Add a non-strict version of jsonb_set

jsonb_set_lax() is the same as jsonb_set, except that it takes and extra
argument that specifies what to do if the value argument is NULL. The
default is 'use_json_null'. Other possibilities are 'raise_exception',
'return_target' and 'delete_key', all these behaviours having been
suggested as reasonable by various users.

Discussion: https://postgr.es/m/375873e2-c957-3a8d-64f9-26c43c2b16e7@2ndQuadrant.com

Reviewed by: Pavel Stehule

1 files changed, 64 insertions, 0 deletions

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index ab5a24a8584..4b5a0214dca 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -4396,6 +4396,70 @@ jsonb_set(PG_FUNCTION_ARGS)
 
 
 /*
+ * SQL function jsonb_set_lax(jsonb, text[], jsonb, boolean, text)
+ */
+Datum
+jsonb_set_lax(PG_FUNCTION_ARGS)
+{
+	/* Jsonb	   *in = PG_GETARG_JSONB_P(0); */
+	/* ArrayType  *path = PG_GETARG_ARRAYTYPE_P(1); */
+	/* Jsonb	  *newval = PG_GETARG_JSONB_P(2); */
+	/* bool		create = PG_GETARG_BOOL(3); */
+	text       *handle_null;
+	char       *handle_val;
+
+	if (PG_ARGISNULL(0) || PG_ARGISNULL(1) || PG_ARGISNULL(3))
+		PG_RETURN_NULL();
+
+	/* could happen if they pass in an explicit NULL */
+	if (PG_ARGISNULL(4))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("need delete_key, return_target, use_json_null, or raise_exception")));
+
+	/* if the new value isn't an SQL NULL just call jsonb_set */
+	if (! PG_ARGISNULL(2))
+		return jsonb_set(fcinfo);
+
+	handle_null = PG_GETARG_TEXT_P(4);
+	handle_val = text_to_cstring(handle_null);
+
+	if (strcmp(handle_val,"raise_exception") == 0)
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
+				 errmsg("NULL is not allowed"),
+				 errdetail("exception raised due to \"null_value_treatment => 'raise_exception'\""),
+				 errhint("to avoid, either change the null_value_treatment argument or ensure that an SQL NULL is not used")));
+	}
+	else if (strcmp(handle_val, "use_json_null") == 0)
+	{
+		Datum	  newval;
+
+		newval = DirectFunctionCall1(jsonb_in, CStringGetDatum("null"));
+
+		fcinfo->args[2].value = newval;
+		fcinfo->args[2].isnull = false;
+		return jsonb_set(fcinfo);
+	}
+	else if (strcmp(handle_val, "delete_key") == 0)
+	{
+		return jsonb_delete_path(fcinfo);
+	}
+	else if (strcmp(handle_val, "return_target") == 0)
+	{
+		Jsonb	   *in = PG_GETARG_JSONB_P(0);
+		PG_RETURN_JSONB_P(in);
+	}
+	else
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("need delete_key, return_target, use_json_null, or raise_exception")));
+	}
+}
+
+/*
  * SQL function jsonb_delete_path(jsonb, text[])
  */
 Datum