Fix(duckdb): fix JSON pointer path parsing, reduce warning noise (tobymao#2911)

* Fix(duckdb): fix JSON pointer path parsing, reduce warning noise

* Rename

Author: georgesittas

sqlglot/dialects/dialect.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import logging
 import typing as t
 from enum import Enum, auto
 from functools import reduce
@@ -8,7 +9,7 @@
 from sqlglot.errors import ParseError
 from sqlglot.generator import Generator
 from sqlglot.helper import AutoName, flatten, is_int, seq_get
-from sqlglot.jsonpath import generate as generate_json_path
+from sqlglot.jsonpath import generate as generate_json_path, parse as parse_json_path
 from sqlglot.parser import Parser
 from sqlglot.time import TIMEZONES, format_time
 from sqlglot.tokens import Token, Tokenizer, TokenType
@@ -20,6 +21,8 @@
 if t.TYPE_CHECKING:
     from sqlglot._typing import B, E
 
+logger = logging.getLogger("sqlglot")
+
 
 class Dialects(str, Enum):
     """Dialects supported by SQLGLot."""
@@ -441,6 +444,19 @@ def quote_identifier(self, expression: E, identify: bool = True) -> E:
 
         return expression
 
+    def to_json_path(self, path: t.Optional[exp.Expression]) -> t.Optional[exp.Expression]:
+        if isinstance(path, exp.Literal):
+            path_text = path.name
+            if path.is_number:
+                path_text = f"[{path_text}]"
+
+            try:
+                return exp.JSONPath(expressions=parse_json_path(path_text))
+            except ParseError:
+                logger.warning(f"Invalid JSON path syntax: {path_text}")
+
+        return path
+
     def parse(self, sql: str, **opts) -> t.List[t.Optional[exp.Expression]]:
         return self.parser(**opts).parse(self.tokenize(sql), sql)
 

sqlglot/dialects/duckdb.py

@@ -171,6 +171,18 @@ class DuckDB(Dialect):
     # https://duckdb.org/docs/sql/introduction.html#creating-a-new-table
     NORMALIZATION_STRATEGY = NormalizationStrategy.CASE_INSENSITIVE
 
+    def to_json_path(self, path: t.Optional[exp.Expression]) -> t.Optional[exp.Expression]:
+        if isinstance(path, exp.Literal):
+            # DuckDB also supports the JSON pointer syntax, where every path starts with a `/`.
+            # Additionally, it allows accessing the back of lists using the `[#-i]` syntax.
+            # This check ensures we'll avoid trying to parse these as JSON paths, which can
+            # either result in a noisy warning or in an invalid representation of the path.
+            path_text = path.name
+            if path_text.startswith("/") or "[#" in path_text:
+                return path
+
+        return super().to_json_path(path)
+
     class Tokenizer(tokens.Tokenizer):
         KEYWORDS = {
             **tokens.Tokenizer.KEYWORDS,

sqlglot/parser.py

@@ -7,7 +7,6 @@
 from sqlglot import exp
 from sqlglot.errors import ErrorLevel, ParseError, concat_messages, merge_errors
 from sqlglot.helper import apply_index_offset, ensure_list, seq_get
-from sqlglot.jsonpath import parse as _parse_json_path
 from sqlglot.time import format_time
 from sqlglot.tokens import Token, Tokenizer, TokenType
 from sqlglot.trie import TrieResult, in_trie, new_trie
@@ -61,22 +60,11 @@ def parse_logarithm(args: t.List, dialect: Dialect) -> exp.Func:
     return (exp.Ln if dialect.parser_class.LOG_DEFAULTS_TO_LN else exp.Log)(this=this)
 
 
-def parse_json_path(path: t.Optional[exp.Expression]) -> t.Optional[exp.Expression]:
-    if isinstance(path, exp.Literal):
-        path_text = path.name
-        if path.is_number:
-            path_text = f"[{path_text}]"
-        try:
-            return exp.JSONPath(expressions=_parse_json_path(path_text))
-        except ParseError:
-            logger.warning(f"Invalid JSON path syntax: {path_text}")
-
-    return path
-
-
-def parse_extract_json_with_path(expr_type: t.Type[E]) -> t.Callable[[t.List], E]:
-    def _parser(args: t.List) -> E:
-        expression = expr_type(this=seq_get(args, 0), expression=parse_json_path(seq_get(args, 1)))
+def parse_extract_json_with_path(expr_type: t.Type[E]) -> t.Callable[[t.List, Dialect], E]:
+    def _parser(args: t.List, dialect: Dialect) -> E:
+        expression = expr_type(
+            this=seq_get(args, 0), expression=dialect.to_json_path(seq_get(args, 1))
+        )
         if len(args) > 2 and expr_type is exp.JSONExtract:
             expression.set("expressions", args[2:])
 
@@ -558,12 +546,12 @@ class Parser(metaclass=_Parser):
         TokenType.ARROW: lambda self, this, path: self.expression(
             exp.JSONExtract,
             this=this,
-            expression=parse_json_path(path),
+            expression=self.dialect.to_json_path(path),
         ),
         TokenType.DARROW: lambda self, this, path: self.expression(
             exp.JSONExtractScalar,
             this=this,
-            expression=parse_json_path(path),
+            expression=self.dialect.to_json_path(path),
         ),
         TokenType.HASH_ARROW: lambda self, this, path: self.expression(
             exp.JSONBExtract,

tests/dialects/test_duckdb.py

@@ -89,6 +89,14 @@ def test_duckdb(self):
                 },
             )
 
+        self.validate_identity("""SELECT '{"duck": [1, 2, 3]}' -> '$.duck[#-1]'""")
+        self.validate_all(
+            """SELECT JSON_EXTRACT('{"duck": [1, 2, 3]}', '/duck/0')""",
+            write={
+                "": """SELECT JSON_EXTRACT('{"duck": [1, 2, 3]}', '/duck/0')""",
+                "duckdb": """SELECT '{"duck": [1, 2, 3]}' -> '/duck/0'""",
+            },
+        )
         self.validate_all(
             """SELECT JSON('{"fruit":"banana"}') -> 'fruit'""",
             write={