Fix handling of nested JSON objects in json_populate_recordset and friends.

populate_recordset_object_start() improperly created a new hash table
(overwriting the link to the existing one) if called at nest levels
greater than one.  This resulted in previous fields not appearing in
the final output, as reported by Matti Hameister in bug #10728.
In 9.4 the problem also affects json_to_recordset.

This perhaps missed detection earlier because the default behavior is to
throw an error for nested objects: you have to pass use_json_as_text = true
to see the problem.

In addition, fix query-lifespan leakage of the hashtable created by
json_populate_record().  This is pretty much the same problem recently
fixed in dblink: creating an intended-to-be-temporary context underneath
the executor's per-tuple context isn't enough to make it go away at the
end of the tuple cycle, because MemoryContextReset is not
MemoryContextResetAndDeleteChildren.

Michael Paquier and Tom Lane

3 files changed, 36 insertions, 0 deletions

diff --git a/src/test/regress/expected/json.out b/src/test/regress/expected/json.out
index 8b8556b2e04..d1e32a19a52 100644
--- a/src/test/regress/expected/json.out
+++ b/src/test/regress/expected/json.out
@@ -1007,6 +1007,13 @@ select * from json_populate_recordset(row('def',99,null)::jpop,'[{"a":[100,200,3
 
 select * from json_populate_recordset(row('def',99,null)::jpop,'[{"c":[100,200,300],"x":43.2},{"a":{"z":true},"b":3,"c":"2012-01-20 10:42:53"}]',true) q;
 ERROR:  invalid input syntax for type timestamp: "[100,200,300]"
+create type jpop2 as (a int, b json, c int, d int);
+select * from json_populate_recordset(null::jpop2, '[{"a":2,"c":3,"b":{"z":4},"d":6}]',true) q;
+ a |    b    | c | d 
+---+---------+---+---
+ 2 | {"z":4} | 3 | 6
+(1 row)
+
 -- using the default use_json_as_text argument
 select * from json_populate_recordset(null::jpop,'[{"a":"blurfl","x":43.2},{"b":3,"c":"2012-01-20 10:42:53"}]') q;
    a    | b |            c             
@@ -1223,3 +1230,11 @@ select * from json_to_recordset('[{"a":1,"b":"foo","d":false},{"a":2,"b":"bar","
  2 | bar | t
 (2 rows)
 
+select * from json_to_recordset('[{"a":1,"b":{"d":"foo"},"c":true},{"a":2,"c":false,"b":{"d":"bar"}}]', true)
+    as x(a int, b json, c boolean);
+ a |      b      | c 
+---+-------------+---
+ 1 | {"d":"foo"} | t
+ 2 | {"d":"bar"} | f
+(2 rows)
+
diff --git a/src/test/regress/expected/json_1.out b/src/test/regress/expected/json_1.out
index b32c3ed09f3..93cb693b2fb 100644
--- a/src/test/regress/expected/json_1.out
+++ b/src/test/regress/expected/json_1.out
@@ -1007,6 +1007,13 @@ select * from json_populate_recordset(row('def',99,null)::jpop,'[{"a":[100,200,3
 
 select * from json_populate_recordset(row('def',99,null)::jpop,'[{"c":[100,200,300],"x":43.2},{"a":{"z":true},"b":3,"c":"2012-01-20 10:42:53"}]',true) q;
 ERROR:  invalid input syntax for type timestamp: "[100,200,300]"
+create type jpop2 as (a int, b json, c int, d int);
+select * from json_populate_recordset(null::jpop2, '[{"a":2,"c":3,"b":{"z":4},"d":6}]',true) q;
+ a |    b    | c | d 
+---+---------+---+---
+ 2 | {"z":4} | 3 | 6
+(1 row)
+
 -- using the default use_json_as_text argument
 select * from json_populate_recordset(null::jpop,'[{"a":"blurfl","x":43.2},{"b":3,"c":"2012-01-20 10:42:53"}]') q;
    a    | b |            c             
@@ -1219,3 +1226,11 @@ select * from json_to_recordset('[{"a":1,"b":"foo","d":false},{"a":2,"b":"bar","
  2 | bar | t
 (2 rows)
 
+select * from json_to_recordset('[{"a":1,"b":{"d":"foo"},"c":true},{"a":2,"c":false,"b":{"d":"bar"}}]', true)
+    as x(a int, b json, c boolean);
+ a |      b      | c 
+---+-------------+---
+ 1 | {"d":"foo"} | t
+ 2 | {"d":"bar"} | f
+(2 rows)
+
diff --git a/src/test/regress/sql/json.sql b/src/test/regress/sql/json.sql
index 3d5ed50126e..bc8bb629781 100644
--- a/src/test/regress/sql/json.sql
+++ b/src/test/regress/sql/json.sql
@@ -325,6 +325,9 @@ select * from json_populate_recordset(row('def',99,null)::jpop,'[{"a":"blurfl","
 select * from json_populate_recordset(row('def',99,null)::jpop,'[{"a":[100,200,300],"x":43.2},{"a":{"z":true},"b":3,"c":"2012-01-20 10:42:53"}]',true) q;
 select * from json_populate_recordset(row('def',99,null)::jpop,'[{"c":[100,200,300],"x":43.2},{"a":{"z":true},"b":3,"c":"2012-01-20 10:42:53"}]',true) q;
 
+create type jpop2 as (a int, b json, c int, d int);
+select * from json_populate_recordset(null::jpop2, '[{"a":2,"c":3,"b":{"z":4},"d":6}]',true) q;
+
 -- using the default use_json_as_text argument
 
 select * from json_populate_recordset(null::jpop,'[{"a":"blurfl","x":43.2},{"b":3,"c":"2012-01-20 10:42:53"}]') q;
@@ -447,3 +450,6 @@ select * from json_to_record('{"a":1,"b":"foo","c":"bar"}',true)
 
 select * from json_to_recordset('[{"a":1,"b":"foo","d":false},{"a":2,"b":"bar","c":true}]',false)
     as x(a int, b text, c boolean);
+
+select * from json_to_recordset('[{"a":1,"b":{"d":"foo"},"c":true},{"a":2,"c":false,"b":{"d":"bar"}}]', true)
+    as x(a int, b json, c boolean);