Revert "SERVER-31447 Use correct collation for update lookup"

This reverts commit de0b16077945eb6b6ec161b99f41c3222aade3b8.

7 files changed, 30 insertions, 78 deletions

diff --git a/src/mongo/db/pipeline/document_source.h b/src/mongo/db/pipeline/document_source.h
index 0ecd0fcf92a..2f6bec9fbcc 100644
--- a/src/mongo/db/pipeline/document_source.h
+++ b/src/mongo/db/pipeline/document_source.h
@@ -841,15 +841,13 @@ public:
         virtual std::vector<FieldPath> collectDocumentKeyFields(UUID) const = 0;
 
         /**
-         * Returns zero or one documents with the document key 'documentKey'. 'documentKey' is
-         * treated as a unique identifier of a document, and may include an _id or all fields from
-         * the shard key and an _id. Throws if more than one match was found. Returns boost::none if
-         * no matching documents were found, including cases where the given namespace does not
-         * exist.
+         * Returns zero or one documents matching the input filter, or throws if more than one match
+         * was found. The passed ExpressionContext may use a different namespace than the
+         * ExpressionContext used to construct the MongoProcessInterface. Returns boost::none if no
+         * matching documents were found, including cases where the given namespace does not exist.
          */
-        virtual boost::optional<Document> lookupSingleDocument(const NamespaceString& nss,
-                                                               UUID collectionUUID,
-                                                               const Document& documentKey) = 0;
+        virtual boost::optional<Document> lookupSingleDocument(
+            const boost::intrusive_ptr<ExpressionContext>& expCtx, const Document& filter) = 0;
 
         /**
          * Returns a vector of all local cursors.
diff --git a/src/mongo/db/pipeline/document_source_lookup_change_post_image.cpp b/src/mongo/db/pipeline/document_source_lookup_change_post_image.cpp
index 7752fbfd751..058a959f588 100644
--- a/src/mongo/db/pipeline/document_source_lookup_change_post_image.cpp
+++ b/src/mongo/db/pipeline/document_source_lookup_change_post_image.cpp
@@ -105,9 +105,10 @@ Value DocumentSourceLookupChangePostImage::lookupPostImage(const Document& updat
     auto resumeToken =
         ResumeToken::parse(updateOp[DocumentSourceChangeStream::kIdField].getDocument());
 
-    invariant(resumeToken.getData().uuid);
-    auto lookedUpDoc =
-        _mongoProcessInterface->lookupSingleDocument(nss, *resumeToken.getData().uuid, documentKey);
+    // TODO SERVER-29134 we need to extract the namespace from the document and set them on the new
+    // ExpressionContext if we're getting notifications from an entire database.
+    auto foreignExpCtx = pExpCtx->copyWith(nss, resumeToken.getData().uuid);
+    auto lookedUpDoc = _mongoProcessInterface->lookupSingleDocument(foreignExpCtx, documentKey);
 
     // Check whether the lookup returned any documents. Even if the lookup itself succeeded, it may
     // not have returned any results if the document was deleted in the time since the update op.
diff --git a/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp b/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
index 3d35f875619..05b92297359 100644
--- a/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
+++ b/src/mongo/db/pipeline/document_source_lookup_change_post_image_test.cpp
@@ -113,11 +113,9 @@ public:
         return Status::OK();
     }
 
-    boost::optional<Document> lookupSingleDocument(const NamespaceString& nss,
-                                                   UUID collectionUUID,
-                                                   const Document& documentKey) {
-        boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest(nss));
-        auto swPipeline = makePipeline({BSON("$match" << documentKey)}, expCtx);
+    boost::optional<Document> lookupSingleDocument(
+        const boost::intrusive_ptr<ExpressionContext>& expCtx, const Document& filter) {
+        auto swPipeline = makePipeline({BSON("$match" << filter)}, expCtx);
         if (swPipeline == ErrorCodes::NamespaceNotFound) {
             return boost::none;
         }
@@ -126,12 +124,11 @@ public:
         auto lookedUpDocument = pipeline->getNext();
         if (auto next = pipeline->getNext()) {
             uasserted(ErrorCodes::TooManyMatchingDocuments,
-                      str::stream() << "found more than one document matching "
-                                    << documentKey.toString()
+                      str::stream() << "found more than one document matching " << filter.toString()
                                     << " ["
-                                    << lookedUpDocument->toString()
+                                    << (*lookedUpDocument).toString()
                                     << ", "
-                                    << next->toString()
+                                    << (*next).toString()
                                     << "]");
         }
         return lookedUpDocument;
diff --git a/src/mongo/db/pipeline/expression_context.cpp b/src/mongo/db/pipeline/expression_context.cpp
index e2b2e1e758d..64c813ed5a4 100644
--- a/src/mongo/db/pipeline/expression_context.cpp
+++ b/src/mongo/db/pipeline/expression_context.cpp
@@ -29,7 +29,6 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/pipeline/expression_context.h"
-#include "mongo/db/query/collation/collation_spec.h"
 #include "mongo/db/query/collation/collator_factory_interface.h"
 
 namespace mongo {
@@ -122,10 +121,8 @@ void ExpressionContext::setCollator(const CollatorInterface* collator) {
     _valueComparator = ValueComparator(_collator);
 }
 
-intrusive_ptr<ExpressionContext> ExpressionContext::copyWith(
-    NamespaceString ns,
-    boost::optional<UUID> uuid,
-    boost::optional<std::unique_ptr<CollatorInterface>> collator) const {
+intrusive_ptr<ExpressionContext> ExpressionContext::copyWith(NamespaceString ns,
+                                                             boost::optional<UUID> uuid) const {
     intrusive_ptr<ExpressionContext> expCtx =
         new ExpressionContext(std::move(ns), timeZoneDatabase);
 
@@ -143,17 +140,11 @@ intrusive_ptr<ExpressionContext> ExpressionContext::copyWith(
 
     expCtx->opCtx = opCtx;
 
-    if (collator) {
-        expCtx->collation =
-            *collator ? (*collator)->getSpec().toBSON() : CollationSpec::kSimpleSpec;
-        expCtx->setCollator(std::move(*collator));
-    } else {
-        expCtx->collation = collation;
-        if (_ownedCollator) {
-            expCtx->setCollator(_ownedCollator->clone());
-        } else if (_collator) {
-            expCtx->setCollator(_collator);
-        }
+    expCtx->collation = collation;
+    if (_ownedCollator) {
+        expCtx->setCollator(_ownedCollator->clone());
+    } else if (_collator) {
+        expCtx->setCollator(_collator);
     }
 
     expCtx->_resolvedNamespaces = _resolvedNamespaces;
diff --git a/src/mongo/db/pipeline/expression_context.h b/src/mongo/db/pipeline/expression_context.h
index a2e16163a73..59e85edfe90 100644
--- a/src/mongo/db/pipeline/expression_context.h
+++ b/src/mongo/db/pipeline/expression_context.h
@@ -140,9 +140,7 @@ public:
      * separate aggregation pipeline on 'ns' with the optional 'uuid'.
      */
     boost::intrusive_ptr<ExpressionContext> copyWith(
-        NamespaceString ns,
-        boost::optional<UUID> uuid = boost::none,
-        boost::optional<std::unique_ptr<CollatorInterface>> collator = boost::none) const;
+        NamespaceString ns, boost::optional<UUID> uuid = boost::none) const;
 
     /**
      * Returns the ResolvedNamespace corresponding to 'nss'. It is an error to call this method on a
diff --git a/src/mongo/db/pipeline/pipeline_d.cpp b/src/mongo/db/pipeline/pipeline_d.cpp
index b32f18828d0..d0acba8fb5f 100644
--- a/src/mongo/db/pipeline/pipeline_d.cpp
+++ b/src/mongo/db/pipeline/pipeline_d.cpp
@@ -384,14 +384,9 @@ public:
         return result;
     }
 
-    boost::optional<Document> lookupSingleDocument(const NamespaceString& nss,
-                                                   UUID collectionUUID,
-                                                   const Document& documentKey) final {
-        // Be sure to do the lookup using the collection default collation.
-        auto foreignExpCtx =
-            _ctx->copyWith(nss, collectionUUID, _getCollectionDefaultCollator(nss, collectionUUID));
-        auto swPipeline = makePipeline({BSON("$match" << documentKey)}, foreignExpCtx);
-
+    boost::optional<Document> lookupSingleDocument(const intrusive_ptr<ExpressionContext>& expCtx,
+                                                   const Document& filter) final {
+        auto swPipeline = makePipeline({BSON("$match" << filter)}, expCtx);
         if (swPipeline == ErrorCodes::NamespaceNotFound) {
             return boost::none;
         }
@@ -400,8 +395,7 @@ public:
         auto lookedUpDocument = pipeline->getNext();
         if (auto next = pipeline->getNext()) {
             uasserted(ErrorCodes::TooManyMatchingDocuments,
-                      str::stream() << "found more than one document with document key "
-                                    << documentKey.toString()
+                      str::stream() << "found more than one document matching " << filter.toString()
                                     << " ["
                                     << lookedUpDocument->toString()
                                     << ", "
@@ -416,34 +410,8 @@ public:
     }
 
 private:
-    /**
-     * Looks up the collection default collator for the collection given by 'collectionUUID'. A
-     * collection's default collation is not allowed to change, so we cache the result to allow for
-     * quick lookups in the future. Looks up the collection by UUID, and returns 'nullptr' if the
-     * collection does not exist or if the collection's default collation is the simple collation.
-     */
-    std::unique_ptr<CollatorInterface> _getCollectionDefaultCollator(const NamespaceString& nss,
-                                                                     UUID collectionUUID) {
-        if (_collatorCache.find(collectionUUID) == _collatorCache.end()) {
-            AutoGetCollection autoColl(_ctx->opCtx, nss, collectionUUID, MODE_IS);
-            if (!autoColl.getCollection()) {
-                // This collection doesn't exist - since we looked up by UUID, it will never exist
-                // in the future, so we cache a null pointer as the default collation.
-                _collatorCache[collectionUUID] = nullptr;
-            } else {
-                auto defaultCollator = autoColl.getCollection()->getDefaultCollator();
-                // Clone the collator so that we can safely use the pointer if the collection
-                // disappears right after we release the lock.
-                _collatorCache[collectionUUID] =
-                    defaultCollator ? defaultCollator->clone() : nullptr;
-            }
-        }
-        return _collatorCache[collectionUUID] ? _collatorCache[collectionUUID]->clone() : nullptr;
-    }
-
     intrusive_ptr<ExpressionContext> _ctx;
     DBDirectClient _client;
-    std::map<UUID, std::unique_ptr<const CollatorInterface>> _collatorCache;
 };
 
 /**
diff --git a/src/mongo/db/pipeline/stub_mongo_process_interface.h b/src/mongo/db/pipeline/stub_mongo_process_interface.h
index c0beb0504ba..1414289ed67 100644
--- a/src/mongo/db/pipeline/stub_mongo_process_interface.h
+++ b/src/mongo/db/pipeline/stub_mongo_process_interface.h
@@ -118,9 +118,8 @@ public:
         MONGO_UNREACHABLE;
     }
 
-    boost::optional<Document> lookupSingleDocument(const NamespaceString& nss,
-                                                   UUID collectionUUID,
-                                                   const Document& documentKey) {
+    boost::optional<Document> lookupSingleDocument(
+        const boost::intrusive_ptr<ExpressionContext>& expCtx, const Document& filter) {
         MONGO_UNREACHABLE;
     }