MDEV-23187: Assorted assertion failures in json_find_path with certainbb-10.9-MDEV-2318710.9

collations

Analysis:
When we have negative index, the value in array_counter[] array is going to
be -1 at some point ( because in case of negative index in json path, the
initial value for a path with negative index is -<size_of_array>, and as we
move forward in array while parsing it and finding path, this value
increments). Since SKIPPED_STEP_MARK, is maximum uint value, it gets
compared to some int value in the array and eventually equates to -1
and messes with path.
Fix:
Make SKIPPED_STEP_MARK maximum of INT32.

3 files changed, 51 insertions, 1 deletions

diff --git a/mysql-test/main/func_json.result b/mysql-test/main/func_json.result
index 8cbc5305405..5af8e658d34 100644
--- a/mysql-test/main/func_json.result
+++ b/mysql-test/main/func_json.result
@@ -2578,5 +2578,29 @@ SELECT JSON_EXTRACT('{ "my-key": 1 }', '$.my-key');
 JSON_EXTRACT('{ "my-key": 1 }', '$.my-key')
 1
 #
+# MDEV-23187: Assorted assertion failures in json_find_path with certain collations
+#
+SET @save_collation_connection= @@collation_connection;
+SET @json='{ "A": [ [{"k":"v"},[1]],true],"B": {"C": 1} }';
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+JSON_VALUE(@json,'$.A[last-1][last-1].key1')
+NULL
+SET @json='{ "A": [ [{"k":"v"},[1]],true],"B": {"C": 1} }';
+SET collation_connection='ucs2_bin';
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+JSON_VALUE(@json,'$.A[last-1][last-1].key1')
+NULL
+SET @json='{ "A": [ [{"k":"v"},[15]],true],"B": {"C": 1} }';
+SET sql_mode=0,character_set_connection=utf32;
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+JSON_VALUE(@json,'$.A[last-1][last-1].key1')
+NULL
+SET @json='{ "A": [ [{"k":"v"},[15]],true],"B": {"C": 1} }';
+SET sql_mode=0,character_set_connection=utf32;
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+JSON_VALUE(@json,'$.A[last-1][last-1].key1')
+NULL
+SET @@collation_connection= @save_collation_connection;
+#
 # End of 10.9 Test
 #
diff --git a/mysql-test/main/func_json.test b/mysql-test/main/func_json.test
index 9bf0c9bae05..23a703ca716 100644
--- a/mysql-test/main/func_json.test
+++ b/mysql-test/main/func_json.test
@@ -1773,5 +1773,31 @@ SELECT JSON_EXTRACT('{ "my-key": 1 }', '$."my-key"');
 SELECT JSON_EXTRACT('{ "my-key": 1 }', '$.my-key');
 
 --echo #
+--echo # MDEV-23187: Assorted assertion failures in json_find_path with certain collations
+--echo #
+
+
+SET @save_collation_connection= @@collation_connection;
+
+SET @json='{ "A": [ [{"k":"v"},[1]],true],"B": {"C": 1} }';
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+
+SET @json='{ "A": [ [{"k":"v"},[1]],true],"B": {"C": 1} }';
+SET collation_connection='ucs2_bin';
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+
+SET @json='{ "A": [ [{"k":"v"},[15]],true],"B": {"C": 1} }';
+SET sql_mode=0,character_set_connection=utf32;
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+
+
+SET @json='{ "A": [ [{"k":"v"},[15]],true],"B": {"C": 1} }';
+SET sql_mode=0,character_set_connection=utf32;
+SELECT JSON_VALUE(@json,'$.A[last-1][last-1].key1');
+
+SET @@collation_connection= @save_collation_connection;
+
+
+--echo #
 --echo # End of 10.9 Test
 --echo #
diff --git a/strings/json_lib.c b/strings/json_lib.c
index 903dec978b4..920fb1d4a89 100644
--- a/strings/json_lib.c
+++ b/strings/json_lib.c
@@ -1324,7 +1324,7 @@ int json_skip_key(json_engine_t *j)
 }
 
 
-#define SKIPPED_STEP_MARK ((int) ~0)
+#define SKIPPED_STEP_MARK INT_MAX32
 
 /*
   Current step of the patch matches the JSON construction.