SERVER-25535 Remove injectExpressionContext().

These methods were formally used to propagate a new ExpressionContext to
stages, accumulators, or expressions which potentially needed to
comparisons. Originally, this was necessary since Pipeline parsing
happened outside of the collection lock and thus could not determine if
there was a default collation on the collection. This meant that the
collation could change after parsing and any operators that might
compare strings would need to know about it.

We have since moved parsing within the lock, so the collation can be
known at parse time and the ExpressionContext should not change. This
patch requires an ExpressionContext at construction time, and disallows
changing the collation on an ExpressionContext.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/mongo/db/pipeline/document_source_mock.cpp b/src/mongo/db/pipeline/document_source_mock.cpp
index 686f4ef6f2e..3918bbd5ad7 100644
--- a/src/mongo/db/pipeline/document_source_mock.cpp
+++ b/src/mongo/db/pipeline/document_source_mock.cpp
@@ -31,6 +31,8 @@
 #include "mongo/db/pipeline/document_source_mock.h"
 
 #include "mongo/db/pipeline/document.h"
+#include "mongo/db/pipeline/expression_context.h"
+#include "mongo/db/pipeline/expression_context_for_test.h"
 
 namespace mongo {
 
@@ -38,7 +40,7 @@ using boost::intrusive_ptr;
 using std::deque;
 
 DocumentSourceMock::DocumentSourceMock(deque<GetNextResult> results)
-    : DocumentSource(nullptr),
+    : DocumentSource(new ExpressionContextForTest()),
       queue(std::move(results)),
       sorts(SimpleBSONObjComparator::kInstance.makeBSONObjSet()) {}