Extract 'EXISTS(left) && EXISTS(right)' from jsonpath 'left OP right'

# Conflicts:
#	sql/jsquery.sql

Author: Nikita Glukhov

expected/jsquery.out

@@ -2823,6 +2823,24 @@ select gin_debug_jsonpath_value_path('$.a > 1');
 
 (1 row)
 
+SELECT gin_debug_jsonpath_value_path('lax $.a == $.b');
+ gin_debug_jsonpath_value_path 
+-------------------------------
+ AND                          +
+   a = * , entry 0            +
+   b = * , entry 1            +
+ 
+(1 row)
+
+SELECT gin_debug_jsonpath_value_path('strict $.a == $.b');
+ gin_debug_jsonpath_value_path 
+-------------------------------
+ AND                          +
+   a = * , entry 0            +
+   b = * , entry 1            +
+ 
+(1 row)
+
 SELECT gin_debug_jsonpath_path_value('lax    $');
  gin_debug_jsonpath_path_value 
 -------------------------------
@@ -3954,6 +3972,32 @@ SELECT gin_debug_jsonpath_path_value('strict $.a > 1 && $.a < 2 && $.b >= 3 && $
 
 (1 row)
 
+SELECT gin_debug_jsonpath_path_value('lax $.a == $.b');
+ gin_debug_jsonpath_path_value 
+-------------------------------
+ AND                          +
+   OR                         +
+     #.a = * , entry 0        +
+     #.a.# = * , entry 1      +
+     a = * , entry 2          +
+     a.# = * , entry 3        +
+   OR                         +
+     #.b = * , entry 4        +
+     #.b.# = * , entry 5      +
+     b = * , entry 6          +
+     b.# = * , entry 7        +
+ 
+(1 row)
+
+SELECT gin_debug_jsonpath_path_value('strict $.a == $.b');
+ gin_debug_jsonpath_path_value 
+-------------------------------
+ AND                          +
+   a = * , entry 0            +
+   b = * , entry 1            +
+ 
+(1 row)
+
 SELECT gin_debug_jsonpath_laxpath_value('lax    $');
  gin_debug_jsonpath_laxpath_value 
 ----------------------------------
@@ -4232,6 +4276,24 @@ SELECT gin_debug_jsonpath_laxpath_value('strict $.a > 1 && $.a < 2 && $.b >= 3 &
 
 (1 row)
 
+SELECT gin_debug_jsonpath_laxpath_value('lax $.a == $.b');
+ gin_debug_jsonpath_laxpath_value 
+----------------------------------
+ AND                             +
+   a = * , entry 0               +
+   b = * , entry 1               +
+ 
+(1 row)
+
+SELECT gin_debug_jsonpath_laxpath_value('strict $.a == $.b');
+ gin_debug_jsonpath_laxpath_value 
+----------------------------------
+ AND                             +
+   a = * , entry 0               +
+   b = * , entry 1               +
+ 
+(1 row)
+
 ---table and index
 select count(*) from test_jsquery where (v->>'review_helpful_votes')::int4 > 0;
  count 

jsquery_extract.c

@@ -551,13 +551,14 @@ appendJsonPathExprNode(ExtractedNode *result, ExtractedNode *node, PathItem *pat
 }
 
 static ExtractedNode *
-extractJsonPathExists(JsonPathItem *jpi, int flags, bool indirect, PathItem *path)
+extractJsonPathExists(JsonPathItem *jpi, int flags, bool indirect, bool unwrap,
+					  PathItem *path)
 {
 	List	   *paths;
 	ListCell   *lc;
 	ExtractedNode *result;
 
-	if (!(paths = extractJsonPath(jpi, flags, false, path)))
+	if (!(paths = extractJsonPath(jpi, flags, unwrap, path)))
 		return NULL;
 
 	result = NULL;
@@ -668,7 +669,20 @@ extractJsonPathExpr(JsonPathItem *jpi, int flags, bool not, bool indirect,
 					greater = !greater;
 				}
 				else
-					return NULL;
+				{
+					ExtractedNode *lnode;
+					ExtractedNode *rnode;
+
+					lnode = extractJsonPathExists(&larg, flags, indirect, true, path);
+					rnode = extractJsonPathExists(&rarg, flags, indirect, true, path);
+
+					if (lnode && rnode)
+						return makeBinaryNode(eAnd, path, indirect, lnode, rnode);
+					else if (lnode)
+						return lnode;
+					else
+						return rnode;
+				}
 
 				if (!(paths = extractJsonPath(patharg, flags, true, path)))
 					return NULL;
@@ -755,7 +769,7 @@ extractJsonPathExpr(JsonPathItem *jpi, int flags, bool not, bool indirect,
 
 				jspGetArg(jpi, &elem);
 
-				return extractJsonPathExists(&elem, flags, indirect, path);
+				return extractJsonPathExists(&elem, flags, indirect, false, path);
 			}
 
 		default:
@@ -1374,7 +1388,7 @@ extractJsonPathQuery(JsonPath *jp, bool exists, bool arrayPathItems, int optimiz
 
 	jspInit(&jsp, jp);
 	root = exists
-		? extractJsonPathExists(&jsp, flags, false, NULL)
+		? extractJsonPathExists(&jsp, flags, false, false, NULL)
 		: extractJsonPathExpr(&jsp, flags, false, false, NULL);
 
 	return emitExtractedQuery(root, optimize, makeHandler, checkHandler, extra);

sql/jsquery.sql

@@ -510,6 +510,9 @@ select gin_debug_jsonpath_value_path('strict exists($.a.b ? (@.c.d == 1))');
 
 select gin_debug_jsonpath_value_path('$.a > 1');
 
+SELECT gin_debug_jsonpath_value_path('lax $.a == $.b');
+SELECT gin_debug_jsonpath_value_path('strict $.a == $.b');
+
 SELECT gin_debug_jsonpath_path_value('lax    $');
 SELECT gin_debug_jsonpath_path_value('strict $');
 SELECT gin_debug_jsonpath_path_value('lax    $.a');
@@ -553,6 +556,9 @@ select gin_debug_jsonpath_path_value('lax    $.a[*].b[*] == 1');
 SELECT gin_debug_jsonpath_path_value('lax    $.a > 1 && $.a < 2 && $.b >= 3 && $.c <= "aaa"');
 SELECT gin_debug_jsonpath_path_value('strict $.a > 1 && $.a < 2 && $.b >= 3 && $.c <= "aaa"');
 
+SELECT gin_debug_jsonpath_path_value('lax $.a == $.b');
+SELECT gin_debug_jsonpath_path_value('strict $.a == $.b');
+
 SELECT gin_debug_jsonpath_laxpath_value('lax    $');
 SELECT gin_debug_jsonpath_laxpath_value('strict $');
 SELECT gin_debug_jsonpath_laxpath_value('lax    $.a');
@@ -595,6 +601,9 @@ select gin_debug_jsonpath_laxpath_value('lax    $.a[*].b[*] == 1');
 SELECT gin_debug_jsonpath_laxpath_value('lax    $.a > 1 && $.a < 2 && $.b >= 3 && $.c <= "aaa"');
 SELECT gin_debug_jsonpath_laxpath_value('strict $.a > 1 && $.a < 2 && $.b >= 3 && $.c <= "aaa"');
 
+SELECT gin_debug_jsonpath_laxpath_value('lax $.a == $.b');
+SELECT gin_debug_jsonpath_laxpath_value('strict $.a == $.b');
+
 ---table and index
 
 select count(*) from test_jsquery where (v->>'review_helpful_votes')::int4 > 0;