Fix CBOR tag handlers not recognizing tags 0-5 and 21-23 (#5331)

* Fix CBOR tag handlers not recognizing tags 0-5 and 21-23

The tagged-item switch in binary_reader::parse_cbor_internal() only handled
head bytes 0xC6-0xD4 and 0xD8-0xDB. Bytes 0xC0-0xC5 (tags 0-5: date/time,
epoch, bignum, decimal, bigfloat) and 0xD5-0xD7 (tags 21-23: base64url,
base64, base16 conversion hints) fell through to the default case and were
reported as invalid bytes, even under cbor_tag_handler_t::ignore and ::store,
despite being valid CBOR major-type-6 tags per RFC 8949.

Add the missing case labels so the full 0xC0-0xDB range is handled
uniformly. Extend the "Tagged values" test in unit-cbor.cpp to cover
0xC0-0xD7, and update the CBOR docs to state the corrected tag range.

Fixes #5315

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>

* Fix stale CBOR tag docs and add store-mode binary-payload test

The "Incomplete mapping" warning still listed tags 0-5 (date/time,
bignum, decimal fraction, bigfloat) and 21-23 (expected conversions)
as unsupported, even though they now parse correctly under
cbor_tag_handler_t::ignore/store, same as 0xC6..0xD4/0xD8..0xDB.
Remove those five bullets and cross-reference the "Tagged items"
warning below, matching the equivalent docs fix landed independently
in PR #5367.

Also add a cbor_tag_handler_t::store test that wraps a binary
payload (not just a string) for every byte in 0xC0..0xD7, confirming
these tags are unwrapped the same way as 0xC6..0xD4 rather than
mistaken for the 0xD8..0xDB binary-subtype marker syntax, per review
feedback on #5331.

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>

---------

Signed-off-by: sahilkamate03 <45514385+sahilkamate03@users.noreply.github.com>
This commit is contained in:
Sahil_Kamate
2026-08-19 20:19:47 +02:00
committed by GitHub
parent ce87157d4e
commit b5378e8deb
4 changed files with 36 additions and 10 deletions
+13 -2
View File
@@ -2565,11 +2565,16 @@ TEST_CASE("Tagged values")
const json j = "s";
auto v = json::to_cbor(j);
SECTION("0xC6..0xD4")
const json j_bin_payload = json::binary(std::vector<std::uint8_t> {0x01, 0x02, 0x03});
auto v_bin_payload = json::to_cbor(j_bin_payload);
SECTION("0xC0..0xD7")
{
for (const auto b : std::vector<std::uint8_t>
{
0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4
0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5,
0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
0xD5, 0xD6, 0xD7
})
{
CAPTURE(b);
@@ -2589,6 +2594,12 @@ TEST_CASE("Tagged values")
auto j_tagged_stored = json::from_cbor(v_tagged, true, true, json::cbor_tag_handler_t::store);
CHECK(j_tagged_stored == j);
auto v_binary_tagged = v_bin_payload;
v_binary_tagged.insert(v_binary_tagged.begin(), b);
auto j_binary_tagged_stored = json::from_cbor(v_binary_tagged, true, true, json::cbor_tag_handler_t::store);
CHECK(j_binary_tagged_stored == j_bin_payload);
CHECK(!j_binary_tagged_stored.get_binary().has_subtype());
}
}