SERVER-43816 Push $text and $meta:"textScore" sort into the PlanStage layer.

This change involves unifying the behavior of find and
agg for validation of $meta:"textScore". In particular, find
operations no longer require a "textScore" $meta projection
in order to specify a "textScore" $meta sort. This brings
find into alignment with agg, which never had such a
restriction. It is also now legal for a find command to
sort on the field overridden by a $meta:"textScore" projection
without specifying the $meta operator in the sort pattern.

In addition:
 - Tightens validation around uses of "textScore" $meta
 projections for queries that do not specify a $text
 predicate.
 - Fixes a bug in which $natural sort/hint were not
 correctly validated.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/mongo/db/pipeline/dependencies.h b/src/mongo/db/pipeline/dependencies.h
index aab2e21bfb4..8b75439db53 100644
--- a/src/mongo/db/pipeline/dependencies.h
+++ b/src/mongo/db/pipeline/dependencies.h
@@ -162,10 +162,15 @@ struct DepsTracker {
     }
 
     /**
-     * Request that all metadata in the given QueryMetadataBitSet be added as dependencies.
+     * Request that all metadata in the given QueryMetadataBitSet be added as dependencies. Throws a
+     * UserException if any of the requested metadata fields have been marked as unavailable.
      */
     void requestMetadata(const QueryMetadataBitSet& metadata) {
-        _metadataDeps |= metadata;
+        for (size_t i = 1; i < DocumentMetadataFields::kNumFields; ++i) {
+            if (metadata[i]) {
+                setNeedsMetadata(static_cast<DocumentMetadataFields::MetaType>(i), true);
+            }
+        }
     }
 
     std::set<std::string> fields;    // Names of needed fields in dotted notation.