Revert "SERVER-45530 Implement $match and $project duplication and pushdown across $unionWith"

This reverts commit 942ec3300e82672536f34d8273314c5504ae91fb.

8 files changed, 16 insertions, 244 deletions

diff --git a/src/mongo/db/pipeline/document_source_change_stream.cpp b/src/mongo/db/pipeline/document_source_change_stream.cpp
index 9af00b5773c..153bc685a70 100644
--- a/src/mongo/db/pipeline/document_source_change_stream.cpp
+++ b/src/mongo/db/pipeline/document_source_change_stream.cpp
@@ -139,6 +139,10 @@ Value DocumentSourceOplogMatch::serialize(optional<ExplainOptions::Verbosity> ex
     return Value();
 }
 
+DocumentSourceOplogMatch::DocumentSourceOplogMatch(BSONObj filter,
+                                                   const intrusive_ptr<ExpressionContext>& expCtx)
+    : DocumentSourceMatch(std::move(filter), expCtx) {}
+
 void DocumentSourceChangeStream::checkValueType(const Value v,
                                                 const StringData filedName,
                                                 BSONType expectedType) {
diff --git a/src/mongo/db/pipeline/document_source_change_stream.h b/src/mongo/db/pipeline/document_source_change_stream.h
index 9eeaaf19b9b..9570f2e16e1 100644
--- a/src/mongo/db/pipeline/document_source_change_stream.h
+++ b/src/mongo/db/pipeline/document_source_change_stream.h
@@ -29,15 +29,12 @@
 
 #pragma once
 
-#include <type_traits>
-
 #include "mongo/db/pipeline/document_source.h"
 #include "mongo/db/pipeline/document_source_change_stream_gen.h"
 #include "mongo/db/pipeline/document_source_match.h"
 #include "mongo/db/pipeline/document_source_single_document_transformation.h"
 #include "mongo/db/pipeline/field_path.h"
 #include "mongo/db/pipeline/resume_token.h"
-#include "mongo/util/intrusive_counter.h"
 
 namespace mongo {
 
@@ -213,12 +210,6 @@ private:
  */
 class DocumentSourceOplogMatch final : public DocumentSourceMatch {
 public:
-    DocumentSourceOplogMatch(const DocumentSourceOplogMatch& other) : DocumentSourceMatch(other) {}
-
-    virtual boost::intrusive_ptr<DocumentSourceMatch> clone() const {
-        return make_intrusive<std::decay_t<decltype(*this)>>(*this);
-    }
-
     static boost::intrusive_ptr<DocumentSourceOplogMatch> create(
         BSONObj filter, const boost::intrusive_ptr<ExpressionContext>& expCtx);
 
@@ -237,7 +228,7 @@ public:
     Value serialize(boost::optional<ExplainOptions::Verbosity> explain) const final;
 
 private:
-    using DocumentSourceMatch::DocumentSourceMatch;
+    DocumentSourceOplogMatch(BSONObj filter, const boost::intrusive_ptr<ExpressionContext>& expCtx);
 };
 
 }  // namespace mongo
diff --git a/src/mongo/db/pipeline/document_source_list_sessions.h b/src/mongo/db/pipeline/document_source_list_sessions.h
index ed8dcdf177d..86ee7c543fe 100644
--- a/src/mongo/db/pipeline/document_source_list_sessions.h
+++ b/src/mongo/db/pipeline/document_source_list_sessions.h
@@ -29,13 +29,10 @@
 
 #pragma once
 
-#include <type_traits>
-
 #include "mongo/bson/bsonelement.h"
 #include "mongo/db/pipeline/document_source_list_local_sessions.h"
 #include "mongo/db/pipeline/document_source_match.h"
 #include "mongo/db/pipeline/lite_parsed_document_source.h"
-#include "mongo/util/intrusive_counter.h"
 
 namespace mongo {
 
@@ -50,13 +47,6 @@ namespace mongo {
  */
 class DocumentSourceListSessions final : public DocumentSourceMatch {
 public:
-    DocumentSourceListSessions(const DocumentSourceListSessions& other)
-        : DocumentSourceMatch(other) {}
-
-    virtual boost::intrusive_ptr<DocumentSourceMatch> clone() const {
-        return make_intrusive<std::decay_t<decltype(*this)>>(*this);
-    }
-
     static constexpr StringData kStageName = "$listSessions"_sd;
 
     class LiteParsed final : public LiteParsedDocumentSource {
diff --git a/src/mongo/db/pipeline/document_source_match.h b/src/mongo/db/pipeline/document_source_match.h
index ecdda5dc274..a684c4c82f8 100644
--- a/src/mongo/db/pipeline/document_source_match.h
+++ b/src/mongo/db/pipeline/document_source_match.h
@@ -30,24 +30,16 @@
 #pragma once
 
 #include <memory>
-#include <type_traits>
 #include <utility>
 
 #include "mongo/client/connpool.h"
 #include "mongo/db/matcher/matcher.h"
 #include "mongo/db/pipeline/document_source.h"
-#include "mongo/util/intrusive_counter.h"
 
 namespace mongo {
 
 class DocumentSourceMatch : public DocumentSource {
 public:
-    template <typename T, typename... Args, typename>
-    friend boost::intrusive_ptr<T> make_intrusive(Args&&...);
-    virtual boost::intrusive_ptr<DocumentSourceMatch> clone() const {
-        return make_intrusive<std::decay_t<decltype(*this)>>(*this);
-    }
-
     static constexpr StringData kStageName = "$match"_sd;
     /**
      * Convenience method for creating a $match stage.
@@ -178,11 +170,6 @@ public:
     }
 
 protected:
-    DocumentSourceMatch(const DocumentSourceMatch& other)
-        : DocumentSourceMatch(
-              other.serialize().getDocument().toBson().firstElement().embeddedObject(),
-              other.pExpCtx) {}
-
     GetNextResult doGetNext() override;
     DocumentSourceMatch(const BSONObj& query,
                         const boost::intrusive_ptr<ExpressionContext>& expCtx);
diff --git a/src/mongo/db/pipeline/document_source_single_document_transformation.h b/src/mongo/db/pipeline/document_source_single_document_transformation.h
index d983de72021..323c628f60e 100644
--- a/src/mongo/db/pipeline/document_source_single_document_transformation.h
+++ b/src/mongo/db/pipeline/document_source_single_document_transformation.h
@@ -29,8 +29,6 @@
 
 #pragma once
 
-#include <type_traits>
-
 #include "mongo/db/pipeline/document_source.h"
 #include "mongo/db/pipeline/transformer_interface.h"
 
@@ -44,12 +42,6 @@ namespace mongo {
  */
 class DocumentSourceSingleDocumentTransformation final : public DocumentSource {
 public:
-    virtual boost::intrusive_ptr<DocumentSource> clone() const {
-        auto list = DocumentSource::parse(pExpCtx, serialize().getDocument().toBson());
-        invariant(list.size() == 1);
-        return list.front();
-    }
-
     DocumentSourceSingleDocumentTransformation(
         const boost::intrusive_ptr<ExpressionContext>& pExpCtx,
         std::unique_ptr<TransformerInterface> parsedTransform,
diff --git a/src/mongo/db/pipeline/document_source_union_with.cpp b/src/mongo/db/pipeline/document_source_union_with.cpp
index 00f531bbf8d..a6a31657dbf 100644
--- a/src/mongo/db/pipeline/document_source_union_with.cpp
+++ b/src/mongo/db/pipeline/document_source_union_with.cpp
@@ -32,18 +32,15 @@
 
 #include <iterator>
 
-#include "mongo/db/commands/test_commands_enabled.h"
-#include "mongo/db/pipeline/document_source_match.h"
-#include "mongo/db/pipeline/document_source_single_document_transformation.h"
 #include "mongo/db/pipeline/document_source_union_with.h"
 #include "mongo/db/pipeline/document_source_union_with_gen.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
 
-REGISTER_DOCUMENT_SOURCE(unionWith,
-                         DocumentSourceUnionWith::LiteParsed::parse,
-                         DocumentSourceUnionWith::createFromBson);
+REGISTER_TEST_DOCUMENT_SOURCE(unionWith,
+                              DocumentSourceUnionWith::LiteParsed::parse,
+                              DocumentSourceUnionWith::createFromBson);
 
 namespace {
 std::unique_ptr<Pipeline, PipelineDeleter> buildPipelineFromViewDefinition(
@@ -119,9 +116,6 @@ PrivilegeVector DocumentSourceUnionWith::LiteParsed::requiredPrivileges(
 
 boost::intrusive_ptr<DocumentSource> DocumentSourceUnionWith::createFromBson(
     BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
-    uassert(ErrorCodes::NotImplemented,
-            "$unionWith can only be used if test commands are enabled",
-            getTestCommandsEnabled());
     uassert(ErrorCodes::FailedToParse,
             str::stream()
                 << "the $unionWith stage specification must be an object or string, but found "
@@ -169,23 +163,12 @@ DocumentSource::GetNextResult DocumentSourceUnionWith::doGetNext() {
     return GetNextResult::makeEOF();
 }
 
-Pipeline::SourceContainer::iterator DocumentSourceUnionWith::doOptimizeAt(
-    Pipeline::SourceContainer::iterator itr, Pipeline::SourceContainer* container) {
-    auto duplicateAcrossUnion = [&](auto&& nextStage) {
-        _pipeline->addFinalSource(nextStage->clone());
-        auto newStageItr = container->insert(itr, std::move(nextStage));
-        container->erase(std::next(itr));
-        return newStageItr == container->begin() ? newStageItr : std::prev(newStageItr);
-    };
-    if (std::next(itr) != container->end()) {
-        if (auto nextMatch = dynamic_cast<DocumentSourceMatch*>((*std::next(itr)).get()))
-            return duplicateAcrossUnion(nextMatch);
-        else if (auto nextProject = dynamic_cast<DocumentSourceSingleDocumentTransformation*>(
-                     (*std::next(itr)).get()))
-            return duplicateAcrossUnion(nextProject);
-    }
-    return std::next(itr);
-};
+DocumentSource::GetModPathsReturn DocumentSourceUnionWith::getModifiedPaths() const {
+    // Since we might have a document arrive from the foreign pipeline with the same path as a
+    // document in the main pipeline. Without introspecting the sub-pipeline, we must report that
+    // all paths have been modified.
+    return {GetModPathsReturn::Type::kAllPaths, {}, {}};
+}
 
 void DocumentSourceUnionWith::doDispose() {
     if (_pipeline) {
diff --git a/src/mongo/db/pipeline/document_source_union_with.h b/src/mongo/db/pipeline/document_source_union_with.h
index beb69c7e9e5..ba0327a4be2 100644
--- a/src/mongo/db/pipeline/document_source_union_with.h
+++ b/src/mongo/db/pipeline/document_source_union_with.h
@@ -80,15 +80,10 @@ public:
         std::vector<Value>& array,
         boost::optional<ExplainOptions::Verbosity> explain = boost::none) const final;
 
-    GetModPathsReturn getModifiedPaths() const final {
-        // Since we might have a document arrive from the foreign pipeline with the same path as a
-        // document in the main pipeline. Without introspecting the sub-pipeline, we must report
-        // that all paths have been modified.
-        return {GetModPathsReturn::Type::kAllPaths, {}, {}};
-    }
+    GetModPathsReturn getModifiedPaths() const final;
 
     StageConstraints constraints(Pipeline::SplitState) const final {
-        auto constraints = StageConstraints(
+        return StageConstraints(
             StreamType::kStreaming,
             PositionRequirement::kNone,
             HostTypeRequirement::kAnyShard,
@@ -99,13 +94,6 @@ public:
             // outside of the constraints as long as the involved namespaces are reported correctly.
             LookupRequirement::kAllowed,
             UnionRequirement::kAllowed);
-
-        // DocumentSourceUnionWith cannot directly swap with match but it contains custom logic in
-        // the doOptimizeAt() member function to allow itself to duplicate any match ahead in the
-        // current pipeline and place one copy inside its sub-pipeline and one copy behind in the
-        // current pipeline.
-        constraints.canSwapWithMatch = false;
-        return constraints;
     }
 
     DepsTracker::State getDependencies(DepsTracker* deps) const final;
@@ -123,15 +111,6 @@ public:
 
 protected:
     GetNextResult doGetNext() final;
-
-    Pipeline::SourceContainer::iterator doOptimizeAt(Pipeline::SourceContainer::iterator itr,
-                                                     Pipeline::SourceContainer* container) final;
-
-    boost::intrusive_ptr<DocumentSource> optimize() final {
-        _pipeline->optimizePipeline();
-        return this;
-    }
-
     void doDispose() final;
 
 private:
diff --git a/src/mongo/db/pipeline/pipeline_test.cpp b/src/mongo/db/pipeline/pipeline_test.cpp
index 06e3c06923f..5cc39e890bf 100644
--- a/src/mongo/db/pipeline/pipeline_test.cpp
+++ b/src/mongo/db/pipeline/pipeline_test.cpp
@@ -1853,160 +1853,6 @@ TEST(PipelineOptimizationTest, SortSkipProjSkipLimSkipLimBecomesTopKSortSkipProj
     assertPipelineOptimizesAndSerializesTo(inputPipe, outputPipe, serializedPipe);
 }
 
-TEST(PipelineOptimizationTest, MatchGetsPushedIntoBothChildrenOfUnion) {
-    setTestCommandsEnabled(true);  // TODO SERVER-45712 remove this line.
-    assertPipelineOptimizesTo(
-        "["
-        " {$unionWith: 'coll'},"
-        " {$match: {x: {$eq: 2}}}"
-        "]",
-        "[{$match: {x: {$eq: 2}}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$match: {x: {$eq: 2}}}]"
-        " }}]");
-
-    // Test that the $match can get pulled forward through other stages.
-    assertPipelineOptimizesAndSerializesTo(
-        "["
-        " {$unionWith: 'coll'},"
-        " {$lookup: {from: 'lookupColl', as: 'y', localField: 'z', foreignField: 'z'}},"
-        " {$sort: {score: 1}},"
-        " {$match: {x: {$eq: 2}}}"
-        "]",
-        "["
-        " {$match: {x: {$eq: 2}}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$match: {x: {$eq: 2}}}]"
-        " }},"
-        " {$lookup: {from: 'lookupColl', as: 'y', localField: 'z', foreignField: 'z'}},"
-        " {$sort: {sortKey: {score: 1}}}"
-        "]",
-        "["
-        " {$match: {x: {$eq: 2}}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$match: {x: {$eq: 2}}}]"
-        " }},"
-        " {$lookup: {from: 'lookupColl', as: 'y', localField: 'z', foreignField: 'z'}},"
-        " {$sort: {score: 1}}"
-        "]");
-
-    // Test that the $match can get pulled forward from after the $unionWith to inside, then to the
-    // beginning of a $unionWith subpipeline.
-    // TODO: SERVER-45535 the explained inner pipeline should have the 'sortKey' form for $sort.
-    assertPipelineOptimizesAndSerializesTo(
-        "["
-        " {$unionWith: {"
-        "    coll: 'coll',"
-        "    pipeline: ["
-        "      {$project: {y: false}},"
-        "      {$sort: {score: 1}}"
-        "    ]"
-        " }},"
-        " {$match: {x: {$eq: 2}}}"
-        "]",
-        "["
-        " {$match: {x: {$eq: 2}}},"
-        " {$unionWith: {"
-        "    coll: 'coll',"
-        "    pipeline: ["
-        "      {$match: {x: {$eq: 2}}},"
-        "      {$project: {y: false}},"
-        "      {$sort: {score: 1}}"
-        "    ]"
-        " }}"
-        "]",
-        "["
-        " {$match: {x: {$eq: 2}}},"
-        " {$unionWith: {"
-        "    coll: 'coll',"
-        "    pipeline: ["
-        "      {$match: {x: {$eq: 2}}},"
-        "      {$project: {y: false}},"
-        "      {$sort: {score: 1}}"
-        "    ]"
-        " }}"
-        "]");
-}
-
-TEST(PipelineOptimizationTest, ProjectGetsPushedIntoBothChildrenOfUnion) {
-    setTestCommandsEnabled(true);  // TODO SERVER-45712 remove this line.
-    assertPipelineOptimizesTo(
-        "["
-        " {$unionWith: 'coll'},"
-        " {$project: {x: false}}"
-        "]",
-        "[{$project: {x: false}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$project: {x: false}}]"
-        " }}]");
-
-    // Test an inclusion projection.
-    assertPipelineOptimizesTo(
-        "["
-        " {$unionWith: 'coll'},"
-        " {$project: {x: true}}"
-        "]",
-        "[{$project: {_id: true, x: true}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$project: {_id: true, x: true}}]"
-        " }}]");
-
-    // Test a $set.
-    assertPipelineOptimizesTo(
-        "["
-        " {$unionWith: 'coll'},"
-        " {$set: {x: 'new value'}}"
-        "]",
-        "[{$set: {x: {$const: 'new value'}}},"
-        " {$unionWith: {"
-        "   coll: 'coll',"
-        "   pipeline: [{$set: {x: {$const: 'new value'}}}]"
-        " }}]");
-}
-
-TEST(PipelineOptimizationTest, UnionWithViewsSampleUseCase) {
-    setTestCommandsEnabled(true);  // TODO SERVER-45712 remove this line.
-    // Test that if someone uses $unionWith to query one logical collection from four physical
-    // collections then the query and projection can get pushed down to next to each collection
-    // access.
-    assertPipelineOptimizesTo(
-        "["
-        " {$unionWith: 'Q2'},"
-        " {$unionWith: 'Q3'},"
-        " {$unionWith: 'Q4'},"
-        " {$match: {business: {$eq: 'good'}}},"
-        " {$project: {_id: true, x: true}}"
-        "]",
-        "[{$match: {business: {$eq: 'good'}}},"
-        " {$project: {_id: true, x: true}},"
-        " {$unionWith: {"
-        "   coll: 'Q2',"
-        "   pipeline: ["
-        "     {$match: {business: {$eq: 'good'}}},"
-        "     {$project: {_id: true, x: true}}"
-        "   ]"
-        " }},"
-        " {$unionWith: {"
-        "   coll: 'Q3',"
-        "   pipeline: ["
-        "     {$match: {business: {$eq: 'good'}}},"
-        "     {$project: {_id: true, x: true}}"
-        "   ]"
-        " }},"
-        " {$unionWith: {"
-        "   coll: 'Q4',"
-        "   pipeline: ["
-        "     {$match: {business: {$eq: 'good'}}},"
-        "     {$project: {_id: true, x: true}}"
-        "   ]"
-        " }}"
-        "]");
-}
 }  // namespace Local
 
 namespace Sharded {