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SQL/JSON: Improve some error messages

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This improves some error messages emitted by SQL/JSON query functions
by mentioning column name when available, such as when they are
invoked as part of evaluating JSON_TABLE() columns.  To do so, a new
field column_name is added to both JsonFuncExpr and JsonExpr that is
only populated when creating those nodes for transformed JSON_TABLE()
columns.

While at it, relevant error messages are reworded for clarity.

Reported-by: Jian He <jian.universality@gmail.com>
Suggested-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxG_e0QLCgaELrr2ZNz7AxPeGCNKAORe3fHtFCQLsH4J4Q@mail.gmail.com
This commit is contained in:
Amit Langote 2024-04-18 14:33:47 +09:00
parent 40126ac68f
commit b4fad46b6b
10 changed files with 100 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
src/backend/executor/execExprInterp.c
View File

@ -4312,7 +4312,8 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
case JSON_QUERY_OP:
*op->resvalue = JsonPathQuery(item, path, jsexpr->wrapper, &empty,
!throw_error ? &error : NULL,
jsestate->args);
jsestate->args,
jsexpr->column_name);
*op->resnull = (DatumGetPointer(*op->resvalue) == NULL);
@ -4337,7 +4338,8 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
{
JsonbValue *jbv = JsonPathValue(item, path, &empty,
!throw_error ? &error : NULL,
jsestate->args);
jsestate->args,
jsexpr->column_name);
if (jbv == NULL)
{
@ -4407,30 +4409,33 @@ ExecEvalJsonExprPath(ExprState *state, ExprEvalStep *op,
/* Handle ON EMPTY. */
if (empty)
{
if (jsexpr->on_empty)
{
if (jsexpr->on_empty->btype == JSON_BEHAVIOR_ERROR)
ereport(ERROR,
errcode(ERRCODE_NO_SQL_JSON_ITEM),
errmsg("no SQL/JSON item"));
else
jsestate->empty.value = BoolGetDatum(true);
Assert(jsestate->jump_empty >= 0);
return jsestate->jump_empty;
}
else if (jsexpr->on_error->btype == JSON_BEHAVIOR_ERROR)
ereport(ERROR,
errcode(ERRCODE_NO_SQL_JSON_ITEM),
errmsg("no SQL/JSON item"));
else
jsestate->error.value = BoolGetDatum(true);
*op->resvalue = (Datum) 0;
*op->resnull = true;
if (jsexpr->on_empty)
{
if (jsexpr->on_empty->btype != JSON_BEHAVIOR_ERROR)
{
jsestate->empty.value = BoolGetDatum(true);
Assert(jsestate->jump_empty >= 0);
return jsestate->jump_empty;
}
}
else if (jsexpr->on_error->btype != JSON_BEHAVIOR_ERROR)
{
jsestate->error.value = BoolGetDatum(true);
Assert(!throw_error && jsestate->jump_error >= 0);
return jsestate->jump_error;
}
Assert(!throw_error && jsestate->jump_error >= 0);
return jsestate->jump_error;
if (jsexpr->column_name)
ereport(ERROR,
errcode(ERRCODE_NO_SQL_JSON_ITEM),
errmsg("no SQL/JSON item found for specified path of column \"%s\"",
jsexpr->column_name));
else
ereport(ERROR,
errcode(ERRCODE_NO_SQL_JSON_ITEM),
errmsg("no SQL/JSON item found for specified path"));
}
/*

1
src/backend/parser/parse_expr.c
View File

@ -4311,6 +4311,7 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func)
jsexpr = makeNode(JsonExpr);
jsexpr->location = func->location;
jsexpr->op = func->op;
jsexpr->column_name = func->column_name;
/*
* jsonpath machinery can only handle jsonb documents, so coerce the input

10
src/backend/parser/parse_jsontable.c
View File

@ -402,12 +402,6 @@ transformJsonTableColumn(JsonTableColumn *jtc, Node *contextItemExpr,
Node *pathspec;
JsonFuncExpr *jfexpr = makeNode(JsonFuncExpr);
/*
* XXX consider inventing JSON_TABLE_VALUE_OP, etc. and pass the column
* name via JsonExpr so that JsonPathValue(), etc. can provide error
* message tailored to JSON_TABLE(), such as by mentioning the column
* names in the message.
*/
if (jtc->coltype == JTC_REGULAR)
jfexpr->op = JSON_VALUE_OP;
else if (jtc->coltype == JTC_EXISTS)
@ -415,6 +409,10 @@ transformJsonTableColumn(JsonTableColumn *jtc, Node *contextItemExpr,
else
jfexpr->op = JSON_QUERY_OP;
/* Pass the column name so any runtime JsonExpr errors can print it. */
Assert(jtc->name != NULL);
jfexpr->column_name = pstrdup(jtc->name);
jfexpr->context_item = makeJsonValueExpr((Expr *) contextItemExpr, NULL,
makeJsonFormat(JS_FORMAT_DEFAULT,
JS_ENC_DEFAULT,

45
src/backend/utils/adt/jsonpath_exec.c
View File

@ -3899,7 +3899,8 @@ JsonPathExists(Datum jb, JsonPath *jp, bool *error, List *vars)
*/
Datum
JsonPathQuery(Datum jb, JsonPath *jp, JsonWrapper wrapper, bool *empty,
bool *error, List *vars)
bool *error, List *vars,
const char *column_name)
{
JsonbValue *singleton;
bool wrap;
@ -3950,10 +3951,17 @@ JsonPathQuery(Datum jb, JsonPath *jp, JsonWrapper wrapper, bool *empty,
return (Datum) 0;
}
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression in JSON_QUERY should return singleton item without wrapper"),
errhint("Use WITH WRAPPER clause to wrap SQL/JSON item sequence into array.")));
if (column_name)
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression for column \"%s\" should return single item without wrapper",
column_name),
errhint("Use WITH WRAPPER clause to wrap SQL/JSON items into array.")));
else
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression in JSON_QUERY should return single item without wrapper"),
errhint("Use WITH WRAPPER clause to wrap SQL/JSON items into array.")));
}
if (singleton)
@ -3970,7 +3978,8 @@ JsonPathQuery(Datum jb, JsonPath *jp, JsonWrapper wrapper, bool *empty,
* *error to true. *empty is set to true if no match is found.
*/
JsonbValue *
JsonPathValue(Datum jb, JsonPath *jp, bool *empty, bool *error, List *vars)
JsonPathValue(Datum jb, JsonPath *jp, bool *empty, bool *error, List *vars,
const char *column_name)
{
JsonbValue *res;
JsonValueList found = {0};
@ -4006,9 +4015,15 @@ JsonPathValue(Datum jb, JsonPath *jp, bool *empty, bool *error, List *vars)
return NULL;
}
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression in JSON_VALUE should return singleton scalar item")));
if (column_name)
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression for column \"%s\" should return single scalar item",
column_name)));
else
ereport(ERROR,
(errcode(ERRCODE_MORE_THAN_ONE_SQL_JSON_ITEM),
errmsg("JSON path expression in JSON_VALUE should return single scalar item")));
}
res = JsonValueListHead(&found);
@ -4024,9 +4039,15 @@ JsonPathValue(Datum jb, JsonPath *jp, bool *empty, bool *error, List *vars)
return NULL;
}
ereport(ERROR,
(errcode(ERRCODE_SQL_JSON_SCALAR_REQUIRED),
errmsg("JSON path expression in JSON_VALUE should return singleton scalar item")));
if (column_name)
ereport(ERROR,
(errcode(ERRCODE_SQL_JSON_SCALAR_REQUIRED),
errmsg("JSON path expression for column \"%s\" should return single scalar item",
column_name)));
else
ereport(ERROR,
(errcode(ERRCODE_SQL_JSON_SCALAR_REQUIRED),
errmsg("JSON path expression in JSON_VALUE should return single scalar item")));
}
if (res->type == jbvNull)

2
src/include/nodes/parsenodes.h
View File

@ -1791,6 +1791,8 @@ typedef struct JsonFuncExpr
{
NodeTag type;
JsonExprOp op; /* expression type */
char *column_name; /* JSON_TABLE() column name or NULL if this is
* not for a JSON_TABLE() */
JsonValueExpr *context_item; /* context item expression */
Node *pathspec; /* JSON path specification expression */
List *passing; /* list of PASSING clause arguments, if any */

3
src/include/nodes/primnodes.h
View File

@ -1782,6 +1782,9 @@ typedef struct JsonExpr
JsonExprOp op;
char *column_name; /* JSON_TABLE() column name or NULL if this is
* not for a JSON_TABLE() */
/* jsonb-valued expression to query */
Node *formatted_expr;

6
src/include/utils/jsonpath.h
View File

@ -300,9 +300,11 @@ typedef struct JsonPathVariable
/* SQL/JSON item */
extern bool JsonPathExists(Datum jb, JsonPath *path, bool *error, List *vars);
extern Datum JsonPathQuery(Datum jb, JsonPath *jp, JsonWrapper wrapper,
bool *empty, bool *error, List *vars);
bool *empty, bool *error, List *vars,
const char *column_name);
extern JsonbValue *JsonPathValue(Datum jb, JsonPath *jp, bool *empty,
bool *error, List *vars);
bool *error, List *vars,
const char *column_name);
extern PGDLLIMPORT const TableFuncRoutine JsonbTableRoutine;

10
src/test/regress/expected/sqljson_jsontable.out
View File

@ -492,11 +492,11 @@ FROM
ON true;
ERROR: invalid input syntax for type integer: "err"
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int PATH '$.a' ERROR ON EMPTY)) jt;
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path of column "a"
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int PATH 'strict $.a' ERROR ON ERROR) ERROR ON ERROR) jt;
ERROR: jsonpath member accessor can only be applied to an object
SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int PATH 'lax $.a' ERROR ON EMPTY) ERROR ON ERROR) jt;
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path of column "a"
SELECT * FROM JSON_TABLE(jsonb '"a"', '$' COLUMNS (a int PATH '$' DEFAULT 1 ON EMPTY DEFAULT 2 ON ERROR)) jt;
a
---
@ -637,6 +637,10 @@ SELECT * FROM JSON_TABLE(jsonb '{"a": 123}', '$' || '.' || 'a' COLUMNS (foo int)
ERROR: only string constants are supported in JSON_TABLE path specification
LINE 1: SELECT * FROM JSON_TABLE(jsonb '{"a": 123}', '$' || '.' || '...
^
-- JsonPathQuery() error message mentioning column name
SELECT * FROM JSON_TABLE('{"a": [{"b": "1"}, {"b": "2"}]}', '$' COLUMNS (b json path '$.a[*].b' ERROR ON ERROR));
ERROR: JSON path expression for column "b" should return single item without wrapper
HINT: Use WITH WRAPPER clause to wrap SQL/JSON items into array.
-- JSON_TABLE: nested paths
-- Duplicate path names
SELECT * FROM JSON_TABLE(
@ -849,7 +853,7 @@ SELECT sub.* FROM s,
xx int path '$.c',
NESTED PATH '$.a.za[1]' columns (NESTED PATH '$.z21[*]' COLUMNS (z21 int path '$?(@ >= $"x")' ERROR ON ERROR))
)) sub;
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path of column "z21"
-- Parent columns xx1, xx appear before NESTED ones
SELECT sub.* FROM s,
(VALUES (23)) x(x), generate_series(13, 13) y,

30
src/test/regress/expected/sqljson_queryfuncs.out
View File

@ -339,7 +339,7 @@ SELECT JSON_VALUE(jsonb '[]', '$');
(1 row)
SELECT JSON_VALUE(jsonb '[]', '$' ERROR ON ERROR);
ERROR: JSON path expression in JSON_VALUE should return singleton scalar item
ERROR: JSON path expression in JSON_VALUE should return single scalar item
SELECT JSON_VALUE(jsonb '{}', '$');
json_value
------------
@ -347,7 +347,7 @@ SELECT JSON_VALUE(jsonb '{}', '$');
(1 row)
SELECT JSON_VALUE(jsonb '{}', '$' ERROR ON ERROR);
ERROR: JSON path expression in JSON_VALUE should return singleton scalar item
ERROR: JSON path expression in JSON_VALUE should return single scalar item
SELECT JSON_VALUE(jsonb '1', '$.a');
json_value
------------
@ -363,9 +363,9 @@ SELECT JSON_VALUE(jsonb '1', 'strict $.a' DEFAULT 'error' ON ERROR);
(1 row)
SELECT JSON_VALUE(jsonb '1', 'lax $.a' ERROR ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_VALUE(jsonb '1', 'lax $.a' ERROR ON EMPTY ERROR ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_VALUE(jsonb '1', 'strict $.a' DEFAULT 2 ON ERROR);
json_value
------------
@ -397,9 +397,9 @@ SELECT JSON_VALUE(jsonb '1', 'lax $.a' DEFAULT '2' ON EMPTY DEFAULT '3' ON ERROR
(1 row)
SELECT JSON_VALUE(jsonb '1', 'lax $.a' ERROR ON EMPTY DEFAULT '3' ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_VALUE(jsonb '[1,2]', '$[*]' ERROR ON ERROR);
ERROR: JSON path expression in JSON_VALUE should return singleton scalar item
ERROR: JSON path expression in JSON_VALUE should return single scalar item
SELECT JSON_VALUE(jsonb '[1,2]', '$[*]' DEFAULT '0' ON ERROR);
json_value
------------
@ -758,7 +758,7 @@ SELECT JSON_QUERY(jsonb '[]', '$[*]' EMPTY OBJECT ON EMPTY);
(1 row)
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON EMPTY);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[]', '$[*]' DEFAULT '"empty"' ON EMPTY);
json_query
------------
@ -766,18 +766,18 @@ SELECT JSON_QUERY(jsonb '[]', '$[*]' DEFAULT '"empty"' ON EMPTY);
(1 row)
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON EMPTY NULL ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON EMPTY EMPTY ARRAY ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON EMPTY EMPTY OBJECT ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON EMPTY ERROR ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[]', '$[*]' ERROR ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
SELECT JSON_QUERY(jsonb '[1,2]', '$[*]' ERROR ON ERROR);
ERROR: JSON path expression in JSON_QUERY should return singleton item without wrapper
HINT: Use WITH WRAPPER clause to wrap SQL/JSON item sequence into array.
ERROR: JSON path expression in JSON_QUERY should return single item without wrapper
HINT: Use WITH WRAPPER clause to wrap SQL/JSON items into array.
SELECT JSON_QUERY(jsonb '[1,2]', '$[*]' DEFAULT '"empty"' ON ERROR);
json_query
------------
@ -1033,7 +1033,7 @@ SELECT JSON_QUERY(jsonb '{"a": 1}', '$.b' RETURNING sqljsonb_int_not_null);
(1 row)
SELECT JSON_QUERY(jsonb '{"a": 1}', '$.b' RETURNING sqljsonb_int_not_null ERROR ON ERROR);
ERROR: no SQL/JSON item
ERROR: no SQL/JSON item found for specified path
-- Test timestamptz passing and output
SELECT JSON_QUERY(jsonb 'null', '$ts' PASSING timestamptz '2018-02-21 12:34:56 +10' AS ts);
json_query

3
src/test/regress/sql/sqljson_jsontable.sql
View File

@ -290,6 +290,9 @@ FROM JSON_TABLE(
-- Should fail (not supported)
SELECT * FROM JSON_TABLE(jsonb '{"a": 123}', '$' || '.' || 'a' COLUMNS (foo int));
-- JsonPathQuery() error message mentioning column name
SELECT * FROM JSON_TABLE('{"a": [{"b": "1"}, {"b": "2"}]}', '$' COLUMNS (b json path '$.a[*].b' ERROR ON ERROR));
-- JSON_TABLE: nested paths
-- Duplicate path names