SERVER-115160 Remove stub fallback parsers from listMqlEntities (#45142)

GitOrigin-RevId: b0466ba903392d3e85f8e6aad2c5a5c700e94dfd

jstests/aggregation/expressions/null_chars_string_input.js

@@ -474,21 +474,7 @@ const allPipelines = [
 ];
 const testedStages = new Set(allPipelines.flatMap((pipeline) => pipeline.map((obj) => Object.keys(obj)[0])));
 
+// Confirm that every aggregation stage is either tested or explicitly skipped.
 for (const aggStage of aggStages) {
-    // Confirm that every aggregation stage is either tested or explicitly skipped.
-    if (testedStages.has(aggStage) || skips.has(aggStage)) {
-        continue;
-    }
-    // If we reach here, then the aggregation stage has not been tested or skipped. We confirm that
-    // this stage is a stub stage that is defined for tests in aggregation_stage_stub_parsers.json.
-    // If not, we will trigger the assertion and should test or skip the new stage.
-    try {
-        coll.aggregate([{[aggStage]: {}}]);
-        assert(false, aggStage + " has not been tested for null bytes.");
-    } catch (e) {
-        if (e.code !== 10918500) {
-            // Stub aggregation stage error code.
-            assert(false, aggStage + " has not been tested for null bytes.");
-        }
-    }
+    assert(testedStages.has(aggStage) || skips.has(aggStage), aggStage + " has not been tested for null bytes.");
 }

jstests/auth/lib/commands_lib.js

@@ -243,10 +243,6 @@ const skippedAuthTestingAggStages = [
     "$sessionWindow",
     "$validate",
     "$setStreamMeta",
-
-    // The following stages are stubs defined in aggregation_stage_stub_parsers.json.
-    "$stubStage",
-    "$testFoo",
 ];
 
 // The following commands are skipped in 'authCommandsLib' because they are unable to be

jstests/core/timeseries/query/agg_stage_coverage.js

@@ -52,10 +52,9 @@ for (let i = 0; i < 10; i++) {
  *    This is expected for all stages that return **user** inserted documents.
  * 4. skippedStages: These stages **must** either be
  *    (a) run on the admin db
- *    (b) stub stages for testing
- *    (c) tested elsewhere
- *    (d) stages that can only run in stream processors
- *    (e) internal only stages (cannot be made by user requests) that run on oplog data
+ *    (b) tested elsewhere
+ *    (c) stages that can only run in stream processors
+ *    (d) internal only stages (cannot be made by user requests) that run on oplog data
  *
  * Once you've determined which set your new aggregation stage belongs to add a test case to the appropriate set.
  * Each set has a slightly different test format.
@@ -291,10 +290,9 @@ const unpackTests = [
 // The following pipeline stages do not need to be tested for timeseries collections.
 // Stages that are skipped **must** be one of the following:
 // 1. Stages that only run on the admin database.
-// 2. Stub stages that are defined for tests in aggregation_stage_stub_parsers.json.
-// 3. Stages that are tested elsewhere.
-// 4. Stages that can only run in stream processors.
-// 5. Stages that cannot be made by user requests and run on oplog data.
+// 2. Stages that are tested elsewhere.
+// 3. Stages that can only run in stream processors.
+// 4. Stages that cannot be made by user requests and run on oplog data.
 const skippedStages = [
     // All change stream stages are temporarily here. TODO SERVER-113494 enable tests here.
     "$changeStream",
@@ -331,10 +329,6 @@ const skippedStages = [
     "$_internalAllCollectionStats",
     "$queue",
 
-    // Stub stages defined in 'aggregation_stage_stub_parsers.json'.
-    "$stubStage",
-    "$testFoo",
-
     // Stages tested in 'search_disallowed_on_timeseries.js', since they require extra setup.
     "$search",
     "$searchMeta",

src/mongo/db/exec/agg/list_mql_entities_stage.cpp

@@ -79,9 +79,12 @@ ListMqlEntitiesStage::ListMqlEntitiesStage(
     MqlEntityTypeEnum type,
     const LiteParsedDocumentSource::ParserMap& docSourceParserMap)
     : Stage(stageName, pExpCtx), _type(type) {
-    for (auto&& [stageName, _] : docSourceParserMap) {
+    for (auto&& [stageName, registration] : docSourceParserMap) {
+        // Exclude this stage if it is a stub that has no primary parser.
+        if (registration.isExecutable()) {
             _results.push_back(stageName);
         }
+    }
 
     // Canonicalize output order of results. Sort in descending order so that we can use a cheap
     // 'pop_back()' to return the results in order.

src/mongo/db/extension/host/load_stub_parsers.cpp

@@ -92,7 +92,8 @@ void registerStubParser(std::string stageName, std::string message, FeatureFlag*
                                                      std::move(stubParser),
                                                      featureFlag,
                                                      AllowedWithApiStrict::kAlways,
-                                                     AllowedWithClientType::kAny);
+                                                     AllowedWithClientType::kAny,
+                                                     true /*isStub*/);
 }
 
 void registerUnloadedExtensionStubParsers() {

src/mongo/db/pipeline/lite_parsed_document_source.cpp

@@ -82,10 +82,11 @@ void LiteParsedDocumentSource::LiteParserRegistration::setPrimaryParser(LitePars
 }
 
 void LiteParsedDocumentSource::LiteParserRegistration::setFallbackParser(
-    LiteParserInfo&& lpi, IncrementalRolloutFeatureFlag* ff) {
+    LiteParserInfo&& lpi, IncrementalRolloutFeatureFlag* ff, bool isStub) {
     _fallbackParser = std::move(lpi);
     _primaryParserFeatureFlag = ff;
     _fallbackIsSet = true;
+    _isStub = isStub;
 }
 
 bool LiteParsedDocumentSource::LiteParserRegistration::isPrimarySet() const {
@@ -117,7 +118,8 @@ void LiteParsedDocumentSource::registerFallbackParser(const std::string& name,
                                                       Parser parser,
                                                       FeatureFlag* parserFeatureFlag,
                                                       AllowedWithApiStrict allowedWithApiStrict,
-                                                      AllowedWithClientType allowedWithClientType) {
+                                                      AllowedWithClientType allowedWithClientType,
+                                                      bool isStub) {
     if (parserMap.contains(name)) {
         const auto& registration = parserMap.at(name);
 
@@ -151,8 +153,8 @@ void LiteParsedDocumentSource::registerFallbackParser(const std::string& name,
                 ifrFeatureFlag != nullptr);
     }
 
-    registration.setFallbackParser({parser, allowedWithApiStrict, allowedWithClientType},
-                                   ifrFeatureFlag);
+    registration.setFallbackParser(
+        {parser, allowedWithApiStrict, allowedWithClientType}, ifrFeatureFlag, isStub);
 }
 
 void LiteParsedDocumentSource::unregisterParser_forTest(const std::string& name) {

src/mongo/db/pipeline/lite_parsed_document_source.h

@@ -112,12 +112,20 @@ public:
         void setPrimaryParser(LiteParserInfo&& lpi);
 
         // TODO SERVER-114028 Update when fallback parsing supports all feature flags.
-        void setFallbackParser(LiteParserInfo&& lpi, IncrementalRolloutFeatureFlag* ff);
+        void setFallbackParser(LiteParserInfo&& lpi,
+                               IncrementalRolloutFeatureFlag* ff,
+                               bool isStub = false);
 
         bool isPrimarySet() const;
 
         bool isFallbackSet() const;
 
+        // Returns true if the parser is executable, meaning it has either a primary or a non-stub
+        // fallback.
+        bool isExecutable() const {
+            return _primaryIsSet || !_isStub;
+        }
+
     private:
         // The preferred method of parsing this LiteParsedDocumentSource. If the feature flag is
         // enabled, the primary parser will be used to parse the stage.
@@ -137,6 +145,9 @@ public:
 
         // Whether or not the fallback parser has been registered or not.
         bool _fallbackIsSet = false;
+
+        // Whether the fallback parser is a stub parser that just throws an error.
+        bool _isStub = false;
     };
 
     using ParserMap = StringMap<LiteParsedDocumentSource::LiteParserRegistration>;
@@ -170,7 +181,8 @@ public:
                                        Parser parser,
                                        FeatureFlag* parserFeatureFlag,
                                        AllowedWithApiStrict allowedWithApiStrict,
-                                       AllowedWithClientType allowedWithClientType);
+                                       AllowedWithClientType allowedWithClientType,
+                                       bool isStub = false);
 
     /**
      * Function that will be used as an alternate parser for a document source that has been