count);
for (std::size_t index = 0U; index < count; ++index) {
if (!association_.associated()) break;
MmsDataSetDirectoryEvidence evidence;
evidence.candidate = result.report_inventory.data_sets[index];
try {
Expand Down Expand Up @@ -452,7 +462,7 @@ MmsLiveDiscoveryResult MmsLiveDiscoveryClient::discover(
};

const auto probeVariableTypes = [&] {
if (!options.probe_variable_types) return;
if (!options.probe_variable_types || !association_.associated()) return;
auto candidates = build_logical_node_type_probe_candidates(
result.names, options.maximum_variable_type_probes);
if (options.use_verified_data_set_type_hints) {
Expand All @@ -472,6 +482,7 @@ MmsLiveDiscoveryResult MmsLiveDiscoveryClient::discover(
result.variable_types.reserve(candidates.size());

for (const auto& candidate : candidates) {
if (!association_.associated()) break;
MmsVariableTypeEvidence evidence;
evidence.variable = candidate;
try {
Expand Down Expand Up @@ -514,12 +525,13 @@ MmsLiveDiscoveryResult MmsLiveDiscoveryClient::discover(
readDataSetDirectories();
}

if (options.probe_report_controls) {
if (options.probe_report_controls && association_.associated()) {
const std::size_t count = std::min(
options.maximum_report_control_probes,
result.report_inventory.report_controls.size());
result.report_controls.reserve(count);
for (std::size_t index = 0U; index < count; ++index) {
if (!association_.associated()) break;
MmsReportControlEvidence evidence;
evidence.candidate = result.report_inventory.report_controls[index];
evidence.requested_attributes = select_report_attributes(
Expand Down
51 changes: 47 additions & 4 deletions tests/test_live_discovery.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -678,10 +678,52 @@ void disconnected_optional_probes_do_not_inflate_wire_budget() {
CHECK(transport.sent().size() == 6U); // 2 handshake + 4 actual requests
CHECK(result.variable_types.size() == 1U);
CHECK(!result.variable_types.front().success());
CHECK(result.data_set_directories.size() == 1U);
CHECK(!result.data_set_directories.front().success());
CHECK(result.report_controls.size() == 1U);
CHECK(!result.report_controls.front().success());
// Inventory still exposes the configured DataSet/RCB identity, while
// unattempted enrichment remains absent, never synthetic failures.
CHECK(result.report_inventory.data_sets.size() == 1U);
CHECK(result.report_inventory.report_controls.size() == 1U);
CHECK(result.data_set_directories.empty());
CHECK(result.report_controls.empty());
}

void association_loss_preserves_completed_domain_evidence_without_dead_probes() {
ScriptedTransport transport;
queue_handshake(transport);
transport.push_receive(wrap_application(
mms::MmsServiceCodec::encode_get_name_list_response_p_data(
{1U, {"OLS501LD0", "OLS501LD1"}, false})));
transport.push_receive(wrap_application(
mms::MmsServiceCodec::encode_get_name_list_response_p_data(
{2U, {"LLN0$ST$Mod$stVal"}, false})));
// Third GetNameList (DataSet names for LD0) is sent but times out.
// Do not enumerate LD1 after the association is no longer usable.
mms::MmsAssociationRuntime association{transport};
association.connect({"127.0.0.1", 102U});

mms::MmsLiveDiscoveryOptions options;
options.probe_variable_types = false;
options.read_data_set_directories = false;
options.probe_report_controls = false;
const auto result = mms::MmsLiveDiscoveryClient{association}.discover(options);

CHECK(!association.associated());
CHECK(result.partial());
CHECK(result.names.domain_variables.size() == 2U);
CHECK(result.names.domain_variables.at("OLS501LD0").size() == 1U);
CHECK(result.names.domain_variable_lists.size() == 1U);
CHECK(result.names.domain_variable_lists.at("OLS501LD0").empty());
CHECK(result.names.domain_variables.at("OLS501LD1").empty());
// The second domain is observed from VMD but its variables are unknown.
// Canonical identity reconciliation must not mistake partial enumeration
// for a genuine single-domain IED.
const auto model = mms::MmsLiveModelBuilder::build(result);
CHECK(model.identity.logical_device_aliases.count("OLS501LD0") == 1U);
CHECK(model.identity.logical_device_aliases.count("OLS501LD1") == 1U);
CHECK(result.wire_budget.get_name_list == 3U);
CHECK(result.wire_budget.get_variable_access_attributes == 0U);
CHECK(result.wire_budget.get_named_variable_list_attributes == 0U);
CHECK(result.wire_budget.read_report_controls == 0U);
CHECK(transport.sent().size() == 5U); // 2 handshake + exactly 3 sends
}

void pagination_without_forward_progress_is_rejected() {
Expand Down Expand Up @@ -716,6 +758,7 @@ int main() {
case_distinct_ln_type_probes_are_preserved();
verified_data_set_hints_restore_late_ln_type_schema();
disconnected_optional_probes_do_not_inflate_wire_budget();
association_loss_preserves_completed_domain_evidence_without_dead_probes();
pagination_without_forward_progress_is_rejected();
std::cout << "Live MMS discovery and model parity tests passed.\n";
return 0;
Expand Down
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