tree 8a9730d886b52d082ebd0c66b57c5b19f84bc499
parent cf57414d83314bf05cb28ae8a600163b96855ba0
author Leonid Startsev <sandwwraith@users.noreply.github.com> 1697732203 +0200
committer GitHub <noreply@github.com> 1697732203 +0200
gpgsig -----BEGIN PGP SIGNATURE-----
 
 wsBcBAABCAAQBQJlMVZrCRBK7hj4Ov3rIwAAlMIIAAi22nubpANyzpE8XA1zhOqO
 MQ+9w80VE9vgrvLZ6VKwDO8AfYq0Hv8hNRFfWMpapR2VdtK2O9HPu3Y8bYRD8/A/
 RsM4OQdL8PA5thS7030JSaIj2ug5mnJjo6UPAt3Vkjcr8WWasitN3shvlYv52b1N
 lDoq5Pktk2uYG/vx9ZgYxshKuGYNxQ3boTPGjDVO2apBQT6McOviUe6/Zmx+jDUm
 Uj7fea4X7U1LMkewFf57bOlBCZzRLU99KyHFOh+WMZYnTeEwwKSRCKvNiTz4N/wx
 ahcY6Z0oihQ6dPht5LlN8kVj39x0yiqjulmYedYw7pf92o1JYz/rbV1/K7OeWCU=
 =1WI7
 -----END PGP SIGNATURE-----
 

Improve polymorphic deserialization optimization: (#2481)

Previously, when discriminator was found as the first key in Json, but there was no deserializer for it, we still fell back to a slow path with JsonTree.
It was actually meaningless because a slow path always throws exception when a serializer is not found.
Such behavior led to unnecessary memory pressure & consumption in exceptional cases (see linked ticket for details).

Also make polymorphic deserialization exception messages more meaningful and make them more consistent with serialization ones.

Also fix behavior when the actual discriminator value is JsonNull (it should be treated as missing, not as "null" string).

Fixes #2478