Add jsonpath IS UNKNOWN predicate

Author: Nikita Glukhov

src/backend/utils/adt/jsonpath.c

@@ -288,6 +288,12 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey, bool printBracket
 			printJsonPathItem(buf, &elem, false, false);
 			appendStringInfoChar(buf, ')');
 			break;
+		case jpiIsUnknown:
+			appendStringInfoChar(buf, '(');
+			jspGetArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendBinaryStringInfo(buf, ") is unknown", 12);
+			break;
 		case jpiCurrent:
 			Assert(!inKey);
 			appendStringInfoChar(buf, '@');

src/backend/utils/adt/jsonpath_exec.c

@@ -488,6 +488,18 @@ recursiveExecute(JsonPathItem *jsp, List *vars, JsonbValue *jb, List **found)
 					break;
 			}
 			break;
+		case jpiIsUnknown:
+			jspGetArg(jsp, &elem);
+			switch ((res = recursiveExecute(&elem, vars, jb, NULL)))
+			{
+				case jperError:
+					res = jperOk;
+					break;
+				default:
+					res = jperNotFound;
+					break;
+			}
+			break;
 		case jpiKey:
 			if (JsonbType(jb) == jbvObject)
 			{

src/backend/utils/adt/jsonpath_gram.y

@@ -207,7 +207,7 @@ makeAny(int first, int last)
 	int					optype;
 }
 
-%token	<str>		TO_P NULL_P TRUE_P FALSE_P
+%token	<str>		TO_P NULL_P TRUE_P FALSE_P IS_P UNKNOWN_P
 %token	<str>		STRING_P NUMERIC_P INT_P VARIABLE_P
 %token	<str>		OR_P AND_P NOT_P
 %token	<str>		LESS_P LESSEQUAL_P EQUAL_P NOTEQUAL_P GREATEREQUAL_P GREATER_P
@@ -241,6 +241,8 @@ result:
 scalar_value:
 	STRING_P						{ $$ = makeItemString(&$1); }
 	| TO_P							{ $$ = makeItemString(&$1); }
+	| IS_P							{ $$ = makeItemString(&$1); }
+	| UNKNOWN_P						{ $$ = makeItemString(&$1); }
 	| NULL_P						{ $$ = makeItemString(NULL); }
 	| TRUE_P						{ $$ = makeItemBool(true); }
 	| FALSE_P						{ $$ = makeItemBool(false); }
@@ -283,7 +285,7 @@ predicate:
 //	| expr STARTS WITH '$' STRING_P	{ $$ = ...; }
 //	| expr STARTS WITH '$' STRING_P	{ $$ = ...; }
 //	| '.' any_key right_expr		{ $$ = makeItemList(list_make2($2, $3)); }
-//	| '(' predicate ')' IS UNKNOWN	{ $$ = makeItemUnary(jpiIsUnknown, $2); }
+	| '(' predicate ')' IS_P UNKNOWN_P	{ $$ = makeItemUnary(jpiIsUnknown, $2); }
 	| predicate AND_P predicate		{ $$ = makeItemBinary(jpiAnd, $1, $3); }
 	| predicate OR_P predicate		{ $$ = makeItemBinary(jpiOr, $1, $3); }
 	| NOT_P delimited_predicate 	{ $$ = makeItemUnary(jpiNot, $2); }

src/backend/utils/adt/jsonpath_scan.l

@@ -270,10 +270,12 @@ typedef struct keyword
  */
 
 static keyword keywords[] = {
+	{ 2, true,	IS_P,		"is"},
 	{ 2, false,	TO_P,		"to"},
 	{ 4, true,	NULL_P,		"null"},
 	{ 4, true,	TRUE_P,		"true"},
-	{ 5, true,	FALSE_P,	"false"}
+	{ 5, true,	FALSE_P,	"false"},
+	{ 7, true,	UNKNOWN_P,	"unknown"},
 };
 
 static int

src/test/regress/expected/jsonb_jsonpath.out

@@ -106,6 +106,18 @@ select _jsonpath_exists(jsonb '{"a": [1,2,3], "b": [3,4,null]}', '$ ? (@.a[*] >=
  t
 (1 row)
 
+select _jsonpath_exists(jsonb '1', '$ ? ((@ == "1") is unknown)');
+ _jsonpath_exists 
+------------------
+ t
+(1 row)
+
+select _jsonpath_exists(jsonb '1', '$ ? ((@ == 1) is unknown)');
+ _jsonpath_exists 
+------------------
+ f
+(1 row)
+
 select * from _jsonpath_query(jsonb '{"a": 12, "b": {"a": 13}}', '$.a');
  _jsonpath_query 
 -----------------

src/test/regress/expected/jsonpath.out

@@ -225,6 +225,12 @@ select '$.g ? (.x >= @[*]?(@.a > "abc"))'::jsonpath;
  $."g"?(@."x" >= @[*]?(@."a" > "abc"))
 (1 row)
 
+select '$.g ? ((x >= 123 || a == 4) is unknown)'::jsonpath;
+                  jsonpath                   
+---------------------------------------------
+ $."g"?(("x" >= 123 || "a" == 4) is unknown)
+(1 row)
+
 select '$.g ? (zip == $zip)'::jsonpath;
         jsonpath         
 -------------------------

src/test/regress/sql/jsonb_jsonpath.sql

@@ -17,6 +17,8 @@ select _jsonpath_exists(jsonb '{"a": [1,2,3], "b": [3,4,5]}', '$ ? (@.a[*] >  @.
 select _jsonpath_exists(jsonb '{"a": [1,2,3], "b": [3,4,5]}', '$ ? (@.a[*] >= @.b[*])');
 select _jsonpath_exists(jsonb '{"a": [1,2,3], "b": [3,4,"5"]}', '$ ? (@.a[*] >= @.b[*])');
 select _jsonpath_exists(jsonb '{"a": [1,2,3], "b": [3,4,null]}', '$ ? (@.a[*] >= @.b[*])');
+select _jsonpath_exists(jsonb '1', '$ ? ((@ == "1") is unknown)');
+select _jsonpath_exists(jsonb '1', '$ ? ((@ == 1) is unknown)');
 
 select * from _jsonpath_query(jsonb '{"a": 12, "b": {"a": 13}}', '$.a');
 select * from _jsonpath_query(jsonb '{"a": 12, "b": {"a": 13}}', '$.b');

src/test/regress/sql/jsonpath.sql

@@ -39,6 +39,7 @@ select '$.g ? (@.a == 1 || a == 4 && b == 7)'::jsonpath;
 select '$.g ? (@.a == 1 || !(a == 4) && b == 7)'::jsonpath;
 select '$.g ? (@.a == 1 || !(x >= 123 || a == 4) && b == 7)'::jsonpath;
 select '$.g ? (.x >= @[*]?(@.a > "abc"))'::jsonpath;
+select '$.g ? ((x >= 123 || a == 4) is unknown)'::jsonpath;
 
 select '$.g ? (zip == $zip)'::jsonpath;
 select '$.a.[1,2, 3 to 16]'::jsonpath;