Remove dependence on -fwrapv semantics in jsonb.

This commit updates a couple of places in the jsonb code to no
longer rely on signed integer wrapping for correctness.  Like
commit 9e9a2b7031, this is intended to move us closer towards
removing -fwrapv, which may enable some compiler optimizations.
However, there is presently no plan to actually remove that
compiler option in the near future.

This commit makes use of the newly introduced pg_abs_s32() routine
to negate a signed integer (that is known to be negative) for
comparison with an unsigned integer.  In passing, change one use of
INT_MIN to the more portable PG_INT32_MIN.

Reported-by: Alexander Lakhin
Author: Joseph Koshakow
Reviewed-by: Jian He
Discussion: https://postgr.es/m/CAAvxfHdBPOyEGS7s%2Bxf4iaW0-cgiq25jpYdWBqQqvLtLe_t6tw%40mail.gmail.com

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 5ecb9fffae221333cb06f56b1cec47a6376c6938..1f8ea51e6adfb5b731595f1c86d6c448d171139c 100644 (file)
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -18,6 +18,7 @@
 
 #include "access/htup_details.h"
 #include "catalog/pg_type.h"
+#include "common/int.h"
 #include "common/jsonapi.h"
 #include "common/string.h"
 #include "fmgr.h"
@@ -946,7 +947,7 @@ jsonb_array_element(PG_FUNCTION_ARGS)
    {
        uint32      nelements = JB_ROOT_COUNT(jb);
 
-       if (-element > nelements)
+       if (pg_abs_s32(element) > nelements)
            PG_RETURN_NULL();
        else
            element += nelements;
@@ -5426,7 +5427,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 
    if (idx < 0)
    {
-       if (-idx > nelems)
+       if (pg_abs_s32(idx) > nelems)
        {
            /*
             * If asked to keep elements position consistent, it's not allowed
@@ -5438,7 +5439,7 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
                         errmsg("path element at position %d is out of range: %d",
                                level + 1, idx)));
            else
-               idx = INT_MIN;
+               idx = PG_INT32_MIN;
        }
        else
            idx = nelems + idx;

diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out
index e66d7601899c87f9d03ee2a949041770bf46dac1..7d163a156e3f413f126898c8e024ae2b865601fa 100644 (file)
--- a/src/test/regress/expected/jsonb.out
+++ b/src/test/regress/expected/jsonb.out
@@ -680,6 +680,12 @@ select '"foo"'::jsonb -> 'z';
  
 (1 row)
 
+select '[]'::jsonb -> -2147483648;
+ ?column? 
+----------
+ 
+(1 row)
+
 select '{"a": [{"b": "c"}, {"b": "cc"}]}'::jsonb ->> null::text;
  ?column? 
 ----------
@@ -746,6 +752,12 @@ select '"foo"'::jsonb ->> 'z';
  
 (1 row)
 
+select '[]'::jsonb ->> -2147483648;
+ ?column? 
+----------
+ 
+(1 row)
+
 -- equality and inequality
 SELECT '{"x":"y"}'::jsonb = '{"x":"y"}'::jsonb;
  ?column? 
@@ -4575,6 +4587,12 @@ select jsonb_delete_path('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,
  {"a": 1, "b": [1, 2], "c": {"1": 2}, "d": {"1": [3]}, "n": null}
 (1 row)
 
+select jsonb_delete_path('{"a":[]}', '{"a",-2147483648}');
+ jsonb_delete_path 
+-------------------
+ {"a": []}
+(1 row)
+
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{n}';
                          ?column?                         
 ----------------------------------------------------------

diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql
index 97bc2242a13339e2c42d8955b0d66c53bf88f7b0..5f0190d5a2b7957f107d4d6cb24125caa2f0d883 100644 (file)
--- a/src/test/regress/sql/jsonb.sql
+++ b/src/test/regress/sql/jsonb.sql
@@ -204,6 +204,7 @@ select '[{"b": "c"}, {"b": "cc"}]'::jsonb -> 'z';
 select '{"a": "c", "b": null}'::jsonb -> 'b';
 select '"foo"'::jsonb -> 1;
 select '"foo"'::jsonb -> 'z';
+select '[]'::jsonb -> -2147483648;
 
 select '{"a": [{"b": "c"}, {"b": "cc"}]}'::jsonb ->> null::text;
 select '{"a": [{"b": "c"}, {"b": "cc"}]}'::jsonb ->> null::int;
@@ -216,6 +217,7 @@ select '[{"b": "c"}, {"b": "cc"}]'::jsonb ->> 'z';
 select '{"a": "c", "b": null}'::jsonb ->> 'b';
 select '"foo"'::jsonb ->> 1;
 select '"foo"'::jsonb ->> 'z';
+select '[]'::jsonb ->> -2147483648;
 
 -- equality and inequality
 SELECT '{"x":"y"}'::jsonb = '{"x":"y"}'::jsonb;
@@ -1185,6 +1187,7 @@ select jsonb_set('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::j
 select jsonb_delete_path('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}', '{n}');
 select jsonb_delete_path('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}', '{b,-1}');
 select jsonb_delete_path('{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}', '{d,1,0}');
+select jsonb_delete_path('{"a":[]}', '{"a",-2147483648}');
 
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{n}';
 select '{"n":null, "a":1, "b":[1,2], "c":{"1":2}, "d":{"1":[2,3]}}'::jsonb #- '{b,-1}';