SERVER-53675 Allow validate to fix up multikey metadata

This allows foreground validation to fix up the following multikey
metadata inconsistencies:

* An index is multikey but there are no multikey fields
* An index has multikeyPaths covering fields that are not multikey
* An index does not have multikeyPaths but there are multikey documents (for pre-3.4 indexes)

If any changes were made, a warning is included to the validate output
and the 'repaired' flag is set to true.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/mongo/db/catalog/collection_validation.cpp b/src/mongo/db/catalog/collection_validation.cpp
index f47813abef7..241f9fe4f05 100644
--- a/src/mongo/db/catalog/collection_validation.cpp
+++ b/src/mongo/db/catalog/collection_validation.cpp
@@ -220,7 +220,7 @@ void _gatherIndexEntryErrors(OperationContext* opCtx,
                                    << " extra index entries.");
     }
 
-    if (validateState->shouldRunRepair()) {
+    if (validateState->fixErrors()) {
         indexConsistency->repairMissingIndexEntries(opCtx, result);
     }
 
@@ -460,15 +460,17 @@ Status validate(OperationContext* opCtx,
         opCtx->recoveryUnit()->abandonSnapshot();
         opCtx->recoveryUnit()->setPrepareConflictBehavior(oldPrepareConflictBehavior);
     });
-    if (validateState.shouldRunRepair()) {
+    if (validateState.fixErrors()) {
         // Note: cannot set PrepareConflictBehavior here, since the validate command with repair
         // needs kIngnoreConflictsAllowWrites, but validate repair at startup cannot set that here
         // due to an already active WriteUnitOfWork.  The prepare conflict behavior for validate
         // command with repair is set in the command code prior to this point.
         invariant(!validateState.isBackground());
     } else if (!validateState.isBackground()) {
+        // Foreground validation may perform writes to fix up inconsistencies that are not
+        // correctness errors.
         opCtx->recoveryUnit()->setPrepareConflictBehavior(
-            PrepareConflictBehavior::kIgnoreConflicts);
+            PrepareConflictBehavior::kIgnoreConflictsAllowWrites);
     } else {
         // isBackground().
         invariant(oldPrepareConflictBehavior == PrepareConflictBehavior::kEnforce);