SERVER-40267 Clean up debug string generation for MatchExpression.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/mongo/db/matcher/expression.h b/src/mongo/db/matcher/expression.h
index 0fb0a2060b4..9607dce1963 100644
--- a/src/mongo/db/matcher/expression.h
+++ b/src/mongo/db/matcher/expression.h
@@ -309,8 +309,20 @@ public:
     //
     // Debug information
     //
-    virtual std::string toString() const;
-    virtual void debugString(StringBuilder& debug, int level = 0) const = 0;
+
+    /**
+     * Returns a debug string representing the match expression tree, including any tags attached
+     * for planning. This debug string format may spill across multiple lines, so it is not suitable
+     * for logging at low debug levels or for error messages.
+     */
+    std::string debugString() const;
+    virtual void debugString(StringBuilder& debug, int indentationLevel = 0) const = 0;
+
+    /**
+     * Serializes this MatchExpression to BSON, and then returns a standard string representation of
+     * the resulting BSON object.
+     */
+    std::string toString() const;
 
 protected:
     /**
@@ -330,7 +342,7 @@ protected:
 
     virtual void _doAddDependencies(DepsTracker* deps) const {}
 
-    void _debugAddSpace(StringBuilder& debug, int level) const;
+    void _debugAddSpace(StringBuilder& debug, int indentationLevel) const;
 
 private:
     /**