starred/json
1
0
Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-09-29 22:10:47 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

Name the key type when rejecting non-string CBOR/MessagePack map keys (#5594)

Browse Source 
* Name the key type when rejecting non-string CBOR/MessagePack map keys

CBOR and MessagePack allow map keys of any type, but JSON object keys
are always strings, so such maps are rejected. The error so far was the
one for a malformed string (e.g. "expected length specification
(0xA0-0xBF, 0xD9-0xDB); last byte: 0xC0" for a nil key), which does not
tell the user what went wrong. Report the type of the key instead:

  syntax error while parsing MessagePack object key: only string keys
  are supported, but found nil; last byte: 0xC0

The exception id (parse_error.113) and type are unchanged. Malformed
string keys and a missing key keep their previous messages. Document
the restriction on the CBOR and MessagePack pages.

Refs #2766, #3381

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Point the MessagePack key note to the spec's profile section

The note linked to "Serialization: type to format conversion", which says nothing about key types. Restricting map keys to strings is only mentioned in the "Profile" section (under "Future discussion") as an example of a JSON-compatible profile, so link there and describe it as such instead of as a permission.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-28 17:51:07 +02:00
committed by GitHub
parent 373005f7ac
commit 9e1a09eec0
10 changed files with 484 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/src/unit-cbor.cpp
+43 -2
View File
@@ -1830,10 +1830,51 @@ TEST_CASE("CBOR")
SECTION("invalid string in map")
{
json _;
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xa1, 0xff, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0xFF", json::parse_error&);
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xa1, 0xff, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR object key: only string keys are supported, but found a break stop code; last byte: 0xFF", json::parse_error&);
CHECK(json::from_cbor(std::vector<uint8_t>({0xa1, 0xff, 0x01}), true, false).is_discarded());
}
SECTION("non-string key (see #2766 and #3381)")
{
// only text strings map to JSON object keys; any other key is
// rejected with a message naming its type
const std::vector<std::pair<std::vector<std::uint8_t>, std::string>> cases =
{
{{0xA1, 0x01, 0x01}, "an unsigned integer; last byte: 0x01"},
{{0xA1, 0x20, 0x01}, "a negative integer; last byte: 0x20"},
{{0xA1, 0x41, 0x61, 0x01}, "a byte string; last byte: 0x41"},
{{0xA1, 0x80, 0x01}, "an array; last byte: 0x80"},
{{0xA1, 0xA0, 0x01}, "a map; last byte: 0xA0"},
{{0xA1, 0xC0, 0x61, 0x61, 0x01}, "a tag; last byte: 0xC0"},
{{0xA1, 0xF4, 0x01}, "a boolean; last byte: 0xF4"},
{{0xA1, 0xF5, 0x01}, "a boolean; last byte: 0xF5"},
{{0xA1, 0xF6, 0x01}, "null; last byte: 0xF6"},
{{0xA1, 0xF7, 0x01}, "undefined; last byte: 0xF7"},
{{0xA1, 0xF9, 0x3C, 0x00, 0x01}, "a floating-point number; last byte: 0xF9"},
{{0xA1, 0xFA, 0x3F, 0x80, 0x00, 0x00, 0x01}, "a floating-point number; last byte: 0xFA"},
{{0xA1, 0xFB, 0x3F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01}, "a floating-point number; last byte: 0xFB"},
{{0xA1, 0xE0, 0x01}, "a simple value; last byte: 0xE0"},
{{0xA1, 0xF8, 0x20, 0x01}, "a simple value; last byte: 0xF8"},
// indefinite-length map
{{0xBF, 0x01, 0x01, 0xFF}, "an unsigned integer; last byte: 0x01"},
};
for (const auto& c : cases)
{
CAPTURE(c.first)
const std::string expected = "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR object key: only string keys are supported, but found " + c.second;
json _;
CHECK_THROWS_WITH_AS(_ = json::from_cbor(c.first), expected.c_str(), json::parse_error&);
CHECK(json::from_cbor(c.first, true, false).is_discarded());
}
// a key of major type 3 with a reserved length is still reported as
// a malformed string, and a missing key as the end of input
json _;
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1})), "[json.exception.parse_error.110] parse error at byte 2: syntax error while parsing CBOR string: unexpected end of input", json::parse_error&);
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0x7C, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x7C", json::parse_error&);
}
SECTION("invalid UTF-8 in string (see #5529)")
{
// a two-character text string (major type 3) whose bytes are not
@@ -2284,7 +2325,7 @@ TEST_CASE("CBOR indefinite-length strings do not recurse per chunk")
SECTION("a break marker outside an indefinite-length string is not a string")
{
// 0xFF only closes a string that was opened; on its own it is not one
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0xFF, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0xFF", json::parse_error&);
CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0xFF, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR object key: only string keys are supported, but found a break stop code; last byte: 0xFF", json::parse_error&);
}
}