Make crosstabview honor boolean/null display settings

psql's \pset display_true/false settings, added by commit 645cb44,
affect normal query output, but not \crosstabview.  As a result, boolean
values used anywhere in crosstab output were always shown as "t" or "f",
which is inconsistent.  Change \crosstabview so that the configured
values are displayed instead.

While at it, make \crosstabview print the \pset null string, if any, in
cells for which the query produces a NULL value.  Cells for which the
query produces no value continue to have the empty string.  This is an
oversight in the aboriginal \crosstabview commit, c09b18f.

Add a regression test covering all of this.

Author: Chao Li <lic@highgo.com>
Reported-by: Chao Li <lic@highgo.com>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Backpatch: none needed
Discussion: https://postgr.es/m/B5E6F0A5-4B48-46D0-B5EB-CF8F8CC7D07D@gmail.com

Author: alvherre

src/bin/psql/crosstabview.c

@@ -7,6 +7,7 @@
  */
 #include "postgres_fe.h"
 
+#include "catalog/pg_type_d.h"
 #include "common.h"
 #include "common/int.h"
 #include "common/logging.h"
@@ -82,6 +83,8 @@ static bool printCrosstab(const PGresult *result,
 						  int num_columns, pivot_field *piv_columns, int field_for_columns,
 						  int num_rows, pivot_field *piv_rows, int field_for_rows,
 						  int field_for_data);
+static char *displayValue(char *value, Oid ftype, char *default_null);
+
 static void avlInit(avl_tree *tree);
 static void avlMergeValue(avl_tree *tree, char *name, char *sort_value);
 static int	avlCollectFields(avl_tree *tree, avl_node *node,
@@ -292,6 +295,9 @@ printCrosstab(const PGresult *result,
 				rn;
 	char		col_align;
 	int		   *horiz_map;
+	Oid			col_ftype = PQftype(result, field_for_columns);
+	Oid			row_ftype = PQftype(result, field_for_rows);
+	Oid			data_ftype = PQftype(result, field_for_data);
 	bool		retval = false;
 
 	printTableInit(&cont, &popt.topt, popt.title, num_columns + 1, num_rows);
@@ -302,8 +308,7 @@ printCrosstab(const PGresult *result,
 	printTableAddHeader(&cont,
 						PQfname(result, field_for_rows),
 						false,
-						column_type_alignment(PQftype(result,
-													  field_for_rows)));
+						column_type_alignment(row_ftype));
 
 	/*
 	 * To iterate over piv_columns[] by piv_columns[].rank, create a reverse
@@ -317,15 +322,13 @@ printCrosstab(const PGresult *result,
 	/*
 	 * The display alignment depends on its PQftype().
 	 */
-	col_align = column_type_alignment(PQftype(result, field_for_data));
+	col_align = column_type_alignment(data_ftype);
 
 	for (i = 0; i < num_columns; i++)
 	{
 		char	   *colname;
 
-		colname = piv_columns[horiz_map[i]].name ?
-			piv_columns[horiz_map[i]].name :
-			(popt.nullPrint ? popt.nullPrint : "");
+		colname = displayValue(piv_columns[horiz_map[i]].name, col_ftype, "");
 
 		printTableAddHeader(&cont, colname, false, col_align);
 	}
@@ -335,10 +338,9 @@ printCrosstab(const PGresult *result,
 	for (i = 0; i < num_rows; i++)
 	{
 		int			k = piv_rows[i].rank;
+		int			idx = k * (num_columns + 1);
 
-		cont.cells[k * (num_columns + 1)] = piv_rows[i].name ?
-			piv_rows[i].name :
-			(popt.nullPrint ? popt.nullPrint : "");
+		cont.cells[idx] = displayValue(piv_rows[i].name, row_ftype, "");
 	}
 	cont.cellsadded = num_rows * (num_columns + 1);
 
@@ -384,6 +386,7 @@ printCrosstab(const PGresult *result,
 		if (col_number >= 0 && row_number >= 0)
 		{
 			int			idx;
+			char	   *value;
 
 			/* index into the cont.cells array */
 			idx = 1 + col_number + row_number * (num_columns + 1);
@@ -394,16 +397,16 @@ printCrosstab(const PGresult *result,
 			if (cont.cells[idx] != NULL)
 			{
 				pg_log_error("\\crosstabview: query result contains multiple data values for row \"%s\", column \"%s\"",
-							 rp->name ? rp->name :
-							 (popt.nullPrint ? popt.nullPrint : "(null)"),
-							 cp->name ? cp->name :
-							 (popt.nullPrint ? popt.nullPrint : "(null)"));
+							 displayValue(rp->name, row_ftype, "(null)"),
+							 displayValue(cp->name, col_ftype, "(null)"));
 				goto error;
 			}
 
-			cont.cells[idx] = !PQgetisnull(result, rn, field_for_data) ?
-				PQgetvalue(result, rn, field_for_data) :
-				(popt.nullPrint ? popt.nullPrint : "");
+			if (PQgetisnull(result, rn, field_for_data))
+				value = NULL;
+			else
+				value = PQgetvalue(result, rn, field_for_data);
+			cont.cells[idx] = displayValue(value, data_ftype, "");
 		}
 	}
 
@@ -426,6 +429,30 @@ printCrosstab(const PGresult *result,
 	return retval;
 }
 
+/*
+ * Return the display representation of one cell value in \crosstabview,
+ * following pset substitutions.
+ *
+ * The returned pointer is not to be freed.
+ */
+static char *
+displayValue(char *value, Oid ftype, char *default_null)
+{
+	printQueryOpt popt = pset.popt;
+
+	if (value == NULL)
+		value = popt.nullPrint ? popt.nullPrint : default_null;
+	else if (ftype == BOOLOID)
+	{
+		if (value[0] == 't' && popt.truePrint)
+			value = popt.truePrint;
+		else if (value[0] == 'f' && popt.falsePrint)
+			value = popt.falsePrint;
+	}
+
+	return value;
+}
+
 /*
  * The avl* functions below provide a minimalistic implementation of AVL binary
  * trees, to efficiently collect the distinct values that will form the horizontal

src/test/regress/expected/psql_crosstab.out

@@ -136,6 +136,35 @@ GROUP BY v, h ORDER BY h,v
     |        |    |    | -3 | 
 (3 rows)
 
+\pset null ''
+-- boolean display
+\pset display_true 'Aye'
+\pset display_false 'Nay'
+\pset null 'Wut'
+with rows (display_bools, col_key, val) as (values
+	(false, false, false),
+	(true, true, true),
+	(null, null, null),
+	(null, true, false),
+	(null, false, true),
+	(true, null, false),
+	(false, null, true)
+) select * from rows
+ \crosstabview display_bools col_key val
+ display_bools | Nay | Aye | Wut 
+---------------+-----+-----+-----
+ Nay           | Nay |     | Aye
+ Aye           |     | Aye | Nay
+ Wut           | Aye | Nay | Wut
+(3 rows)
+
+with rows (tst, col, val) as (values
+	(true, null, 42), (true, null, 142857)
+) select * from rows
+ \crosstabview tst col
+\crosstabview: query result contains multiple data values for row "Aye", column "Wut"
+\pset display_true 't'
+\pset display_false 'f'
 \pset null ''
 -- refer to columns by position
 SELECT v,h,string_agg(i::text, E'\n'), string_agg(c, E'\n')

src/test/regress/sql/psql_crosstab.sql

@@ -69,6 +69,30 @@ GROUP BY v, h ORDER BY h,v
  \crosstabview v h i
 \pset null ''
 
+-- boolean display
+\pset display_true 'Aye'
+\pset display_false 'Nay'
+\pset null 'Wut'
+with rows (display_bools, col_key, val) as (values
+	(false, false, false),
+	(true, true, true),
+	(null, null, null),
+	(null, true, false),
+	(null, false, true),
+	(true, null, false),
+	(false, null, true)
+) select * from rows
+ \crosstabview display_bools col_key val
+
+with rows (tst, col, val) as (values
+	(true, null, 42), (true, null, 142857)
+) select * from rows
+ \crosstabview tst col
+
+\pset display_true 't'
+\pset display_false 'f'
+\pset null ''
+
 -- refer to columns by position
 SELECT v,h,string_agg(i::text, E'\n'), string_agg(c, E'\n')
 FROM ctv_data GROUP BY v, h ORDER BY h,v