adjustments_to_test_bitmapset_module.patch

diff --git a/src/test/modules/test_bitmapset/expected/test_bitmapset.out b/src/test/modules/test_bitmapset/expected/test_bitmapset.out
index be7b6399c82..2e204d687df 100644
--- a/src/test/modules/test_bitmapset/expected/test_bitmapset.out
+++ b/src/test/modules/test_bitmapset/expected/test_bitmapset.out
@@ -63,7 +63,7 @@ SELECT test_bms_add_member('(b 10)', 10) AS result;
 SELECT test_bms_add_member('(b)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_replace_members()
@@ -76,7 +76,7 @@ SELECT test_bms_replace_members(NULL, '(b 1 2 3)') AS result;
 SELECT test_bms_replace_members('(b 1 2 3)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_replace_members('(b 1 2 3)', '(b 3 5 6)') AS result;
@@ -108,13 +108,13 @@ SELECT test_bms_replace_members('(b 1 2 3 4 5)', '(b 500 600)') AS result;
 SELECT test_bms_replace_members('(b 1 2 3)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_replace_members('(b 5)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_replace_members(NULL, '(b 5)') AS result;
@@ -126,7 +126,7 @@ SELECT test_bms_replace_members(NULL, '(b 5)') AS result;
 SELECT test_bms_replace_members(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_del_member()
@@ -135,13 +135,13 @@ ERROR:  negative bitmapset member not allowed
 SELECT test_bms_del_member('(b)', 10) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_del_member('(b 10)', 10) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_del_member('(b 10)', 5) AS result;
@@ -193,26 +193,26 @@ SELECT test_bms_del_member('(b 1 50 100 200)', 100) AS result;
 SELECT test_bms_del_member('(b 42)', 42) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_del_member('(b 5)', NULL) AS result;
  result 
 --------
- 
+ (b 5)
 (1 row)
 
 -- bms_del_members()
 SELECT test_bms_del_members('(b)', '(b 10)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_del_members('(b 10)', '(b 10)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_del_members('(b 10)', '(b 5)') AS result;
@@ -262,7 +262,7 @@ SELECT test_bms_del_members('(b 5)', NULL) AS result;
 SELECT test_bms_del_members(NULL, '(b 5)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_join()
@@ -319,7 +319,7 @@ SELECT test_bms_join(NULL, '(b 5)') AS result;
 SELECT test_bms_join(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_union()
@@ -341,7 +341,7 @@ SELECT test_bms_union('(b 1 3 5)', '(b)') AS result;
 SELECT test_bms_union('(b)', '(b)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Overlapping ranges
@@ -383,7 +383,7 @@ SELECT test_bms_union(NULL, '(b 5)') AS result;
 SELECT test_bms_union(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_intersect()
@@ -398,14 +398,14 @@ SELECT test_bms_intersect('(b 1 3 5)', '(b 3 5 7)') AS result;
 SELECT test_bms_intersect('(b 1 3 5)', '(b 2 4 6)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Intersect with empty
 SELECT test_bms_intersect('(b 1 3 5)', '(b)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Intersect with varrying word counts
@@ -425,25 +425,25 @@ SELECT test_bms_intersect('(b 1 2 3 4 5)', '(b 1 300)') AS result;
 SELECT test_bms_intersect('(b 1)', '(b 2)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_intersect('(b 5)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_intersect(NULL, '(b 5)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_intersect(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_int_members()
@@ -458,14 +458,14 @@ SELECT test_bms_int_members('(b 1 3 5)', '(b 3 5 7)') AS result;
 SELECT test_bms_int_members('(b 1 3 5)', '(b 2 4 6)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Intersect with empty
 SELECT test_bms_int_members('(b 1 3 5)', '(b)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Multiple members
@@ -479,25 +479,25 @@ SELECT test_bms_int_members('(b 0 31 32 63 64)', '(b 31 32 64 65)') AS result;
 SELECT test_bms_int_members('(b 1)', '(b 2)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_int_members('(b 5)', NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_int_members(NULL, '(b 5)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_int_members(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_difference()
@@ -519,14 +519,14 @@ SELECT test_bms_difference('(b 1 3 5)', '(b 2 4 6)') AS result;
 SELECT test_bms_difference('(b 1 3 5)', '(b 1 3 5)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Substraction to empty
 SELECT test_bms_difference('(b 42)', '(b 42)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- Subtraction edge case
@@ -556,7 +556,7 @@ SELECT test_bms_difference('(b 1 2 100 200)', '(b 1 2)') AS result;
 SELECT test_bms_difference('(b 5)', '(b 5 10)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_difference('(b 5)', NULL) AS result;
@@ -568,13 +568,13 @@ SELECT test_bms_difference('(b 5)', NULL) AS result;
 SELECT test_bms_difference(NULL, '(b 5)') AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_difference(NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_is_member()
@@ -887,19 +887,19 @@ SELECT length(test_bms_add_range('(b 1 2)', 200, 250)) AS result;
 SELECT test_bms_add_range('(b 5)', 5, NULL) AS result;
  result 
 --------
- 
+ (b 5)
 (1 row)
 
 SELECT test_bms_add_range('(b 5)', NULL, 10) AS result;
  result 
 --------
- 
+ (b 5)
 (1 row)
 
 SELECT test_bms_add_range('(b 5)', NULL, NULL) AS result;
  result 
 --------
- 
+ (b 5)
 (1 row)
 
 SELECT test_bms_add_range(NULL, 5, 10) AS result;
@@ -911,13 +911,13 @@ SELECT test_bms_add_range(NULL, 5, 10) AS result;
 SELECT test_bms_add_range(NULL, 10, 5) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_add_range(NULL, NULL, NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_membership()
@@ -1421,7 +1421,7 @@ SELECT test_bms_subset_compare(NULL, NULL) AS result;
 SELECT test_bms_copy(NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 SELECT test_bms_copy('(b 1 3 5 7)') AS result;
@@ -1434,7 +1434,7 @@ SELECT test_bms_copy('(b 1 3 5 7)') AS result;
 SELECT test_bms_copy(NULL) AS result;
  result 
 --------
- 
+ (b)
 (1 row)
 
 -- bms_add_members()
diff --git a/src/test/modules/test_bitmapset/sql/test_bitmapset.sql b/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
index c6e6bce60a3..c7c3cce93d3 100644
--- a/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
+++ b/src/test/modules/test_bitmapset/sql/test_bitmapset.sql
@@ -258,14 +258,13 @@ SELECT test_bms_singleton_member('(b 42)') AS result;
 SELECT test_bms_singleton_member(NULL) AS result;
 
 -- bms_get_singleton_member()
-SELECT test_bms_get_singleton_member('(b)', 1000);
+SELECT test_bms_get_singleton_member('(b)');
+-- Try with an empty set
+SELECT test_bms_get_singleton_member(NULL) AS result;
 -- Not a singleton, returns input default
-SELECT test_bms_get_singleton_member('(b 3 6)', 1000) AS result;
+SELECT test_bms_get_singleton_member('(b 3 6)') AS result;
 -- Singletone, returns sole member
-SELECT test_bms_get_singleton_member('(b 400)', 1000) AS result;
--- Test module checks
-SELECT test_bms_get_singleton_member('', 1000) AS result;
-SELECT test_bms_get_singleton_member(NULL, -1) AS result;
+SELECT test_bms_get_singleton_member('(b 400)') AS result;
 
 -- bms_next_member() and bms_prev_member()
 -- First member
diff --git a/src/test/modules/test_bitmapset/test_bitmapset--1.0.sql b/src/test/modules/test_bitmapset/test_bitmapset--1.0.sql
index b95c4d0dda5..227ecb5aa3b 100644
--- a/src/test/modules/test_bitmapset/test_bitmapset--1.0.sql
+++ b/src/test/modules/test_bitmapset/test_bitmapset--1.0.sql
@@ -68,7 +68,7 @@ CREATE FUNCTION test_bms_singleton_member(text)
 RETURNS integer STRICT
 AS 'MODULE_PATHNAME' LANGUAGE C;
 
-CREATE FUNCTION test_bms_get_singleton_member(text, integer)
+CREATE FUNCTION test_bms_get_singleton_member(text)
 RETURNS integer
 AS 'MODULE_PATHNAME' LANGUAGE C;
 
diff --git a/src/test/modules/test_bitmapset/test_bitmapset.c b/src/test/modules/test_bitmapset/test_bitmapset.c
index 2e821320836..88fd71d5495 100644
--- a/src/test/modules/test_bitmapset/test_bitmapset.c
+++ b/src/test/modules/test_bitmapset/test_bitmapset.c
@@ -26,7 +26,6 @@
 #include "nodes/pg_list.h"
 #include "utils/builtins.h"
 #include "utils/timestamp.h"
-#include "varatt.h"
 
 PG_MODULE_MAGIC;
 
@@ -84,105 +83,109 @@ PG_FUNCTION_INFO_V1(test_random_operations);
 				 #expr, __FILE__, __LINE__); \
 	} while (0)
 
+static const char *emptyset = "(b)";
+
 /* Encode/Decode to/from TEXT and Bitmapset */
-#define BITMAPSET_TO_TEXT(bms) cstring_to_text(nodeToString(bms))
+#define BITMAPSET_TO_TEXT(bms) cstring_to_text(bms ? nodeToString(bms) : emptyset)
 #define TEXT_TO_BITMAPSET(str) ((Bitmapset *) stringToNode(text_to_cstring(str)))
 
+/* Helper macro to fetch Text parameters as Bitmapsets. SQL-NULL means empty set */
+#define PG_ARG_GETBITMAPSET(n) \
+	(PG_ARGISNULL(n) ? NULL : TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(n)))
+
+/*
+ * Helper macro to handle converting sets back to text, freeing the set and
+ * returning the resulting text representation of the set.  Beware of double
+ * evaluation hazard of 'bms'.
+ */
+#define PG_RETURN_BITMAPSET_AS_TEXT(bms) \
+	do { \
+		text	   *result = BITMAPSET_TO_TEXT(bms); \
+		bms_free(bms); \
+		PG_RETURN_TEXT_P(result); \
+	} while (0);
+
 /*
  * Individual test functions for each bitmapset API function
+ *
+ * Primarily, we aim to keep these as close to simple wrapper functions as
+ * possible in order to publish the functions of bitmapset.c to the SQL layer
+ * with as little interference as possible.  We opt to return SQL NULL in
+ * cases where the input given to the SQL function isn't valid to pass to the
+ * underlying bitmapset.c function.  For example we cannot do much useful
+ * testing if someone calls test_bms_make_singleton(NULL) since
+ * bms_make_singleton() expects an integer argument.
+ *
+ * For function arguments which are to be converted to Bitmapsets, we accept
+ * SQL NULL as a valid argument to mean an empty set.  Optionally callers may
+ * pass '(b)'.
+ *
+ * For the test functions which return a Bitmapset, these are converted back
+ * to Text with empty sets being represented as '(b)'.
  */
 
 Datum
 test_bms_add_member(PG_FUNCTION_ARGS)
 {
+	Bitmapset  *bms;
 	int			member;
-	Bitmapset  *bms = NULL;
-	text	   *result;
 
 	if (PG_ARGISNULL(1))
-		PG_RETURN_NULL();
-
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+		PG_RETURN_NULL();		/* invalid input */
 
+	bms = PG_ARG_GETBITMAPSET(0);
 	member = PG_GETARG_INT32(1);
-	bms = bms_add_member(bms, member);
-	result = BITMAPSET_TO_TEXT(bms);
 
-	if (bms)
-		bms_free(bms);
+	bms = bms_add_member(bms, member);
 
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms);
 }
 
 Datum
 test_bms_add_members(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
-	text	   *result;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
-	/* IMPORTANT: bms_add_members modifies/frees the first argument */
+	/* left input is recycled */
 	bms1 = bms_add_members(bms1, bms2);
+	bms_free(bms2);
 
-	if (bms2)
-		bms_free(bms2);
-
-	result = BITMAPSET_TO_TEXT(bms1);
-	bms_free(bms1);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms1);
 }
 
 Datum
 test_bms_del_member(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		member;
-	text	   *result;
 
 	if (PG_ARGISNULL(1))
-		PG_RETURN_NULL();
-
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+		PG_RETURN_NULL();		/* invalid input */
 
+	bms = PG_ARG_GETBITMAPSET(0);
 	member = PG_GETARG_INT32(1);
-	bms = bms_del_member(bms, member);
-
-	if (bms_is_empty(bms))
-		PG_RETURN_NULL();
 
-	result = BITMAPSET_TO_TEXT(bms);
-	bms_free(bms);
+	bms = bms_del_member(bms, member);
 
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms);
 }
 
 Datum
 test_bms_is_member(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		member;
 	bool		result;
 
 	if (PG_ARGISNULL(1))
-		PG_RETURN_BOOL(false);
-
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+		PG_RETURN_NULL();		/* invalid input */
 
+	bms = PG_ARG_GETBITMAPSET(0);
 	member = PG_GETARG_INT32(1);
-	result = bms_is_member(member, bms);
 
-	if (bms)
-		bms_free(bms);
+	result = bms_is_member(member, bms);
+	bms_free(bms);
 
 	PG_RETURN_BOOL(result);
 }
@@ -190,16 +193,11 @@ test_bms_is_member(PG_FUNCTION_ARGS)
 Datum
 test_bms_num_members(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
-	int			result = 0;
-
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
+	int			result;
 
 	result = bms_num_members(bms);
-
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_INT32(result);
 }
@@ -207,65 +205,40 @@ test_bms_num_members(PG_FUNCTION_ARGS)
 Datum
 test_bms_make_singleton(PG_FUNCTION_ARGS)
 {
-	int32		member;
 	Bitmapset  *bms;
-	text	   *result;
+	int32		member;
 
 	if (PG_ARGISNULL(0))
-		PG_RETURN_NULL();
+		PG_RETURN_NULL();		/* invalid input */
 
 	member = PG_GETARG_INT32(0);
 	bms = bms_make_singleton(member);
 
-	result = BITMAPSET_TO_TEXT(bms);
-	bms_free(bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms);
 }
 
 Datum
 test_bms_copy(PG_FUNCTION_ARGS)
 {
-	text	   *bms_data;
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	Bitmapset  *copy_bms;
-	text	   *result;
 
-	if (PG_ARGISNULL(0))
-		PG_RETURN_NULL();
-
-	bms_data = PG_GETARG_TEXT_PP(0);
-	bms = TEXT_TO_BITMAPSET(bms_data);
 	copy_bms = bms_copy(bms);
-	result = BITMAPSET_TO_TEXT(copy_bms);
-
-	if (bms)
-		bms_free(bms);
-	if (copy_bms)
-		bms_free(copy_bms);
+	bms_free(bms);
 
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(copy_bms);
 }
 
 Datum
 test_bms_equal(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	bool		result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_equal(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_BOOL(result);
 }
@@ -273,47 +246,25 @@ test_bms_equal(PG_FUNCTION_ARGS)
 Datum
 test_bms_union(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	Bitmapset  *result_bms;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
 
 	result_bms = bms_union(bms1, bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
-
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(result_bms);
 }
 
 Datum
 test_bms_membership(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	BMS_Membership result;
 
-	if (PG_ARGISNULL(0))
-		PG_RETURN_INT32(BMS_EMPTY_SET);
-
-	bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
 	result = bms_membership(bms);
-
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_INT32((int32) result);
 }
@@ -321,19 +272,18 @@ test_bms_membership(PG_FUNCTION_ARGS)
 Datum
 test_bms_next_member(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		prevmember;
 	int			result;
 
-	if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
-		PG_RETURN_INT32(-2);
+	if (PG_ARGISNULL(1))
+		PG_RETURN_NULL();		/* invalid input */
 
-	bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+	bms = PG_ARG_GETBITMAPSET(0);
 	prevmember = PG_GETARG_INT32(1);
-	result = bms_next_member(bms, prevmember);
 
-	if (bms)
-		bms_free(bms);
+	result = bms_next_member(bms, prevmember);
+	bms_free(bms);
 
 	PG_RETURN_INT32(result);
 }
@@ -341,82 +291,41 @@ test_bms_next_member(PG_FUNCTION_ARGS)
 Datum
 test_bms_intersect(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	Bitmapset  *result_bms;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
 
 	result_bms = bms_intersect(bms1, bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
-
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(result_bms);
 }
 
 Datum
 test_bms_difference(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	Bitmapset  *result_bms;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
 
 	result_bms = bms_difference(bms1, bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
-
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(result_bms);
 }
 
 Datum
 test_bms_compare(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	int			result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_compare(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_INT32(result);
 }
@@ -424,16 +333,11 @@ test_bms_compare(PG_FUNCTION_ARGS)
 Datum
 test_bms_is_empty(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	bool		result;
 
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
 	result = bms_is_empty(bms);
-
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_BOOL(result);
 }
@@ -441,22 +345,13 @@ test_bms_is_empty(PG_FUNCTION_ARGS)
 Datum
 test_bms_is_subset(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	bool		result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_is_subset(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_BOOL(result);
 }
@@ -464,22 +359,13 @@ test_bms_is_subset(PG_FUNCTION_ARGS)
 Datum
 test_bms_subset_compare(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	BMS_Comparison result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_subset_compare(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_INT32((int32) result);
 }
@@ -487,16 +373,11 @@ test_bms_subset_compare(PG_FUNCTION_ARGS)
 Datum
 test_bms_singleton_member(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	int			result;
 
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
 	result = bms_singleton_member(bms);
-
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_INT32(result);
 }
@@ -504,47 +385,34 @@ test_bms_singleton_member(PG_FUNCTION_ARGS)
 Datum
 test_bms_get_singleton_member(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
-	int32		default_member = PG_GETARG_INT32(1);
-	bool		success;
-	int			member = -1;
-
-	if (PG_ARGISNULL(0))
-		PG_RETURN_INT32(default_member);
-
-	bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
+	int			member;
 
 	/*
-	 * bms_get_singleton_member returns bool and stores result in member
-	 * pointer
+	 * Keep this simple.  Return -1 when we detect the set isn't a singleton
+	 * set, otherwise return the singleton member.
 	 */
-	success = bms_get_singleton_member(bms, &member);
-	bms_free(bms);
+	if (!bms_get_singleton_member(bms, &member))
+		member = -1;
 
-	if (success)
-		PG_RETURN_INT32(member);
+	bms_free(bms);
 
-	PG_RETURN_INT32(default_member);
+	PG_RETURN_INT32(member);
 }
 
 Datum
 test_bms_prev_member(PG_FUNCTION_ARGS)
 {
-	text	   *bms_data;
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		prevmember;
 	int			result;
 
-	if (PG_ARGISNULL(0))
-		PG_RETURN_INT32(-2);
+	if (PG_ARGISNULL(1))
+		PG_RETURN_NULL();		/* invalid input */
 
-	bms_data = PG_GETARG_TEXT_PP(0);
+	bms = PG_ARG_GETBITMAPSET(0);
 	prevmember = PG_GETARG_INT32(1);
 
-	if (VARSIZE_ANY_EXHDR(bms_data) == 0)
-		PG_RETURN_INT32(-2);
-
-	bms = TEXT_TO_BITMAPSET(bms_data);
 	result = bms_prev_member(bms, prevmember);
 	bms_free(bms);
 
@@ -554,22 +422,13 @@ test_bms_prev_member(PG_FUNCTION_ARGS)
 Datum
 test_bms_overlap(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	bool		result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_overlap(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_BOOL(result);
 }
@@ -577,52 +436,47 @@ test_bms_overlap(PG_FUNCTION_ARGS)
 Datum
 test_bms_overlap_list(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	ArrayType  *array;
 	List	   *int_list = NIL;
 	bool		result;
-	Datum	   *elem_datums;
-	bool	   *elem_nulls;
+	Datum	   *elem_datums = NULL;
+	bool	   *elem_nulls = NULL;
 	int			elem_count;
 	int			i;
 
-	if (PG_ARGISNULL(0))
-		PG_RETURN_BOOL(false);
+	bms = PG_ARG_GETBITMAPSET(0);
 
-	bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (PG_ARGISNULL(1))
+	if (!PG_ARGISNULL(1))
 	{
-		if (bms)
-			bms_free(bms);
-		PG_RETURN_BOOL(false);
-	}
-
-	array = PG_GETARG_ARRAYTYPE_P(1);
+		array = PG_GETARG_ARRAYTYPE_P(1);
 
-	deconstruct_array(array,
-					  INT4OID, sizeof(int32), true, 'i',
-					  &elem_datums, &elem_nulls, &elem_count);
+		deconstruct_array(array,
+						  INT4OID, sizeof(int32), true, 'i',
+						  &elem_datums, &elem_nulls, &elem_count);
 
-	for (i = 0; i < elem_count; i++)
-	{
-		if (!elem_nulls[i])
+		for (i = 0; i < elem_count; i++)
 		{
-			int32		member = DatumGetInt32(elem_datums[i]);
+			if (!elem_nulls[i])
+			{
+				int32		member = DatumGetInt32(elem_datums[i]);
 
-			int_list = lappend_int(int_list, member);
+				int_list = lappend_int(int_list, member);
+			}
 		}
 	}
 
 	result = bms_overlap_list(bms, int_list);
 
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	list_free(int_list);
 
-	pfree(elem_datums);
-	pfree(elem_nulls);
+	if (elem_datums)
+		pfree(elem_datums);
+
+	if (elem_nulls)
+		pfree(elem_nulls);
 
 	PG_RETURN_BOOL(result);
 }
@@ -630,22 +484,13 @@ test_bms_overlap_list(PG_FUNCTION_ARGS)
 Datum
 test_bms_nonempty_difference(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	bool		result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
 	result = bms_nonempty_difference(bms1, bms2);
-
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_BOOL(result);
 }
@@ -653,22 +498,16 @@ test_bms_nonempty_difference(PG_FUNCTION_ARGS)
 Datum
 test_bms_member_index(PG_FUNCTION_ARGS)
 {
-	text	   *bms_data;
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		member;
 	int			result;
 
-	if (PG_ARGISNULL(0))
-		PG_RETURN_INT32(-1);
+	if (PG_ARGISNULL(1))
+		PG_RETURN_NULL();		/* invalid input */
 
-	bms_data = PG_GETARG_TEXT_PP(0);
+	bms = PG_ARG_GETBITMAPSET(0);
 	member = PG_GETARG_INT32(1);
 
-	if (VARSIZE_ANY_EXHDR(bms_data) == 0)
-		PG_RETURN_INT32(-1);
-
-	bms = TEXT_TO_BITMAPSET(bms_data);
-
 	result = bms_member_index(bms, member);
 	bms_free(bms);
 
@@ -678,169 +517,85 @@ test_bms_member_index(PG_FUNCTION_ARGS)
 Datum
 test_bms_add_range(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms;
 	int32		lower,
 				upper;
-	text	   *result;
 
 	if (PG_ARGISNULL(1) || PG_ARGISNULL(2))
-		PG_RETURN_NULL();
-
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
+		PG_RETURN_NULL();		/* invalid input */
 
+	bms = PG_ARG_GETBITMAPSET(0);
 	lower = PG_GETARG_INT32(1);
 	upper = PG_GETARG_INT32(2);
 
-	/* Check for invalid range */
-	if (upper < lower)
-	{
-		if (bms)
-			bms_free(bms);
-		PG_RETURN_NULL();
-	}
-
 	bms = bms_add_range(bms, lower, upper);
 
-	result = BITMAPSET_TO_TEXT(bms);
-	if (bms)
-		bms_free(bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms);
 }
 
 Datum
 test_bms_int_members(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 
+	/* left input gets recycled */
 	bms1 = bms_int_members(bms1, bms2);
 
-	if (bms2)
-		bms_free(bms2);
-
-	if (bms1 == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(bms1);
-
-	if (bms1)
-		bms_free(bms1);
+	bms_free(bms2);
 
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms1);
 }
 
 Datum
 test_bms_del_members(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
-	Bitmapset  *result_bms;
-	text	   *result;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
-	/* IMPORTANT: bms_del_members modifies/frees the first argument */
-	result_bms = bms_del_members(bms1, bms2);
-
-	/* bms1 is now invalid, do not free it */
-
-	if (bms2)
-		bms_free(bms2);
-
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
+	/* left input gets recycled */
+	bms1 = bms_del_members(bms1, bms2);
+	bms_free(bms2);
 
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms1);
 }
 
 Datum
 test_bms_replace_members(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
-	Bitmapset  *result_bms;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
-	/* IMPORTANT: bms_replace_members modifies/frees the first argument */
-	result_bms = bms_replace_members(bms1, bms2);
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 
-	/* bms1 is now invalid, do not free it */
+	/* left input gets recycled */
+	bms1 = bms_replace_members(bms1, bms2);
 
-	if (bms2)
-		bms_free(bms2);
-
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
-
-	PG_RETURN_TEXT_P(result);
+	bms_free(bms2);
+	PG_RETURN_BITMAPSET_AS_TEXT(bms1);
 }
 
 Datum
 test_bms_join(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	Bitmapset  *result_bms;
-	text	   *result;
-
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
 
-	/* IMPORTANT: bms_join may recycle either input arguments */
+	/* either input can be recycled */
 	result_bms = bms_join(bms1, bms2);
 
-	/* bms1 and bms2 may have been recycled! Do not free any of them. */
+	/* memory cleanup seems more tricky than it's worth here */
 
-	if (result_bms == NULL)
-		PG_RETURN_NULL();
-
-	result = BITMAPSET_TO_TEXT(result_bms);
-	bms_free(result_bms);
-
-	PG_RETURN_TEXT_P(result);
+	PG_RETURN_BITMAPSET_AS_TEXT(result_bms);
 }
 
 Datum
 test_bms_hash_value(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	uint32		hash_result;
 
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
 	hash_result = bms_hash_value(bms);
-
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_INT32(hash_result);
 }
@@ -848,21 +603,12 @@ test_bms_hash_value(PG_FUNCTION_ARGS)
 Datum
 test_bitmap_hash(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms = NULL;
-	Bitmapset  *bms_ptr;
+	Bitmapset  *bms = PG_ARG_GETBITMAPSET(0);
 	uint32		hash_result;
 
-	if (!PG_ARGISNULL(0))
-		bms = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	bms_ptr = bms;
-
 	/* Call bitmap_hash */
-	hash_result = bitmap_hash(&bms_ptr, sizeof(Bitmapset *));
-
-	/* Clean up */
-	if (!PG_ARGISNULL(0) && bms_ptr)
-		bms_free(bms_ptr);
+	hash_result = bitmap_hash(&bms, sizeof(Bitmapset *));
+	bms_free(bms);
 
 	PG_RETURN_INT32(hash_result);
 }
@@ -870,30 +616,14 @@ test_bitmap_hash(PG_FUNCTION_ARGS)
 Datum
 test_bitmap_match(PG_FUNCTION_ARGS)
 {
-	Bitmapset  *bms1 = NULL,
-			   *bms2 = NULL;
-	Bitmapset  *bms_ptr1,
-			   *bms_ptr2;
+	Bitmapset  *bms1 = PG_ARG_GETBITMAPSET(0);
+	Bitmapset  *bms2 = PG_ARG_GETBITMAPSET(1);
 	int			match_result;
 
-	if (!PG_ARGISNULL(0))
-		bms1 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(0));
-
-	if (!PG_ARGISNULL(1))
-		bms2 = TEXT_TO_BITMAPSET(PG_GETARG_TEXT_PP(1));
-
-	/* Set up pointers to the Bitmapsets */
-	bms_ptr1 = bms1;
-	bms_ptr2 = bms2;
-
 	/* Call bitmap_match with addresses of the Bitmapset pointers */
-	match_result = bitmap_match(&bms_ptr1, &bms_ptr2, sizeof(Bitmapset *));
-
-	/* Clean up */
-	if (bms1)
-		bms_free(bms1);
-	if (bms2)
-		bms_free(bms2);
+	match_result = bitmap_match(&bms1, &bms2, sizeof(Bitmapset *));
+	bms_free(bms1);
+	bms_free(bms2);
 
 	PG_RETURN_INT32(match_result);
 }
@@ -1031,8 +761,7 @@ test_random_operations(PG_FUNCTION_ARGS)
 		total_ops++;
 	}
 
-	if (bms)
-		bms_free(bms);
+	bms_free(bms);
 
 	PG_RETURN_INT32(total_ops);
 }