Re: Fix \crosstabview to honor \pset display_true/display_false

> On Jun 25, 2026, at 21:21, Álvaro Herrera <alvherre@kurilemu.de> wrote:

Thank you very much for the comments.

> 
> On 2026-Jun-21, Chao Li wrote:
> 
>> Thank you both very much for reviewing and for the valuable comments.
>> 
>> I have made the helper private to crosstabview.c and left print.c
>> unchanged in v3. I will see if I can improve print.h/c for v20.
> 
> I mostly agree with this, but I don't think we need to make that
> function name that long.  It's a private function after all.  But it's
> definitely in the wrong spot in the file, so I propose to move it down.

Agreed.

> 
> Now, your new test case doesn't exercise "\pset null" under
> \crosstabview, and I'm not sure that just leaving the cell empty for a
> NULL is really the thing to do, when \pset null has set it to some other
> value.  Simply printing the \pset null string doesn't seem to cut it
> though (here implemented as the change in printCrosstab line 421ff), as
> seen in how this patch affects the test case prior to the new one.
> Should we have a separate array of bools to distinguish cells that must
> remain empty (because the query didn't provide a value for them) from
> cells that must have the \pset null value?
> 

Yes, I didn’t include \pset null in the new test case because I didn’t intend this patch to change NULL display behavior, so I assumed other test cases already covered that. I didn’t check that carefully enough.

I didn’t take this part from your proposal, so an empty cell still shows nothing:
```
@@ -442,7 +421,7 @@ printCrosstab(const PGresult *result,
	for (i = 0; i < cont.cellsadded; i++)
	{
		if (cont.cells[i] == NULL)
-			cont.cells[i] = "";
+			cont.cells[i] = printDisplayValue(&popt, InvalidOid, NULL, "");
	}
```

Your proposed test has NULL in the row and column headers, but not in the value column. I added a NULL value too, so the test case explicitly demonstrates the display difference between a NULL value and an empty cell.

PFA v4: addressed Álvaro's comments.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/