amorfo77/json
1
0
Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-10-03 13:10:33 +00:00
Code Issues Packages Projects Releases Wiki Activity

create objects for tokens that cannot be array indices (#5357)

Browse Source 
When operator[](json_pointer) traverses a level that does not exist yet,
the null value is turned into an array or an object depending on the
reference token. The check only tested whether all characters are digits,
so tokens that can never be a valid array index selected an array and
then failed:

- "01" (and any other token with a leading '0') threw parse_error.106
- the empty token threw out_of_range.404

Both tokens are valid object keys, and both work when the level already
exists as an object, so creating the level changed the outcome. Test the
token against the RFC 6901, Sect. 4 grammar for array indices instead, so
that such tokens create an object. This only affects pointers that threw
before.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-08-04 08:51:54 +02:00
parent ad94fb01cc
commit db1d0983e6
4 changed files with 91 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/src/unit-json_pointer.cpp
+66
View File
@@ -396,6 +396,72 @@ TEST_CASE("JSON pointers")
}
}
SECTION("creating intermediate levels")
{
SECTION("tokens that are valid array indices create arrays")
{
json j;
j["/0"_json_pointer] = 1;
CHECK(j == json({1}));
json j2;
j2["/2"_json_pointer] = 1;
CHECK(j2 == json({nullptr, nullptr, 1}));
json j3;
j3["/-"_json_pointer] = 1;
CHECK(j3 == json({1}));
json j4;
j4["/foo/0/0"_json_pointer] = 1;
CHECK(j4 == json({{"foo", {{1}}}}));
}
SECTION("tokens that are no valid array indices create objects")
{
json j;
j["/one"_json_pointer] = 1;
CHECK(j == json({{"one", 1}}));
// leading '0' can never be a valid array index (RFC 6901, Sect. 4)
json j2;
j2["/01"_json_pointer] = 1;
CHECK(j2 == json({{"01", 1}}));
// the empty token is a valid object key, but no valid array index
json j3;
j3["/"_json_pointer] = 1;
CHECK(j3 == json({{"", 1}}));
}
SECTION("creating a level yields the same result as reusing it (#5357)")
{
json j;
j["/a/b/01/d"_json_pointer] = "value";
json j_init = json::object();
j_init["/a/b"_json_pointer] = json::object();
j_init["/a/b/01/d"_json_pointer] = "value";
const json expected = json::parse(R"({"a":{"b":{"01":{"d":"value"}}}})");
CHECK(j == expected);
CHECK(j_init == expected);
// unflatten uses the same key
const json flat = {{"/a/b/01/d", "value"}};
CHECK(flat.unflatten() == expected);
}
SECTION("existing arrays still reject invalid indices")
{
json j = {1, 2, 3};
CHECK_THROWS_WITH_AS(j["/01"_json_pointer],
"[json.exception.parse_error.106] parse error: array index '01' must not begin with '0'", json::parse_error&);
CHECK_THROWS_WITH_AS(j.at("/01"_json_pointer),
"[json.exception.parse_error.106] parse error: array index '01' must not begin with '0'", json::parse_error&);
}
}
SECTION("flatten")
{
json j =