nocfbot-0027-Fix-comment-typos-grammar.txt

From 809e8b5c9f79e40ee114bef963e2a902800608ed Mon Sep 17 00:00:00 2001
From: Henson Choi <assam258@gmail.com>
Date: Tue, 7 Apr 2026 10:09:41 +0900
Subject: [PATCH 27/40] Fix comment typos, grammar, and inaccuracies in RPR
 code

---
 src/backend/executor/execRPR.c          |  7 +++----
 src/backend/executor/nodeWindowAgg.c    | 20 ++++++++++----------
 src/backend/optimizer/plan/createplan.c |  3 ++-
 3 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/src/backend/executor/execRPR.c b/src/backend/executor/execRPR.c
index 94f1b2941a2..baee45ce54e 100644
--- a/src/backend/executor/execRPR.c
+++ b/src/backend/executor/execRPR.c
@@ -416,7 +416,6 @@
  * the normal loop-back (which cycle detection will eventually kill) and
  * a fast-forward exit clone that bypasses the loop entirely.
  * (See IX-4(c) for detailed runtime behavior.)
- *     - Empty match is impossible since body is not nullable
  *
  * IV-5. Absorbability Analysis (RPR_ELEM_ABSORBABLE)
  *
@@ -645,8 +644,8 @@
  * When processing a context whose matchStartRow differs from the shared
  * value, nfa_reevaluate_dependent_vars() temporarily sets nav_match_start
  * to that context's matchStartRow and re-evaluates only the dependent
- * variables.  No restore is needed because contexts are ordered by
- * matchStartRow (ascending), so no later context shares the head's value.
+ * variables.  The original nav_match_start and currentpos are saved and
+ * restored after re-evaluation.
  *
  * VI-5. Tuplestore Mark and Trim (nodeWindowAgg.c)
  *
@@ -2715,7 +2714,7 @@ nfa_advance_var(WindowAggState *winstate, RPRNFAContext *ctx,
 		bool		reluctant = RPRElemIsReluctant(elem);
 
 		/*
-		 * Clone state for the second-priority path. For greedy, clone is the
+		 * Clone state for the first-priority path. For greedy, clone is the
 		 * loop state; for reluctant, clone is the exit state.
 		 */
 		if (reluctant)
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index cdbe356abd7..849ebf8abb0 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -3705,8 +3705,8 @@ ignorenulls_getfuncarginframe(WindowObject winobj, int argno,
 	{
 		/*
 		 * Early check if row could be out of reduced frame.  When RPR is
-		 * enabled, EXCUDE clause cannot be specified and the frame is always
-		 * contiguous.  So we can do the check followings safely. Note,
+		 * enabled, EXCLUDE clause cannot be specified and the frame is always
+		 * contiguous.  So we can safely perform the following checks. Note,
 		 * however, it is possible that a row is out of reduced frame if
 		 * there's a NULL in the middle. So we need to check it in the
 		 * following do loop.
@@ -4168,7 +4168,7 @@ eval_nav_first_offset(WindowAggState *winstate, List *defineClause)
 
 /*
  * rpr_is_defined
- * return true if Row pattern recognition is defined.
+ * Return true if row pattern recognition is defined.
  */
 static bool
 rpr_is_defined(WindowAggState *winstate)
@@ -4182,14 +4182,14 @@ rpr_is_defined(WindowAggState *winstate)
  * Determine whether a row is in the current row's reduced window frame
  * according to row pattern matching
  *
- * The row must has been already determined that it is in a full window frame
- * and fetched it into slot.
+ * The row must have already been determined to be in a full window frame
+ * and fetched into the slot.
  *
  * Returns:
  * = 0, RPR is not defined.
  * >0, if the row is the first in the reduced frame. Return the number of rows
  * in the reduced frame.
- * -1, if the row is unmatched row
+ * -1, if the row is an unmatched row
  * -2, if the row is in the reduced frame but needed to be skipped because of
  * AFTER MATCH SKIP PAST LAST ROW
  * -----------------
@@ -4204,8 +4204,8 @@ row_is_in_reduced_frame(WindowObject winobj, int64 pos)
 	if (!rpr_is_defined(winstate))
 	{
 		/*
-		 * RPR is not defined. Assume that we are always in the the reduced
-		 * window frame.
+		 * RPR is not defined. Assume that we are always in the reduced window
+		 * frame.
 		 */
 		rtn = 0;
 		return rtn;
@@ -4938,8 +4938,8 @@ WinGetFuncArgInFrame(WindowObject winobj, int argno,
  * isout: output argument, set to indicate whether target row position
  *		is out of frame (can pass NULL if caller doesn't care about this)
  *
- * Returns 0 if we successfully got the slot. false if out of frame.
- * (also isout is set)
+ * Returns 0 if we successfully got the slot, or nonzero if out of frame.
+ * (isout is also set in the latter case.)
  */
 static int
 WinGetSlotInFrame(WindowObject winobj, TupleTableSlot *slot,
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 02d511269ab..50668f3b7ab 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -2475,7 +2475,8 @@ typedef struct NavOffsetContext
 	int64		maxOffset;		/* max PREV/LAST backward offset (>= 0) */
 	bool		maxNeedsEval;	/* non-constant PREV/LAST offset found */
 	bool		maxOverflow;	/* constant offset overflow detected */
-	int64		firstOffset;	/* min FIRST offset (>= 0), or -1 if none */
+	int64		firstOffset;	/* min FIRST offset (may be negative for
+								 * PREV_FIRST) */
 	bool		hasFirst;		/* any FIRST node found */
 	bool		firstNeedsEval; /* non-constant FIRST offset found */
 } NavOffsetContext;
-- 
2.50.1 (Apple Git-155)