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2.25.2.0-b105

2.25.2.0-b105: [#26288] YSQL: Fix tuple-to-string utility functions
@arpang arpang tagged this 06 Mar 06:50 
Summary:
Tuple to string utility functions (YbHeapTupleToString(), YbHeapTupleToStringWithIsOmitted(), YbTupleTableSlotToStringWithIsOmitted()) have multiple issues:
- Code duplication across YbHeapTupleToString() and YbHeapTupleToStringWithIsOmitted()
- YbTupleTableSlotToStringWithIsOmitted() calls YbHeapTupleToStringWithIsOmitted(), but it should be the other way around.
     - Even the implementation is incorrect. YbTupleTableSlotToStringWithIsOmitted()  incorrectly asserts that `shouldFree` should be false. This is not the case for virtual and minimal tuple table slots.
     - `ExecFetchSlotHeapTuple()` expects the slot to be non-empty. YbTupleTableSlotToStringWithIsOmitted() doesn't make any such check before calling it.

Rework these functions.
Jira: DB-15633

Test Plan:
Manual tested the functions using the follwing patch:

```
diff --git a/src/postgres/src/backend/access/yb_access/yb_scan.c b/src/postgres/src/backend/access/yb_access/yb_scan.c
index b69b5830a6..698918b95d 100644
--- a/src/postgres/src/backend/access/yb_access/yb_scan.c
+++ b/src/postgres/src/backend/access/yb_access/yb_scan.c
@@ -4297,6 +4297,15 @@ ybFetchNext(YbcPgStatement handle, TupleTableSlot *slot, Oid relid)
 		TABLETUPLE_YBCTID(slot) = PointerGetDatum(syscols.ybctid);
 		slot->tts_tableOid = relid;
 	}
+	elog(INFO, "slot to string: %s", YbSlotToString(slot));
+	if (!TTS_EMPTY(slot))
+	{
+		bool free;
+		HeapTuple tuple = ExecFetchSlotHeapTuple(slot, false, &free);
+		elog(INFO, "heap tuple to string: %s", YbHeapTupleToString(tuple, slot->tts_tupleDescriptor));
+		if (free)
+			pfree(tuple);
+	}
 }

 /***************************************************************************

```

followed by:
```
select * from pg_class limit 1;
```

Reviewers: telgersma, fizaa, stiwary

Reviewed By: stiwary

Subscribers: yql

Differential Revision: https://phorge.dev.yugabyte.com/D42322
Assets 2
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