diff options
Diffstat (limited to 'src/mongo/db/pipeline/expression_js_emit.cpp')
| -rw-r--r-- | src/mongo/db/pipeline/expression_js_emit.cpp | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/src/mongo/db/pipeline/expression_js_emit.cpp b/src/mongo/db/pipeline/expression_js_emit.cpp index d19a9c53191..ca6ba238c6e 100644 --- a/src/mongo/db/pipeline/expression_js_emit.cpp +++ b/src/mongo/db/pipeline/expression_js_emit.cpp @@ -145,11 +145,14 @@ Value ExpressionInternalJsEmit::evaluate(const Document& root, Variables* variab ExpressionContext* expCtx = getExpressionContext(); auto jsExec = expCtx->getJsExecWithScope(); - // Inject the native "emit" function to be called from the user-defined map function. This - // particular Expression/ExpressionContext may be reattached to a new OperationContext (and thus - // a new JS Scope) when used across getMore operations, so this method will handle that case for - // us by only injecting if we haven't already. - jsExec->injectEmitIfNecessary(emitFromJS, &_emitState); + + // Inject the native "emit" function to be called from the user-defined map function. + // + // We reinject this function on every invocation of evaluate(), because there is a single + // JsExecution instance for the OperationContext, which may be shared by multiple aggregation + // pipelines and we need to ensure that the injected function still points to the valid + // contextual data ('_emitState'). + jsExec->injectEmit(emitFromJS, &_emitState); // Although inefficient to "create" a new function every time we evaluate, this will usually end // up being a simple cache lookup. This is needed because the JS Scope may have been recreated |